Community RSS Feed
https://community.wolfram.com
RSS Feed for Wolfram Community showing any discussions from all groups sorted by activeComparing string lists with partial match
https://community.wolfram.com/groups/-/m/t/2368753
I have two lists of file names, about 200-300 per list. (attached as text files below). The Intersection of the lists is smaller than expected, only around 50 or so; probably the result of appended version number updates.
What I seek is a list of file names that are nearly identical, but have version number updates. I can describe this more accurately as file names that match up to the first non-alphabetical character in the filename. In this case the set of 'alphabetical' characters I wish to allow for initial part of string match includes both dash and underscore.
How to approach parsing the names to address that notion?
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/1bdabc2e-63ed-4a0a-b549-a7ef758d4751Jonathan Wooldridge2021-09-18T01:37:53ZConvert equation to matrix form?
https://community.wolfram.com/groups/-/m/t/2362897
I want to convert set of equation into required matrix for my vibrational analysis. I am attaching herewith the two files. One with set of equation (named as questio1) and other one with required format(Named as required format).
Kindly help me out to get the final output.
input file/code
(A11 Amn \[Alpha]^2 + C11 Dmn \[Alpha]^2 - B11 Cmn \[Alpha]^3 +
A12 Bmn \[Alpha] \[Beta] + A66 Bmn \[Alpha] \[Beta] +
C12 Emn \[Alpha] \[Beta] + C66 Emn \[Alpha] \[Beta] +
A66 Amn \[Beta]^2 + C66 Dmn \[Beta]^2 -
B12 Cmn \[Alpha] \[Beta]^2 - 2 B66 Cmn \[Alpha] \[Beta]^2 -
Amn I0 \[Omega]^2 - Dmn I3 \[Omega]^2 +
Cmn I1 \[Alpha] \[Omega]^2) Cos[x \[Alpha]] Sin[y \[Beta]] == 0
(A12 Amn \[Alpha] \[Beta] + C12 Dmn \[Alpha] \[Beta] -
B12 Cmn \[Alpha]^2 \[Beta] - 2 B66 Cmn \[Alpha]^2 \[Beta] +
A22 Bmn \[Beta]^2 + C22 Emn \[Beta]^2 - B22 Cmn \[Beta]^3 +
A66 \[Alpha] (Bmn \[Alpha] + Amn \[Beta]) +
C66 \[Alpha] (Emn \[Alpha] + Dmn \[Beta]) - Bmn I0 \[Omega]^2 -
Emn I3 \[Omega]^2 + Cmn I1 \[Beta] \[Omega]^2) Cos[y \[Beta]] Sin[
x \[Alpha]] == 0
Required output
( {
{A11 \[Alpha] ^2 + A66 \[Beta]^2,
A12 \[Alpha] \[Beta] + A66 \[Alpha] \[Beta], -B11 \[Alpha]^3 -
B12 \[Alpha] \[Beta]^2 - 2 B66 \[Alpha] \[Beta]^2,
C11 \[Alpha]^2 + C66 \[Beta]^2,
C12 \[Alpha] \[Beta] + C66 \[Alpha] \[Beta]},
{A12 \[Alpha] \[Beta] + A66 \[Alpha] \[Beta],
A22 \[Beta]^2 + A66 \[Alpha]^2, -B12 \[Alpha]^2 \[Beta] -
B22 \[Beta]^3 - 2 B66 \[Alpha]^2 \[Beta],
C12 \[Alpha] \[Beta] + C66 \[Alpha] \[Beta],
C22 \[Beta]^2 + C66 \[Alpha]^2}
} ) - \[Omega]^2 ( {
{-I0, 0, \[Alpha] I1, -I4, 0},
{0, -I0, I1 \[Beta], 0, -I3}
} ) ( {
{Amn},
{Bmn},
{Cmn},
{Dmn},
{Emn}
} ) == 0vin Bha2021-09-09T10:14:52Z[WSG21] Daily study group on creating custom user interfaces
https://community.wolfram.com/groups/-/m/t/2355272
On September 7th we will begin our next Daily Study Group series that will focus on "**Creating Custom User Interfaces**". Attendees will learn to develop graphical user interfaces using the Wolfram Language through short live lessons hosted by Wolfram-certified instructors, and also work on practice problems and mini projects for a hands-on experience.
A certificate of program completion will be available.
Register [here][1].
[1]: https://www.bigmarker.com/series/daily-study-group-creating-custom-user-interfaces/series_details?utm_bmcr_source=communityAbrita Chakravarty2021-08-30T19:33:28ZCreate the large size of SparseArray
https://community.wolfram.com/groups/-/m/t/2368242
Hi Communities
I am trying to create a large size of sparsearray as following
base = Permutations[{1, 1, 1, 1, 1, 0, 0, 0, 0, 0}];
dim = Length[base]
AbsoluteTiming[
test = SparseArray[{i_,
j_} /; (Total@Abs[base[[i]] - base[[j]]] == 0 ||
Total@Abs[base[[i]] - base[[j]]] == 2 ||
Total@Abs[base[[i]] - base[[j]]] == 4) -> 1, dim {1, 1}]]
The ideal of above code is that only the element at diagonal of the matrix and only two and four element differ between two bases have the value of 1.
The above code took only ~0.6 second to complete.
However, if I change the `base` to following:
base = Select[
Permutations[{1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 0}],
5 <= Total@#[[1 ;; 10]] <= 7 && 5 <= Total@#[[11 ;; 15]] <= 5 &]
It ran out all of my computer's memory (~6GB) and makes the such computation being impossible.
The length of this new base is only 34122. It is not very large. So did I make any thing wrong?
Are there any solutions to this ?
Thank you for reading this.ddtty kuso2021-09-17T03:42:28ZHow to scale a binomial distribution by X with error?
https://community.wolfram.com/groups/-/m/t/2368432
I'm trying to simulate a binomial distribution [ n=8, p=0.22].
I want to scale the result by a known weight [e.g., 0.51].
This weight, however, has uncertainty [variance = 0.31] that should be factored in.
Is it possible in Mathematica to randomly scale an outcome by x plus or minus a given variance?
Thanks :)Matthew MacDougall2021-09-17T13:40:54ZHow to create a list from 100 to 0 decrementing?
https://community.wolfram.com/groups/-/m/t/2368904
Hi there !! I should feel embarrassed to ask such a simple question but I can not find any answers on the web....maybe because it is too simple... I use Nestlist[ floor[]] as in the lines below, but if I increase the number it won't give an answer, is there a simpler way to list from 100 to 0 {100,99,98,97,96...,3,2,1,0}? or from n->0?
n=1223
a=NestList[Floor[n--]&,n,n]Luis Felipe Massena Misiec2021-09-17T16:17:27ZLooking for experiences with linking graph drawing tools to Mathematica
https://community.wolfram.com/groups/-/m/t/253194
Mathematica doesn't have a drag, drop and link GUI. Now that the SystemModeler technology is there, it would be great to have its GUI integrated within Mathematica, so that we could create more sophisticated applications (I don't mean having the SystemModeler integrated; I just mean its GUI drag and drop kind of capabilities).
While waiting for it, has anyone ever tried to "link" Mathematica to softwares like dia, libreOffice Draw, yEd, Visio, etc?
Mathematica has different Graph import functionalities. But from the simple import, up to the processing of the schematics, in any way, and based on the user custom properties entered into each Graph object, and passing the processed info back to the graph, etc., there's probably a long distance to go (not to mention the workflow details of such an interaction: can we "double click" the object to call Mathematica on it, which is is best solution to customize to a less generic interface, etc).
Is there someone with an experience to share?Pedro Fonseca2014-05-17T10:25:16ZImport lines and nodal coordinates from a microstation .dgn file?
https://community.wolfram.com/groups/-/m/t/2368952
Hello, I was wondering if anyone has experience importing a microstation file (or scraping the data from the microstation file) into Mathematica. I do a lot of finite element math in Mathematica, and more specifically, a lot of bridge truss analysis. The process involves gathering nodal coordinates (Node Number, x coord, y coord, z coord) and element connectivity (node 1 and node 2 connect, node 2 and node 3 connect, etc.). As of now, I type in nodal coords and element connectivity manually into Mathematica and it takes some time. I was hoping there was a way to streamline the process and have Mathematica scrape the needed data from a 3D or 2D microstation "stick model" file. That way, all I need to do is draw the truss in microstation and my Mathematica script will read and solve the rest. Thanks in advance!Mark Converse2021-09-17T20:31:45ZProblem with plotting Sign[ ]: unexpected output
https://community.wolfram.com/groups/-/m/t/2367885
Hello,
1) I want to plot the sign of the square root of some function. One expects to obtain values {1} and {0} in the domain where the expression under the square root is positive or zero respectively. In addition to that, I have several pieces on the plot with values continuously ranging from -1 to 1. What is it and how can one avoid that?
The second question is similar.
2) I want to plot the sign of a quite complicated function. But in addition to domains with values {-1,0,1} I have a contribution with value continuously ranging from -1 to 1. What is it and how can one avoid that?
The notebook is enclosed.
[1]: https://www.wolframcloud.com/obj/e8383d34-d7a5-4383-a82f-b831b60a6a18Ilya Shabat2021-09-16T15:14:37ZModeling a cart-pole system in Wolfram SystemModeler
https://community.wolfram.com/groups/-/m/t/2368402
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/cc535bd8-c504-4d33-8147-41e164c8c6aeAlec Graves2021-09-17T02:02:25ZMathematica for iPad
https://community.wolfram.com/groups/-/m/t/372416
It would be great if there was an actual Mathematica client for iPad, or if the iPad isn't powerful enough, maybe a Wolfram Cloud access interface app.Joe Krishnapillai2014-10-18T21:45:07ZKernel slow start
https://community.wolfram.com/groups/-/m/t/2368712
Hi,
I just purchased Mathematica 12.3.1 Home Edition. I'm running it on a Microsoft Surface Book with Windows 10.
When I start Mathematica and enter a simple calculation, e.g., 2+2, it takes between 3-5 minutes for the kernel to initiate. After the kernel is initiated subsequent calculations are extremely fast.
Why is the kernel initiation so slow and what can I do to speed this up? Is there a logfile that I can read to understand? This is a very annoying issue.
Thanks,
ScottScott Beckman2021-09-17T13:27:29ZHow to Export image at 2x resolution?
https://community.wolfram.com/groups/-/m/t/2367030
Can someone suggest how to export a GIF at 2x resolution?
`Export` quality is perfect, but doesn't allow specifying `RasterSize`. Meanwhile using `Rasterize` reduces antialiasing quality. I suspect it's an issue of figuring what the default gif export function does and reproducing it
```System`Convert`CommonGraphicsDump`ExportElementsToRasterFormat["GIF", ##1]```
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/yaroslavvb/newton/forum-rasterize-bug.nbYaroslav Bulatov2021-09-15T09:12:55ZDefining range of variables for the whole notebook
https://community.wolfram.com/groups/-/m/t/2367980
Hi all,
At the start of a notebook, is there a way to define that a parameter belongs to a specific range such as [0,1]? I need Mathematica to know about the sign of the values under radicals and simplify them without being forced to repeat the Assuming function for the whole notebook over and over.Arash Roghani2021-09-17T06:10:16ZUnexpected results from FinancialData[ ]?
https://community.wolfram.com/groups/-/m/t/2368080
Clearly I must have made a mistake, the S&P500 did not gain 150% in 2016. So what did I do wrong, or is the data in FinancialData in error???
From the internet -- gains of the S&P500 by year
![enter image description here][1]
Table constructed from Mathematica
![enter image description here][2]
My code
rus3RtnYr = FinancialData["IWV", "Return", {{2010}, {2021}, "Year"}];
rus2RtnYr = FinancialData["IWN", "Return", {{2010}, {2021}, "Year"}];
spxRtnYr = FinancialData["SPX", "Return", {{2010}, {2021}, "Year"}];
djRtnYr = FinancialData["^DJI", "Return", {{2010}, {2021}, "Year"}];
Grid[Prepend[
Transpose[{Map[
DateString[DateList[#], {"MonthName", " ", "Year"}] &,
Flatten[rus3RtnYr[[2, 2]]]],
Map[PaddedForm[#, {2, 1}] &, Flatten[rus3RtnYr[[2, 1]]]],
Map[PaddedForm[#, {2, 1}] &, Flatten[rus2RtnYr[[2, 1]]]],
Map[PaddedForm[#, {2, 1}] &, Flatten[spxRtnYr[[2, 1]]]],
Map[PaddedForm[#, {2, 1}] &, Flatten[djRtnYr[[2, 1]]]]}], {"Date",
"Russell 3000", "Russell 2000", "S&P500", "DJIA"}],
Background -> {None, {LightRed[.3], {White,
Lighter[Blend[{Blue, Green}], .8]}}},
Dividers -> {{Darker[Gray, .6], {Lighter[Gray, .5]},
Darker[Gray, .6]}, {Darker[Gray, .6], Darker[Gray, .6], {False},
Darker[Gray, .6]}}, Alignment -> {{Center, Center, Center}},
ItemSize -> {{9, 8, 8, 8, 8}}, Frame -> Darker[Gray, .6],
ItemStyle -> 14, Spacings -> {.3, .8}]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=sp500table.PNG&userId=159426
[2]: https://community.wolfram.com//c/portal/getImageAttachment?filename=sp500mathe.PNG&userId=159426Raymond Low2021-09-16T22:22:39Z[UPDATES] Resources For Novel Coronavirus COVID-19
https://community.wolfram.com/groups/-/m/t/1872608
*Short URL to share this post*: https://wolfr.am/coronavirus
***JOIN*** *our* ***Medical Sciences*** *group for the latest updates & best networking*: https://wolfr.am/MedicalSciences
----------
This post is intended to be the hub for Wolfram resources related to novel coronavirus disease COVID-19 that originated in Wuhan, China. The larger aim is to provide a forum for disseminating ways in which Wolfram technologies and coding can be utilized to shed light on the virus and pandemic. Possibilities include using the Wolfram Language for data-mining, modeling, analysis, visualizations, and so forth. Among other things, we encourage comments and feedback on these resources. Please note that this is intended for technical analysis and discussion supported by computation. Aspects outside this scope and better suited for different forums should be avoided. Thank you for your contribution!
[![enter image description here][1]](https://www.wolframcloud.com/obj/examples/COVID19China)
[![enter image description here][2]](https://www.wolframcloud.com/obj/examples/COVID19US)
[![enter image description here][3]](https://www.wolframcloud.com/obj/examples/COVID19World)
[![enter image description here][4]](https://www.wolframcloud.com/obj/examples/COVID19Gene)
[![enter image description here][5]](https://www.wolframcloud.com/obj/examples/COVID19Patient)
[![enter image description here][6]](https://www.wolframcloud.com/obj/examples/COVID19Resources)
[![enter image description here][7]](https://www.wolframcloud.com/obj/examples/COVID19Dashboard)
*Short URL to share dashboard:* https://wolfr.am/COVID19Dashboard
## ________________________________________
## FEATURED CONTENT
- [COVID-19 Livestream Notebook March 24][8] by Stephen Wolfram
- [Agent-Based Networks Models for COVID-19][9] by Christopher Wolfram
- [Live-Stream: Exploring Pandemic Data][10] by Stephen & Christopher Wolfram + guests
- [Live-Stream: Exploring and Explaining Epidemic Modeling][11] by Stephen & Christopher Wolfram + guests
## ________________________________________
## [CALL for Making COVID-19 Data Computable (*link*)][12]
More pandemic-related information and data sets emerging every day. We invite people in the community to contribute to making more data surrounding this topic computable. Here is a call to action with some recommendations for people who want to do more, whether it's just pointing out relevant data sources, or taking the time to make some of that data computable and more instantly ready for other people to explore: https://wolfr.am/COVID-19-DATA .
## ________________________________________
## [Curated Computable Data (*link*)][13]
[FOLLOW THIS LINK][14] to see all available COVID-19 data repositories ready for computation in the Wolfram Language .
[Changes in Updates to SARS-CoV-2 Sequences in the Wolfram Data Repository][16]
We have published and are continuously updating the Wolfram Data Repository entries. Below are a few key ones. Follow the link above to browse all repositories. We encourage you to make [*your own contributions*][15] of curated data relevant to COVID-19.
> **Pandemic Data for Novel Coronavirus COVID-19**
> https://www.wolframcloud.com/obj/resourcesystem/published/DataRepository/resources/Epidemic-Data-for-Novel-Coronavirus-COVID-19
> **Genetic Sequences for the SARS-CoV-2 Coronavirus**
> https://datarepository.wolframcloud.com/resources/Genetic-Sequences-for-the-SARS-CoV-2-Coronavirus
> **Patient Medical Data for Novel Coronavirus COVID-19**
> https://datarepository.wolframcloud.com/resources/Patient-Medical-Data-for-Novel-Coronavirus-COVID-19
> **COVID-19 Hospital Resource Use Projections**
> https://datarepository.wolframcloud.com/resources/COVID-19-Hospital-Resource-Use-Projections
> **OECD Data: Hospital Beds Per Country**
> https://datarepository.wolframcloud.com/resources/OECD-Data-Hospital-Beds-Per-Country
> **Hospital Beds Per US State**
> https://datarepository.wolframcloud.com/resources/Hospital-Beds-Per-US-State
## ________________________________________
## [Computational Publications (*link*)][17]
We encourage you to share your computational explorations relevant to coronavirus on Wolfram Community as stand-alone articles and then comment with their URL links on this discussion thread. We will summarize these articles in the following list:
### ________________________________
###FEATURED
> **COVID-19 Livestream Notebook March 24** by Stephen Wolfram
> https://www.wolframcloud.com/obj/s.wolfram/Published/COVID-19-Livestream-March-24.nb
> **Agent-Based Networks Models for COVID-19** by Christopher Wolfram
> https://community.wolfram.com/groups/-/m/t/1907703
> **Epidemiological Models for Influenza and COVID-19** by Robert Nachbar
> https://community.wolfram.com/groups/-/m/t/1896178
> **Epidemic simulation with a polygon container** by Francisco Rodríguez
> https://community.wolfram.com/groups/-/m/t/1901002
> **Distance to nearest confirmed US COVID-19 case** by Chip Hurst
> https://community.wolfram.com/groups/-/m/t/1911583
### ________________________________
### EPIDEMIC MODELING: SIMULATION
> **Epidemic simulation with a polygon container** by Francisco Rodríguez
> https://community.wolfram.com/groups/-/m/t/1901002
> **Agent based epidemic simulation** by Jon McLoone
> https://community.wolfram.com/groups/-/m/t/1900481
> **Modeling the spatial spread of infection diseases in the US** by Diego Zviovich
> https://community.wolfram.com/groups/-/m/t/1889072
> **Geo-spatial-temporal COVID-19 simulations and visualizations over USA** by Diego Zviovich
> https://community.wolfram.com/groups/-/m/t/1900514
> **Life, Liberty, and Lockdowns: cellular automaton approach** by Philip Maymin
> https://community.wolfram.com/groups/-/m/t/2181433
### ________________________________
### EPIDEMIC MODELING: COMPARTMENTAL
> **Stochastic Epidemiology Models with Applications to the COVID-19** by Robert Nachbar
> https://community.wolfram.com/groups/-/m/t/1980051
> **COVID19: Italian SIRD estimates and prediction** by Christos Papahristodoulou
> https://community.wolfram.com/groups/-/m/t/1984320
> **Solver for COVID-19 epidemic model with the Caputo fractional derivatives** by Alexander Trounev
> https://community.wolfram.com/groups/-/m/t/1976589
> **Epidemiological Model for repetitive rapid testing for COVID-19** by Diego Zviovich
> https://community.wolfram.com/groups/-/m/t/2075883
> **Phase transition of a SIR agent-based models** by Diego Zviovich
> https://community.wolfram.com/groups/-/m/t/1977230
> **A simple estimate of covid-19 fatalities based on past data** by Kay Herbert
> https://community.wolfram.com/groups/-/m/t/1959438
> **SIR Model with Log-normal infected periods** by Diego Zviovich
> https://community.wolfram.com/groups/-/m/t/1946292
> **SEI2HR-Econ model with quarantine and supplies scenarios** by Anton Antonov
> https://community.wolfram.com/groups/-/m/t/1937880
> **COVID-19 - Policy Simulator - Can you find the perfect policy?** by Jan Brugard
> https://community.wolfram.com/groups/-/m/t/1931352
> **Epidemiological Models for Influenza and COVID-19** by Robert Nachbar
> https://community.wolfram.com/groups/-/m/t/1896178
> **Exploring Epidemiological Modeling** by Jordan Hasler
> https://community.wolfram.com/groups/-/m/t/1920119
> **SEI2HR model with quarantine scenarios** by Anton Antonov
> https://community.wolfram.com/groups/-/m/t/1926505
> **The SIR Model for Spread of Disease** by Arnoud Buzing
> https://community.wolfram.com/groups/-/m/t/1903289
> **COVID-19 - R0 and Herd Immunity - are we getting closer?** by Jan Brugard
> https://community.wolfram.com/groups/-/m/t/1911422
> **Basic experiments workflow for simple epidemiological models** by Anton Antonov
> https://community.wolfram.com/groups/-/m/t/1895675
> **Scaling of epidemiology models with multi-site compartments** by Anton Antonov
> https://community.wolfram.com/groups/-/m/t/1897377
> **WirVsVirus 2020 hackathon participation** by Anton Antonov
> https://community.wolfram.com/groups/-/m/t/1907256
> **An SEIR like model that fits the coronavirus infection data** by Enrique Garcia Moreno
> https://community.wolfram.com/groups/-/m/t/1888335
> **A SEIRD Model For COVID-19 Using DDEs** by Luis Borgonovo
> https://community.wolfram.com/groups/-/m/t/1996374
> **A Neat Package for Compartmental Model Diagrams** by Hamza Alsamraee
> https://community.wolfram.com/groups/-/m/t/2078640
### ________________________________
### EPIDEMIC MODELING: LOGISTIC
> **COVID-19 pandemic data in Italy** by Riccardo Fantoni
> https://community.wolfram.com/groups/-/m/t/1909687
> **Predicting Coronavirus Epidemic in United States** by Robert Rimmer
>https://community.wolfram.com/groups/-/m/t/1906954
> **Tracking Coronavirus Testing in the United States** by Robert Rimmer
> https://community.wolfram.com/groups/-/m/t/1902302
> **Logistic Model for Quarantine Controlled Epidemics** by Robert Rimmer
> https://community.wolfram.com/groups/-/m/t/1900530
> **Updated: coronavirus logistic growth model: China** by Robert Rimmer
> https://community.wolfram.com/groups/-/m/t/1890271
> **Coronavirus logistic growth model: China** by Robert Rimmer
> https://community.wolfram.com/groups/-/m/t/1887435
> **Coronavirus logistic growth model: Italy and South Korea** by Robert Rimmer
> https://community.wolfram.com/groups/-/m/t/1887823
> **Coronavirus logistic growth model: South Korea** by Robert Rimmer
> https://community.wolfram.com/groups/-/m/t/1894561
> **Logistic growth model for epidemic Covid-19 in Colombia** by Diego Ramos
> https://community.wolfram.com/groups/-/m/t/2092786
### ________________________________
### GENOMICS
> **Analyzing the spread of SARS-CoV-2 variants in California** by Daniel Lichtblau
> https://community.wolfram.com/groups/-/m/t/2205357
> **Analyzing the spread of SARS-CoV-2 variants in Florida** by Daniel Lichtblau
> https://community.wolfram.com/groups/-/m/t/2206874
> **Analyzing Nextstrain Data with WFR Newick Functions (COVID-19/SARS-CoV-2)** by John Cassel
> https://community.wolfram.com/groups/-/m/t/1958952
> **Finding and analyzing a COVID subvariant in Australia** by Daniel Lichtblau
> https://community.wolfram.com/groups/-/m/t/2342489
> **Analyzing SARS-CoV-2 Genetic Sequences** by John Cassel & Daniel Lichtblau
> https://blog.wolfram.com/2021/08/19/newick-trees-proximity-resources-and-accessions-analyzing-sars-cov-2-genetic-sequences/
> **Estimating the number of times the SARS CoV-2 virus has replicated** by Carlos Munoz
> https://community.wolfram.com/groups/-/m/t/1943243
>**From sequenced SARS-CoV-2 genomes to a phylogenetic tree** by Daniel Lichtblau
>https://community.wolfram.com/groups/-/m/t/1961461
> **Genome analysis and the SARS-nCoV-2** by Daniel Lichtblau
> https://community.wolfram.com/groups/-/m/t/1874816
> **Visualizing Sequence Alignments from the COVID-19** by Jessica Shi
> https://community.wolfram.com/groups/-/m/t/1875352
> **A walk-through of the SARS-CoV-2 nucleotide Wolfram resource** by John Cassel
> https://community.wolfram.com/groups/-/m/t/1887456
> **Geometrical analysis of genome for COVID-19 vs SARS-like viruses** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1878824
> **Chaos Game For Clustering of Novel Coronavirus COVID-19** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1875994
### ________________________________
### DATA ANALYSIS
> **COVID-19 - The Swedish Experiment - Is it working?** by Jan Brugard
> https://community.wolfram.com/groups/-/m/t/1974412
> **A simple COVID-19 spread model** by Daniel Lichtblau
> https://community.wolfram.com/groups/-/m/t/1945196
> **COVID19: The performance of the Swedish strategy** by Christos Papahristodoulou
> https://community.wolfram.com/groups/-/m/t/1990972
> **Exploring social trends on Covid-19 pandemic using WikipediaData** by Jofre Espigule-Pons
> https://community.wolfram.com/groups/-/m/t/1931508
> **Google Mobility Data** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1946686
> **Understanding Aggregate COVID Curves** by Christopher Wolfram
> https://community.wolfram.com/groups/-/m/t/2068457
> **Apple mobility trends data visualization** by Anton Antonov
> https://community.wolfram.com/groups/-/m/t/1942813
> **Computing COVID-19 Spread Rates in US Cities** by Daniel Lichtblau
> https://community.wolfram.com/groups/-/m/t/1930261
> **COVID-19 data and the Newcomb Benford Distribution** by Gustavo Delfino
> https://community.wolfram.com/groups/-/m/t/1913908
> **Short-time trends for COVID-19**, by Fabian Wenger
> https://community.wolfram.com/groups/-/m/t/1912710
> **What countries are hit hard by COVID19 outbreak?** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1904507
> **COVID19 in Iran: under-diagnosis issue** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1891140
> **Coronavirus analysis: descriptive statistics with SQL functions** by Damian Calin
> https://community.wolfram.com/groups/-/m/t/2206078
> **Argentina: COVID-19 Data Analysis** by Tobias Canavesi
> https://community.wolfram.com/groups/-/m/t/1932910
> **Analysis of the Change in Phillips Curve After COVID-19 with Regression** by Seojin Yoon
> https://community.wolfram.com/groups/-/m/t/2055704
> **COVID wave alert: statistical analysis and visualization** by Antonio Neves
> https://community.wolfram.com/groups/-/m/t/2115658
> **Predicting COVID-19 using cough sounds classification** by Siria Sadeddin
> https://community.wolfram.com/groups/-/m/t/2166833
> **Covid-19 vaccination data analysis using SQL functions** by Damian Calin
> https://community.wolfram.com/groups/-/m/t/2324474
> **Analyzing COVID-19 vaccine sentiment over time** by Arshaan Sayed
> https://community.wolfram.com/groups/-/m/t/2317293
> **VAERS data analysis using SQL functions** by Damian Calin
> https://community.wolfram.com/groups/-/m/t/2351726
> **Correlating COVID-19 government measures to biweekly/daily outbreaks** by Arshaan Sayed
> https://community.wolfram.com/groups/-/m/t/2362327
### ________________________________
### DATA VISUALIZATIONS
> **CDC COVID19 vaccination data across US counties** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/2282418
> **Top 20 COVID countries HeatMap by absolute death and death in ppm** by Rodrigo Murta
> https://community.wolfram.com/groups/-/m/t/2004800
> **US Counties COVID-19 confirmed cases by population density timelines** by Bob Sandheinrich
> https://community.wolfram.com/groups/-/m/t/1992898
> **3D Modeling of the SARS-CoV-2 Virus in the Wolfram Language** by Jeff Bryant
> https://community.wolfram.com/groups/-/m/t/1989540
> **California COVID19 Data** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/2132204
> **COVID-19 progress in Peru macro regions: coast vs mountain vs jungle** by Francisco Rodríguez
> https://community.wolfram.com/groups/-/m/t/1965079
> **COVID-19 reopening criterion: a simple visualization** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1962615
> **100 Days of COVID19 Over US Counties** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1956368
> **Population Density Map** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1955760
> **Google Mobility Data** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1946686
> **COVID19 Case-Fatality Ratio, Income, and Age: Simple Visualization** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1939045
> **Data Analysis of Coronavirus in Mexico** by Ivan Martinez
> https://community.wolfram.com/groups/-/m/t/1927657
> **Confirmed COVID-19 Cases in Catalonia** by Bernat Espigulé Pons
> https://community.wolfram.com/groups/-/m/t/1919468
> **Distance to nearest confirmed US COVID-19 case** by Chip Hurst
> https://community.wolfram.com/groups/-/m/t/1911583
> **COVID19 Confirmed Cases: US Counties** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/1950980
> **COVID19 data visualization across US counties** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/2119049
> **Maps for Visualizing Covid-19's Effect** by Eric Mockensturm
> https://community.wolfram.com/groups/-/m/t/1934457
> **US Counties COVID-19 deaths plot** by Bob Sandheinrich
> https://community.wolfram.com/groups/-/m/t/1918332
> **Comparing the spread of COVID-19 between countries**, Jan Brugard
> https://community.wolfram.com/groups/-/m/t/1905992
> **NY Times COVID-19 data visualization** by Anton Antonov
> https://community.wolfram.com/groups/-/m/t/1911668
> **COVID-19 cases for each administrative division in Spain** by Bernat Espigulé Pons
> https://community.wolfram.com/groups/-/m/t/1910116
> **Propagation risk of COVID-19 by local contact in Spain (10 - 14 March)** by Bernat Espigulé Pons
> https://community.wolfram.com/groups/-/m/t/1898126
> **Visualizing the Pandemic Data COVID-19** by Martijn Froeling
> https://community.wolfram.com/groups/-/m/t/1899870
> **COVID-19 visualization of turning point** by Isao Maruyama
> https://community.wolfram.com/groups/-/m/t/1899911
> **Mapping "Live" COVID Data on a Globe** by Gabriel Lemieux
> https://community.wolfram.com/groups/-/m/t/1902102
> **Novel Coronavirus COVID-19 in Brazil** by Estevao Teixeira
> https://community.wolfram.com/groups/-/m/t/1905950
> **Mapping Novel Coronavirus COVID-19 Outbreak** by Jofre Espigule-Pons
> https://community.wolfram.com/groups/-/m/t/1868945
> **Ways to visualize COVID-19 simulation results?** by Kyle Keane
> https://community.wolfram.com/groups/-/m/t/1962739
> **General and COVID-19 deaths in Sweden** by Oscar Rodriguez
> https://community.wolfram.com/groups/-/m/t/2006377
> **COVID19 Tokyo per days of the week** Isao Maruyama
> https://community.wolfram.com/groups/-/m/t/2133807
### ________________________________
### DATA PROCESSING
> **Cov-Tell: Daily COVID-19 Updates with Alexa (made with Wolfram APIFunction)** by Jessica Shi
> https://community.wolfram.com/groups/-/m/t/1958307
> **Build a COVID-19 Chest X-Ray Image Uploader with Cloud & Data Drop** by Jofre Espigule-Pons
> https://community.wolfram.com/groups/-/m/t/1919770
> **Scraping OpenTable's "State of the Industry" page** by Aaron Enright
> https://community.wolfram.com/groups/-/m/t/1911043
> **City-level Search Tool for Coronavirus (COVID-19) Confirmed Cases** by David Lomiashvili
> https://community.wolfram.com/groups/-/m/t/1913247
> **Web Scraper: New York Times Coronavirus Data** by Robert Rimmer
> https://community.wolfram.com/groups/-/m/t/1894426
> **TraCOV: Personalized COVID-19 Risk Analysis Tool** by Jessica Shi
> https://community.wolfram.com/groups/-/m/t/1977700
> **Mobility changes data: transforming to Wolfram Language dataset** by Mads Bahrami
> https://community.wolfram.com/groups/-/m/t/2160386
### ________________________________
### MASKS
> **Effect of mandatory mask usage in COVID cases** by Diego Zviovich
> https://community.wolfram.com/groups/-/m/t/1919060
> **Face mask detection: classifying image data** by Siria Sadeddin
> https://community.wolfram.com/groups/-/m/t/2139499
## ________________________________________
## [Livestream Archives (*link*)][18]
- Stephen & Christopher Wolfram + guests [Exploring Pandemic Data][19]
- Stephen & Christopher Wolfram + guests [Exploring and Explaining Epidemic Modeling][20]
- Robert Nachbar - [Epidemiological Models for Influenza and COVID-19][21]
- Brian Wood - [COVID-19 Dashboard Visualizations][22]
- John Cassel - [Behind the Genetic Sequences for Novel Coronavirus SARS-CoV-2][23]
- Keiko Hirayama - [Patient Data Exploration for the Novel Coronavirus COVID-19][24]
- Keiko Hirayama - [Pandemic Data Exploration for the Novel Coronavirus COVID-19][25]
- Diego Zviovich - [Geo-spatial-temporal COVID-19 Simulations and Visualizations Over USA][26]
- Anton Antonov - [COVID19 Epidemic Modeling: Compartmental Models][27]
- Anton Antonov - [Scaling of Epidemiology Models with Multi-site Compartments][28]
- Anton Antonov - [Simple Economic Extension of Compartmental Epidemiological Models][29]
- Juan Klopper - [Coronavirus medical data analysis][30]
- Juan Klopper - [Coronavrirus epidemiological data analysis][31]
- Rory Foulger - [Coronavirus Data Exploration - Wolfram Livecoding with Students][32]
## ________________________________________
## Other useful resources
- Arnoud Buzing [GitHub][33] repository and [Notebook Gallery][34] for coronavirus
- [Modeling a Pandemic like Ebola with the Wolfram Language](https://blog.wolfram.com/2014/11/04/modeling-a-pandemic-like-ebola-with-the-wolfram-language)
- [Epidemics at Wolfram Demonstrations](https://demonstrations.wolfram.com/search.html?query=epidemic)
- [IGSIRProcess - IGraph Epidemic models][35]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=1China_c.png&userId=1624544
[2]: https://community.wolfram.com//c/portal/getImageAttachment?filename=1.5US_c.png&userId=1624544
[3]: https://community.wolfram.com//c/portal/getImageAttachment?filename=2World_c.png&userId=1624544
[4]: https://community.wolfram.com//c/portal/getImageAttachment?filename=3Genetic_c.png&userId=1624544
[5]: https://community.wolfram.com//c/portal/getImageAttachment?filename=4Patient_c.png&userId=1624544
[6]: https://community.wolfram.com//c/portal/getImageAttachment?filename=5Resources_c.png&userId=1624544
[7]: https://www.wolframcloud.com/obj/examples/COVID19Preview.png
[8]: https://www.wolframcloud.com/obj/s.wolfram/Published/COVID-19-Livestream-March-24.nb
[9]: https://community.wolfram.com/groups/-/m/t/1907703
[10]: https://youtu.be/Vs5APySGYnk
[11]: https://youtu.be/kC6LHAv_lx0
[12]: https://community.wolfram.com/groups/-/m/t/1908923
[13]: https://datarepository.wolframcloud.com/search/?i=COVID-19
[14]: https://datarepository.wolframcloud.com/search/?i=COVID-19
[15]: https://reference.wolfram.com/language/workflow/SubmitToTheWolframDataRepository.html
[16]: https://community.wolfram.com/groups/-/m/t/2238214
[17]: http://wolfr.am/StaffPicks
[18]: https://www.youtube.com/playlist?list=PLxn-kpJHbPx3_hUbroRYC_7NxcOwZ1SWa
[19]: https://youtu.be/Vs5APySGYnk
[20]: https://youtu.be/kC6LHAv_lx0
[21]: https://youtu.be/pcFB6_yrxGE
[22]: https://youtu.be/vUq8qx7kTYA
[23]: https://youtu.be/HCJgv3N_kDo
[24]: https://youtu.be/MlI_8o4A3BA
[25]: https://youtu.be/P86ZY-znE64
[26]: https://youtu.be/Kjk-sYlg-U0
[27]: https://youtu.be/LRs9rYCXIzs
[28]: https://youtu.be/b8oCNjRI0gY
[29]: https://youtu.be/C-sjXQiPE7s
[30]: https://youtu.be/gA0TPQZgNY0
[31]: https://youtu.be/I-n3zN4aU6c
[32]: https://youtu.be/4xCfPIiredM
[33]: https://github.com/arnoudbuzing/wolfram-coronavirus
[34]: https://wolfr.am/JZNRriEE
[35]: http://szhorvat.net/mathematica/IGDocumentation/#epidemic-modelsVitaliy Kaurov2020-02-04T15:18:14ZRLink on a silicon Mac?
https://community.wolfram.com/groups/-/m/t/2357607
I tried using RLink today on a new silicon Mac. The silicon (ARM) version of R is installed and works. When I run InstallR[] I get the following cryptic error message. "InstallR::bndlunsupp: RLink does not support bundled R runtime for the current platform. Please use externally installed R distribution"
Ok. How?? I've looked at the RLink documentation and it discusses a "TargetPlatform" option, but it is not a model of clarity and does not provide examples.Seth Chandler2021-09-01T15:27:22ZHow can I turn a system of equations into a matrix?
https://community.wolfram.com/groups/-/m/t/2366895
Hello!
I'm working on a program using Wolfram Mathematica that can give us the exponential matrix as a result. I have a 3x3 system as a base (but it may work with a nxn one), which gives me 3 linear equations that involve alphas and lambdas with their respective "t's". So far, I don't know how to turn that system into a matrix to get this form: **e^( λi) = A* α** . I would like to know if there is a way where I can take those α's away from my equations (attached image) and put them into an independent vector, so I can proceed to to this: **α = A^-1 * e^( λi)**; "A" would be the matrix formed from the Eigenvalues and alphas polynomial equation showed below.
I would appreciate if you could help me with this situation.
Greetings!
P.S. I'm not allowed to use any shortcut like Solve or Matrix Exp.
![image][1]
Thank you!
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=ForoWolfram.jpg&userId=2366880Karla Reyes Lomelí2021-09-15T00:55:46ZCOVID-19 - the Swedish experiment - is it working?
https://community.wolfram.com/groups/-/m/t/1974412
*MODERATOR NOTE: coronavirus resources & updates:* https://wolfr.am/coronavirus
----------
![enter image description here][1]
&[Wolfram Notebook][2]
[Old]: https://www.wolframcloud.com/obj/c29137dd-dcdf-4dd1-827e-3495b64a8436
[Original]: https://www.wolframcloud.com/obj/a9d60a60-4adf-41ec-ad5a-a666b1591cf0
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=image.jpeg&userId=20103
[2]: https://www.wolframcloud.com/obj/956d65fd-abfb-45d9-802d-9a79013e7b14Jan Brugard2020-05-14T15:04:02ZLife, Liberty, and Lockdowns: cellular automaton approach
https://community.wolfram.com/groups/-/m/t/2181433
*MODERATOR NOTE: coronavirus resources & updates:* https://wolfr.am/coronavirus
----------
*SUPPLEMENTARY MATERIALS for the ARTICLE:*
> Philip Z. Maymin and Zakhar G. Maymin (2021). *Life, Liberty, and Lockdowns.*
> Covid-19: A Complex Systems Approach p.109-120. STEM ACADEMIC PRESS.
> ISBN-13: 978-0578912004 ISBN-10: 0578912007
> JOURNAL: https://stemacademicpress.com/stem-volumes-covid-19
> AMAZON: https://www.amazon.com/dp/0578912007
> [Full volume PDF][1]
&[Wolfram Notebook][2]
[1]: https://img1.wsimg.com/blobby/go/154a8d95-e8e0-4947-990b-6ba07b203d97/downloads/STEM_Covid%20%2818%29.pdf?ver=1621257600555
[2]: https://www.wolframcloud.com/obj/61cde30d-845b-4961-ba0b-692ab04fb28ePhilip Maymin2021-02-01T18:06:31ZOptimal climate policy: behind the scenes solving ODEs model
https://community.wolfram.com/groups/-/m/t/2255854
*SUPPLEMENTARY WOLFRAM MATERIALS for ARTICLE:*
> Charles F. Manski, Alan H. Sanstad, and Stephen J. DeCanio
> "Addressing partial identification in climate modeling and policy analysis".
> Proceedings of the National Academy of Sciences, Vol 118, No. 15 (2021)
> https://doi.org/10.1073/pnas.2022886118
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/79b1a40f-2a7e-4e46-b5be-e171b3702b15Stephen DeCanio2021-04-28T17:35:05ZSpeed up FindRoot for system of equations
https://community.wolfram.com/groups/-/m/t/2367061
Hello,
I'm solving a system of m by m equations in two variants. When m=7, the second system takes me approximately 15 seconds. Since I want to solve a more complex system for much larger m, I'm looking for any help on speeding up the solution.
Thanks!
In[34]:= Clear[PPi, pi, m, n, TT, T, TT0, T0, NN, n0, N0, A, R, e];
m = 7;
v[i_, j_] := A[j] Sum[n[k, j], {k, m}]/Sum[n[i, l], {l, m}]
PPi = Table[pi[i, j], {i, m}, {j, m}];
pi[i_, j_] := T[i, j] v[i, j]^(e)/Sum[T[k, l] v[k, l]^e, {k, m}, {l, m}];
In[39]:= btab = Table[RandomReal[{1, 1.2}], {j, m}];
A[j_] := btab[[j]]
R = Table[RandomReal[], {i, m}, {j, m}];
n0[i_, j_] := R[[i, j]]/Total[Flatten[R]]
In[43]:= Clear[T, TT, TTm, n, NN, NNm];
N0 = Table[n0[i, j], {i, m}, {j, m}];
TT0 = Table[1, {i, m}, {j, m}];
T0[i_, j_] := TT0[[i, j]]
TT = Table[T[i, j], {i, m}, {j, m}];
NN = Table[n[i, j], {i, m}, {j, m}];
NNm = Drop[Flatten[NN], -1];
NNm0 = Drop[Flatten[N0], -1];
TTm = Drop[Flatten[TT], -1];
TTm0 = Drop[Flatten[TT0], -1];
In[53]:= newmat = Drop[Flatten[PPi - NN], -1];
In[54]:= (* baseline: solve for T given n for given e*)
Clear[T, n];
e = 5;
n[i_, j_] := N0[[i, j]]
T[m, m] = 1;
soln1 = FindRoot[{newmat},Transpose[{Flatten[{TTm}], Flatten[{TTm0}]}]] // AbsoluteTiming;
%[[1]]
Out[59]= 0.500039
In[60]:= TT = TT /. soln1[[2]];
T[i_, j_] := TT[[i, j]]
In[62]:= (* new eq : solve for n given T with new e value *)
e = 3;
Clear[NN, n];
n [m, m] = 1 - Total[NNm];
soln2 = FindRoot[{newmat},Transpose[{Flatten[{NNm}], Flatten[{NNm0}]}]] // AbsoluteTiming;
%[[1]]
Out[66]= 14.5182Rainald Borck2021-09-15T19:46:06Z[WSS21] Bell's equation in The Wolfram Model multiway formalism
https://community.wolfram.com/groups/-/m/t/2315046
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/e4b5aa2e-3dac-4552-ae41-856044dd0f00Mark Merner2021-07-14T15:22:06ZReal, complex, and infinite results from Integrate[] for like inputs
https://community.wolfram.com/groups/-/m/t/2367151
I've been working with Mathematica for symbolic calculations, primarily Integrations.
The following is a function I am trying to integrate with the shown assumptions:
Integrate[(50 (0.000258748 + 0.117362 Vch^2) (23 + (84 Vch)/Sqrt[
1 + 776.46 Vch^2]) (1 + (
0.76354 (2 + 2329.38 Vch^2 + 1.20578*10^6 Vch^4))/(1 +
776.46 Vch^2)^(3/2)))/(1 + Vch^2), Vch, Assumptions -> {Vch != 0, Element[{Vch}, Reals]}]
However, I am getting various results for the output of the function depending on multiple criteria:
1)If I expand the above function before applying it to Integrate[], I get 1/0^2 infinity errors.
2) If I do not expand the function and leave it as shown above, the result are complex numbers
3) If I expand the above function and manually integrate each term (since the terms are added to each other) I will get a real result, which is what it should be.
I have to take multiple integrals similar to the one above. Taking each term after the expansions and Integrating each one is fine, but I think it's a roundabout solution.
Does anyone have any ideas as to what is happening and what steps I could take to get a real solution?
Thanks!John Mappes2021-09-15T15:58:06ZComplete definitions: graphing how words and definitions connect
https://community.wolfram.com/groups/-/m/t/2358728
*WOLFRAM MATERIALS for:*
> Dorner Prize from RISD Museum (Rhode Island School of Design)
> Announcement: https://risdmuseum.org/exhibitions-events/exhibitions/complete-definitions
> Exhibition: https://publications.risdmuseum.org/complete-definitions
![enter image description here][1]![enter image description here][2]
![enter image description here][3]
&[Wolfram Notebook][4]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=test3_16_9_21.gif&userId=20103
[2]: https://community.wolfram.com//c/portal/getImageAttachment?filename=test6_16_9_21-min.gif&userId=20103
[3]: https://community.wolfram.com//c/portal/getImageAttachment?filename=hero1.jpg&userId=20103
[4]: https://www.wolframcloud.com/obj/c673004d-1f56-4de2-a667-032fcb5dce70Jack Madden2021-09-02T23:27:42ZTotal Derivative error
https://community.wolfram.com/groups/-/m/t/2367219
Hi does anyone know why my total derivative command isn't working? I've never encountered this error message before.
![enter image description here][1]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=mathematicabullshit.PNG&userId=2276986Nikolas Kwok2021-09-15T12:18:34ZAccessing mySQL database using DatabaseReference[ ]?
https://community.wolfram.com/groups/-/m/t/2364078
Hi All,
I'm struggling to understand the best way to access a mySQL database. I would like to execute SQL commands but just cant seem to get it to work.
I use the following approach via entitystore;
connectionMYSQL =
DatabaseReference[{"Backend" -> "mysql", "Port" -> 3306,
"Host" -> "localhost", "Username" -> "root", "Password" -> "",
"Name" -> "socialdata"}]
rdb = RelationalDatabase@connectionMYSQL
es = EntityStore@rdb
I can see the tables in EntityStore but trying to get data via EntityValue doesn't seem to work.
The following fails:
EntityValue["table1", {"col1", "col2....
The other way of doing this is:
conn = DatabaseReference[
URL["mysql://root@localhost:3306/socialdata"]]
SQLExecute[conn, "SELECT * FROM ....
which does not work!
Ideally I would like to execute SQL commands. are there any good examples showing this working (especially for a local database)?S G2021-09-10T10:39:51ZMnemonic conversion between kilometers and miles using Fibonacci ratios
https://community.wolfram.com/groups/-/m/t/2366694
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/c18fb267-3634-4a6e-8bbc-d8d49d4616fbBill Gosper2021-09-14T16:52:14ZDisplay polynomial retaining MonomialList[ ] order?
https://community.wolfram.com/groups/-/m/t/2366454
MonomialList is a neat functions for rearranging a polynomial, but if you convert it back to a polynomial with Total[] or Plus[], the output reverts to the default lexicographic order, which sabotages the functionality of MonomialList[]. Is there a way to rearrange a polynomial according to MonomialList[] options? By that, I mean a way that's easier than editing the list back into a polynomial character by character?
For example:
Say you have a polynomial like 4 x y^2 z + 4 z^2 - 5 x^3 + 7 x^2 z^2 and want to display it three different ways -- Lexicographic order, DegreeLexicographic order and NegativeDegreeLexicographic order.Jay Gourley2021-09-14T02:12:23ZThe reciprocal Fibonacci constant
https://community.wolfram.com/groups/-/m/t/2365201
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/f4c3bd95-fcd4-4bb1-9dca-93f43c9e9ee0Jonathan Kinlay2021-09-11T09:38:30ZHow to draw several contours label in separate colors?
https://community.wolfram.com/groups/-/m/t/2362787
Good morning. I have two equations (or more) that I want plot with ContourPlot colored with different colours and labelled according to equation order, in a automatic way. I have tried several solutions without success. My plot should remain as
g1 = x + 2 y; g2 = 2 x + y; b = {2, 2};
coloresRest = {Blue, Magenta}; labelRest =
Table[Text[Style["(" <> ToString@i <> ")", coloresRest[[i]]]], {i,
Length@coloresRest}];
ContourPlot[{g1 == b[[1]], g2 == b[[2]]}, {x, -2,
4}, {y, -2, 4}, Frame -> False, Axes -> True,
ContourStyle -> Thread[{coloresRest, grosor}],
Epilog -> {Text[Style["(1)", color3], Offset[{20, 0}, {-2, 2}]],
Text[Style["(2)", color4], Offset[{-10, -10}, {-1, 4}]]},
ImageSize -> 400]
![enter image description here][1]
I have tried with Table, ContourLabel, Riffle or Epilog, without success. For example:
ContourPlot[{g1 == b[[1]], g2 == b[[2]]}, {x, -2,
4}, {y, -2, 4}, Frame -> False, Axes -> True,
ContourStyle -> Thread[{coloresRest, grosor}],
ContourLabels ->
Table[Text[Style[labelRest[[i]], Offset[{10, 0}, {#1, #2} &]]], {i,
1, Length@coloresRest}], ImageSize -> 400]
or
ContourPlot[{g1 == b[[1]], g2 == b[[2]]}, {x, -2,
4}, {y, -2, 4}, Frame -> False, Axes -> True,
ContourStyle -> Thread[{coloresRest, grosor}],
ContourLabels -> {Riffle[coloresRest,
Inset[labelRest, Offset[{10, 0}, {#1, #2} &]]]}, ImageSize -> 400]
I realize that expression {#1, #2}& yield coordinates for labels, chosen by Mathematica. I'd prefer that and not to choose such coordinates.
Thank in advance
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=ContourLabelparapreguntacomunidadWolfram.jpg&userId=1867172Rafael Rodriguez2021-09-09T08:28:50ZSolve[ ] gives an empty output?
https://community.wolfram.com/groups/-/m/t/2362911
Hello, I need c1,c2....c9 values. Why is Solve returning an empty list?
How I can fix it? Thanks for any advice.
Solve[{uj == aj*c1 + bj*c2 + cj*c3 + ui,
vj == aj*c4 + bj*c5 + cj*c6 + vi, tj == aj*c7 + bj*c8 + cj*c9 + ti,
uk == ak*c1 + bk*c2 + ck*c3 + ui, vk == ak*c4 + bk*c5 + ck*c6 + vi,
tk == ak*c7 + bk*c8 + ck*c9 + ti, ul == al*c1 + bl*c2 + cl*c3 + ui,
vl == al*c4 + bl*c5 + cl*c6 + vi, tl == al*c7 + bl*c8 + cl*c9 + ti,
um == am*c1 + bm*c2 + cm*c3 + ui, vm == am*c4 + bm*c5 + cm*c6 + vi,
tm == am*c7 + bm*c8 + cm*c9 + ti, un == an*c1 + bn*c2 + cn*c3 + ui,
vn == an*c4 + bn*c5 + cn*c6 + vi, tn == an*c7 + bn*c8 + cn*c9 + ti,
uo == ao*c1 + bo*c2 + co*c3 + ui, vo == ao*c4 + bo*c5 + co*c6 + vi,
to == ao*c7 + bo*c8 + co*c9 + ti, up == ap*c1 + bp*c2 + cp*c3 + ui,
vp == ap*c4 + bp*c5 + cp*c6 + vi,
tp == ap*c7 + bp*c8 + cp*c9 + ti}, {c1, c2, c3, c4, c5, c6, c7, c8,
c9}]Umut Cemre Can2021-09-09T09:27:27ZAnimating Mathematica surfaces: Wolfram and Blender integration 5
https://community.wolfram.com/groups/-/m/t/2366292
![enter image description here][1]![enter image description here][2]
&[Wolfram Notebook][3]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=8129imageGif1.gif&userId=20103
[2]: https://community.wolfram.com//c/portal/getImageAttachment?filename=2208imageGif2.gif&userId=20103
[3]: https://www.wolframcloud.com/obj/8ea43d6f-9377-46ad-8d4d-5c361a2c18bbGuenther Gsaller2021-09-13T15:01:56Z[WSG21] Daily Study Group: programming tutorials
https://community.wolfram.com/groups/-/m/t/2330900
Daily Study Groups are back, now providing expertise on practical programming! After a short break, we're starting up with a series that picks up where Wolfram Language Basics sessions ended. This 3-week series will take you from basic programming concepts to package development.
Need tips on improving your code’s speed or functionality? Programming Tutorials offer a great opportunity to level-up your skills while interacting with software development professionals. See hands-on examples and get questions answered by Wolfram Language experts. Plus: participants who pass weekly quizzes are awarded a program completion certificate. Level 1 certification is available for those who pass manually graded exercises.
Join us any time between August 2 and August 20! Check out our [registration page][1] for more details.
[1]: https://wolfr.am/Study_Group15Wolfram U2021-07-30T15:24:02ZInternal self-test errors
https://community.wolfram.com/groups/-/m/t/2278697
I keep running into internal self-test errors, e.g. if I use Free-form input and type
"= caffeine molecule" and then click on the + to show all results.
The scrollbar starts vibrating and the notebook is completely stuck. Sometimes it throws an internal self-test error with the file DXScreenGraphics.cpp.
I'm running Mathematica 12.3 on Windows 10.
![error messages][1]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=error.png&userId=2278221Andreas Dumont2021-05-29T11:26:52ZWolfram Neural Net Repository (WNNR) and model discussions
https://community.wolfram.com/groups/-/m/t/2360563
I am a developer in the machine learning team, and mostly involved with the neural net repository. One of the discussions with my group raised these question in my mind, and these might be stupid questions, but here they are:
Question 1: Would our users rather want more models in their respective field of applications, that are correct, functioning and tested, or would they want models that are correct, functioning tested and properly structured? In other words, a lot of the times, models when imported are not structured properly, and many a times we spend a great deal of time restructuring them (in lack of better words, prettifying them).
If I were a user, I would rather have more models that are correct and ugly, rather than less models that are correct and pretty, because a great deal of developer time is spent in "prettifying them". However, the question to the users here, is there any potential benefit of having a pretty model as opposed to an ugly one, that could justify endless developer hours being spent on making a model pretty? I maybe missing some details or use of pretty and structured models here, and that's why I reached out to our community to see if there are any advantages to justify the tradition of making the published models pretty. This would potentially help us free some time to actually convert models for various application areas.
Here's a more concrete example of pretty v/s ugly:
https://drive.google.com/drive/folders/1bnrN4xELVGNObxwSMrnvijBcm_bU2V0P?usp=sharing
Please import the models to learn about the pretty and ugly versions (there are other differences). The .onnx has only the backbone and the FPN (you can verify that the output are the 4 probabilities and box locs). A first-level restructuring where relevant sections are marked backbone, FPN and the rest of the sections would not take much time, but to prettify it to the full, would require a lot of restructuring. For practical purposes, one would simply want to extract the relevant sections like backbone and/or BiFPN for further uses.
Question 2: That also brings me to the next topic, how important are each of these sections in the main page you see for the models in the WNNR? https://resources.wolframcloud.com/NeuralNetRepository/resources/EfficientNet-Trained-on-ImageNet-with-AdvProp-and-AutoAugment/
e.g. If someone could rank the usefulness of each section of the above shingle page, starting from "Resource Retrieval" to "Export to MXNet" that would be great as well.
Question 3: Would you prefer seeing more sections in such shingle pages? Sections explaining the architecture, like they do in the original research papers? If so, any ideas for how it should look/be formatted? How much details should each shingle page have?
P.S. All the groups tagged here are relevant application areas of the WNNR.Tuseeta Banerjee2021-09-06T17:55:20ZEstimating parameters of a stable distribution
https://community.wolfram.com/groups/-/m/t/2364156
Hi! I tried to estimated a stable distribution from the dataset hereunder.
don = {-0.03394489884326527`, -0.03394489884326527`, \
-0.03394489884326527`, 0.017575499123739236`, -0.02922087436589889`,
0.010555301952384558`, -0.0004591035505102574`, \
-0.010672854855081883`, -0.010672854855081883`, \
-0.010672854855081883`, -0.08128446482267304`,
0.0032508155059952823`, -0.02538460889511576`, \
-0.024967155569905922`, -0.03200434753397141`, -0.03200434753397141`, \
-0.03200434753397141`, 0.06752654532202125`, -0.05355714737031551`,
0.023927179959644322`, -0.01692677371352175`, 0.004213861657695463`,
0.004213861657695463`, 0.004213861657695463`, 0.06477832885486146`,
0.047395621108916`, -0.013796405278464848`,
0.017297775562395895`, -0.0156695124441822`, -0.0156695124441822`, \
-0.0156695124441822`, 0.015427766859393002`, -0.07003501198980705`,
0.022493946849797`, -0.010375566995092983`, 0.018904524972064116`,
0.018904524972064116`, 0.018904524972064116`, 0.010076845370000675`,
0.007618949872832066`, -0.016456882934399578`,
0.007208123141758686`, 0.011401391548995866`, 0.011401391548995866`,
0.011401391548995866`, -0.0253288097675204`, \
-0.058520237459744974`, -0.02375294625331719`, 0.017375496159210194`,
0.034068174572563635`, 0.034068174572563635`, 0.034068174572563635`,
0.027290444945758614`,
0.04156935324646256`, -0.003750649699042637`,
0.037454954921030306`, -0.09162567061098696`, \
-0.09162567061098696`, -0.09162567061098696`, 0.10097428521409842`,
0.06268162221233843`, -0.010062863532103786`, \
-0.011450360453901243`, 0.023602452463382263`, 0.023602452463382263`,
0.023602452463382263`, 0.051080593533900966`, 0.013565832731434217`,
0.0023202018721298267`, -0.02578344291194117`, \
-0.003982473432848802`, -0.003982473432848802`, \
-0.003982473432848802`, 0.021815347172571033`,
0.05031452199325336`, -0.006703957641941638`, \
-0.012443436269867542`, 0.0018818646288593615`,
0.0018818646288593615`,
0.0018818646288593615`, -0.029845016829764696`,
0.04160475193396266`, -0.005227759187617618`, 0.005939136002577116`,
0.008100174424780083`, 0.008100174424780083`,
0.008100174424780083`, -0.011169013468163798`, \
-0.008258286074726324`,
0.012235814625092312`, -0.0219780557330319`, \
-0.018525610718695348`, -0.018525610718695348`, \
-0.018525610718695348`, 0.010313197133002959`,
0.01652889231101857`, -0.006807824169006668`, -0.00916036980725222`,
0.005692639452927531`, 0.005692639452927531`,
0.005692639452927531`, -0.05865805690492846`, 0.030007756501598502`,
0.047866401371804805`, 0.009191211435466534`,
0.009191211435466534`, 0.009191211435466534`, 0.009191211435466534`,
0.012704204855465558`, -0.004374802694069071`,
0.006159405798702674`, 0.010398007713170057`, 0.010398007713170057`,
0.010398007713170057`,
0.010398007713170057`, -0.005407391955942583`, \
-0.01425961090609437`, 0.05396061417482968`,
0.0075523767867888125`, -0.004829312771382072`, \
-0.004829312771382072`, -0.004829312771382072`, \
-0.011867336746311232`, 0.036002650842475184`,
0.03631654440886033`, -0.0032531650183932883`, 0.02381710046507902`,
0.02381710046507902`, 0.02381710046507902`,
0.013162035573157968`, -0.007896429640234936`,
0.001261888587978409`, -0.004754391454896683`, \
-0.0015872621812589682`, -0.0015872621812589682`, \
-0.0015872621812589682`, -0.023724470246995304`,
0.038136912638033475`, -0.022044653284554773`,
0.009806991072314142`, -0.012167821949641078`, \
-0.012167821949641078`, -0.012167821949641078`, 0.029822985875977166`,
0.022471874318293367`, 0.012297578413894355`,
0.013317501793784084`, 0.023974565929419284`, 0.023974565929419284`,
0.023974565929419284`, 0.06432436525081472`, 0.`,
0.07081869836272542`, 0.0012540446542990394`,
0.0032500028610229492`, 0.0032500028610229492`,
0.0032500028610229492`, -0.0012515931374596837`,
0.0012500286102294922`,
0.01234572552595136`, -0.007212206652050459`, 0.009361938080480808`,
0.009361938080480808`, 0.009361938080480808`,
0.00024628757015877857`, -0.006445221468641928`,
0.0032122588743909337`,
0.0004939133482378811`, -0.0032210139170059915`, \
-0.0032210139170059915`, -0.0032210139170059915`,
0.003702874076738646`, 0.0068643976356639125`,
0.014734268663654605`, -0.01272016831139334`,
0.0014655696538679252`, 0.0014655696538679252`,
0.0014655696538679252`,
0.0067929047282415875`, -0.0046307708131043636`,
0.0017031555365026954`, -0.0029282781303375826`,
0.0009751795927657461`, 0.0009751795927657461`,
0.0009751795927657461`, -0.010344900079711672`, \
-0.002469074462651643`,
0.0046693481580596325`, -0.000245803235037827`, \
-0.004940706922891259`, -0.004940706922891259`, \
-0.004940706922891259`,
0.00024695667411894057`, -0.0012363099455563766`, \
-0.0009901452866180843`,
0.0004947687115533803`, -0.0014866308960014083`, \
-0.0014866308960014083`, -0.0014866308960014083`, \
-0.0034808402625094177`, 0.007403802929277001`,
0.007349273541704096`, -0.00024502022965067265`, \
-0.00024502022965067265`, -0.00024502022965067265`, \
-0.00024502022965067265`, -0.00024502022965067265`, \
-0.008899820581918147`,
0.0004941574191833465`, -0.004218292963291941`,
0.0004959957860462927`, 0.0004959957860462927`,
0.0004959957860462927`, 0.0014858944534322119`, 0.`,
0.007618496501533813`, -0.004443260558482116`,
0.0022167055790065743`, 0.0022167055790065743`,
0.0022167055790065743`,
0.0019665430969144602`, -0.00394861644264421`,
0.0004933041663618312`, -0.00024671293544038965`, 0.`, 0.`, 0.`,
0.003442325858585361`, 0.002941918101143018`,
0.002201522729608241`, -0.003190187006766056`, \
-0.00270661397991699`, -0.00270661397991699`, -0.00270661397991699`,
0.000983212940151308`, -0.002217251660530477`,
0.004415041761553593`, -0.0027054000107892325`, \
-0.00024598462648870844`, -0.00024598462648870844`, \
-0.00024598462648870844`, 0.00877829222293795`, 0.009420298451695876`,
0.0024096936510914803`, -0.0031423764032808975`, \
-0.01696171260034035`, -0.01696171260034035`, -0.01696171260034035`,
0.0024522385270853556`, 0.000735060688952018`,
0.00024496020944389947`, 0.00024501697600935783`,
0.0009786420816095091`, 0.0009786420816095091`,
0.0009786420816095091`, -0.001715678826793574`, \
-0.0009812830896425734`, -0.0029527764617041344`, \
-0.0009852677282126817`, -0.0004928178901589532`, \
-0.0004928178901589532`, -0.0004928178901589532`, \
-0.0004930608793812498`,
0.`, -0.00970874593139338`, -0.00970874593139338`, \
-0.0032467559533485603`, -0.0032467559533485603`, \
-0.0032467559533485603`, -0.001000046730041504`, 0.`, 0.`, 0.`, 0.`,
0.`, 0.`, 0.0004997139215246588`, -0.0004999637603759766`, 0.`, 0.`,
0.0007493836435673616`, 0.0007493836435673616`,
0.0007493836435673616`, 0.`, -0.0004998388097305292`, 0.`, 0.`,
0.0004995890957115743`, 0.0004995890957115743`,
0.0004995890957115743`, -0.0007499456405639648`,
0.0002499194048652646`, -0.0002499818801879883`,
0.0029910477747560134`, -0.0027493518125115825`, \
-0.0027493518125115825`, -0.0027493518125115825`,
0.`, -0.0002499818801879883`, 0.`, 0.`, 0.0002499194048652646`,
0.0002499194048652646`, 0.0002499194048652646`, 0.`, 0.`, 0.`, 0.`,
0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`,
0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`,
0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`,
0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`, 0.`,
0.`, 0.`, 0.`}
It seems impossible toe estimate the corresponding parameter : endless computation.
In[459]:= EstimatedDistribution[don,
StableDistribution[\[Alpha], \[Beta], \[Mu], \[Sigma]]]
Out[459]= $Aborted
Probably because an excess of zeroes? Deleting zeroes, it works more or less...
In[460]:= EstimatedDistribution[Select[don, # =!= 0. &],
StableDistribution[\[Alpha], \[Beta], \[Mu], \[Sigma]]]
During evaluation of In[460]:= FindMaximum::cvmit: Failed to converge to the requested accuracy or precision within 100 iterations.
Out[460]= StableDistribution[1, 1.01354, 0.128295, 0.0363144, \
0.00597755]
What should I do to process the whole dataset?
Thanks in advance,
ClaudeClaude Mante2021-09-10T13:54:46ZTry to beat these MRB constant records!
https://community.wolfram.com/groups/-/m/t/366628
The MRB constant: ALL ABOARD!
-----------------------------
POSTED BY: Marvin Ray Burns.
![CMRB][1]
On 9/5/2021 I added the following strange MRB constant integral
![strange][2]
See proof [here][3].
On Pi Day, 2021, 2:40 pm EST,
I added a new MRB constant integral.
![CMRB][4] ![=][5] ![integral to sum][6]
Map:
----
- First, we have formal identities and theory for **C**<sub>*MRB*</sub>.
- Then, at the end of this initial posting, we have world records of the maximum number of digits of **C**<sub>*MRB*</sub>
computations by date.
- Then we have some hints for anyone serious about breaking my record.
- Followed by speed records,
- a program Richard Crandall wrote to check his code for the computing record number of digits
- and a conversation about whether Mathematica uses the same algorithm for computing **C**<sub>*MRB*</sub> by a couple of different methods.
- Then, for a few replies, we compute **C**<sub>*MRB*</sub> from Crandall's eta derivative formulas and see records there.
- There are three replies about "NEW RECORD ATTEMPTS OF 4,000,000 DIGITS!" and the computation is now complete!!!!!.
- We see where I am on a 5,000,000 digit calculation. **(Just recently completed!!!!!!!!!!!!)**
- I describe the MRB supercomputer!!!!!! (faster than some computers with dual platinum Xeon processors) It was used for the 5,000,000 digit calculation.
- Then it comes time for the 6 million digit computation of **C**<sub>*MRB*</sub>. (put on hold, but taken up again at the end)
- We compute **C**<sub>*MRB*</sub> sum via an integral, which certifies the accuracy of **C**<sub>*MRB*</sub> calculations!!!!! (since the sum and integral are vastly different in every way they are computed)
- Then we take up the task of calculating 6,000,000 (6 million) digits of **C**<sub>*MRB*</sub> (for the <s>fourth, fifth time, sixth, seventh time!) (will finish Thu 25 Feb 2021 06:48:06).</s>
- We look for closed forms and find nontrivial, arbitrarily close approximations of **C**<sub>*MRB*</sub>.
- The latest updates on the MRB constant supercomputer 2 (with a GIF of it) and how I'm using it to break new records -- up to 7,500,000 digits -- are in a few replies.
- **On my 8th try I finally report that I successfully computed 6,000,000 digits of **C**<sub>*MRB*** !
- We work at proving the accuracy of my computations.
- For a few replies, we find a few more formulas for **C**<sub>*MRB*,</sub>.
- We take up the challenge of computing 6,500,000 digits for the second time.
----------
**C**<sub>*MRB*</sub> is defined below. See http://mathworld.wolfram.com/MRBConstant.html.
I developed this informal catalog of formulas for the MRB constant with over 20 years of research and ideas from users like you.
**C**<sub>*MRB*</sub>=![enter image description here][7], based on
**C**<sub>*MRB*</sub>
![eta equals][8]
![enter image description here][9]
is proven below by an internet scholar going by the moniker "Dark Malthorp."
![Dark Marthorp's proof][10]
----------
----------
----------
![eta sums][11] denoting the kth derivative of the Dirichlet eta function of k and 0 respectively,
was first discovered in 2012 by Richard Crandall of Apple Computer.
The left half is proven below by Gottfried Helms and it is proven more rigorously![(][12]considering the conditionally convergent sum,![enter image description here][13]![)][14] below that. Then the right half is a Taylor expansion of ?(s) around s = 0.
> ![n^(1/n)-1][15]
At
[https://math.stackexchange.com/questions/1673886/is-there-a-more-rigorous-way-to-show-these-two-sums-are-exactly-equal][16],
it has been noted that "even though one has cause to be a little bit wary around formal rearrangements of conditionally convergent sums (see the [Riemann series theorem][17]), it's not very difficult to validate the formal manipulation of Helms. The idea is to cordon off a big chunk of the infinite double summation (all the terms from the second column on) that we know is absolutely convergent, which we are then free to rearrange with impunity. (Most relevantly for our purposes here, see pages 80-85 of this [document][18], culminating with the Fubini theorem which is essentially the manipulation Helms is using.)"
> ![argrument 1][19] ![argrument 2][20]
----------
----------
----------
We see many more integrals for **C**<sub>*MRB*</sub>.
We can expand
![1/x][21]
into the following.
![xx = 25.656654035][22]
xx = 25.65665403510586285599072933607445153794770546058072048626118194\
90097321718621288009944007124739159792146480733342667`100.;
g[x_] = x^(xx/
x); I NIntegrate[(g[(-t I + 1)] - g[(t I + 1)])/(Exp[Pi t] -
Exp[-Pi t]), {t, 0, Infinity}, WorkingPrecision -> 100]
(*
0.18785964246206712024851793405427323005590309490013878617200468408947\
72315646602137032966544331074969.*)
**Expanding upon the previously mentioned**
![enMRB sinh][23]
we get the following set of formulas that all equal **C**<sub>*MRB*</sub>:
Let
x= 25.656654035105862855990729 ...
along with the following constants (approximate values given)
{u = -3.20528124009334715662802858},
{u = -1.975955817063408761652299},
{u = -1.028853359952178482391753},
{u = 0.0233205964164237996087020},
{u = 1.0288510656792879404912390},
{u = 1.9759300365560440110320579},
{u = 3.3776887945654916860102506},
{u = 4.2186640662797203304551583} or
$
u = \infty .$
Another set follows.
let
x = 1 and
along with the following {approximations}
{u = 2.451894470180356539050514},
{u = 1.333754341654332447320456} or
$
u = \infty $
then
![enter image description here][24]
See
[this notebook from the wolfram cloud][25]
for justification.
----------
----------
Also, in terms of the Euler-Riemann zeta function,
**C**<sub>*MRB*</sub> =![enter image description here][26]
Furthermore, as ![enter image description here][27],
according to [user90369][28] at StackExchange, **C**<sub>*MRB*</sub> can be written as the sum of zeta derivatives similar to the eta derivatives discovered by Crandall.
![zeta hint ][29]Informations about ?<sup>(j)</sup>(k) please see e.g. [here][30], formulas (11)+(16)+(19).![credit][31]
In the light of the parts above, where
**C**<sub>*MRB*</sub>
= ![k^(1/k)-1][32]
= ![eta'(k)][33]
= ![sum from 0][34] ![enter image description here][35]
as well as ![double equals RHS][36]
an internet scholar going by the moniker "Dark Malthorp" wrote:
> ![eta *z^k][37]
----------
Here is proof of a faster converging integral for its integrated analog (The MKB constant) by Ariel Gershon.
g(x)=x^(1/x), M1=![hypothesis][38]
Which is the same as
![enter image description here][39]
because changing the upper limit to 2N + 1 increases MI by 2i/?.
MKB constant calculations have been moved to their own discussion at [http://community.wolfram.com/groups/-/m/t/1323951?p_p_auth=W3TxvEwH][40] .
![Iimofg->1][41]
![Cauchy's Integral Theorem][42]
![Lim surface h gamma r=0][43]
![Lim surface h beta r=0][44]
![limit to 2n-1][45]
![limit to 2n-][46]
Plugging in equations [5] and [6] into equation [2] gives us:
![left][47]![right][48]
Now take the limit as N?? and apply equations [3] and [4] :
![QED][49]
He went on to note that
![enter image description here][50]
I wondered about the relationship between CMRB and its integrated analog and asked the following.
![enter image description here][51]
So far I came up with
&[Wolfram Notebook][52]
Another relationship between the sum and integral that remains more unproven than I would like is
![CMRB(1-i)][53]
f[x_] = E^(I \[Pi] x) (1 - (1 + x)^(1/(1 + x)));
CMRB = NSum[f[n], {n, 0, Infinity}, WorkingPrecision -> 30,
Method -> "AlternatingSigns"];
M2 = NIntegrate[f[t], {t, 0, Infinity I}, WorkingPrecision -> 50];
part = NIntegrate[(Im[2 f[(-t)]] + (f[(-t)] - f[(t)]))/(-1 +
E^(-2 I \[Pi] t)), {t, 0, Infinity I}, WorkingPrecision -> 50];
CMRB (1 - I) - (M2 - part)
gives
> 6.103779*10^-23 - 6.103779*10^-23 I.
----------
----------
----------
As with any scientific paper, this post contains only reproducible results with methods. These records represent the advancement of consumer-level computers and clever programming over the past 20 years. I see others breaking these records, even after I die!
Here are some record computations. If you know of any others let me know.
- On or about Dec 31, 1998, I computed 1 digit of the (additive inverse of ) **C**<sub>*MRB*</sub> with my TI-92s, by adding 1-sqrt(2)+3^(1/3)-4^(1/4)+... as far as I could. That first digit, by the way, is just 0. Then by using the sum feature, in approximate mode, to compute $\sum _{n=1}^{1000 } (-1)^n \left(n^{1/n}\right),$
I computed the first correct decimal of $\text{CMRB}=\sum _{n=1}^{\infty } (-1)^n \left(n^{1/n}-1\right)$ i.e. (.1). It gave (.1_91323989714) which is close to what Mathematica gives for summing to only an upper limit of 1000.
- On Jan 11, 1999, I computed 4 decimals(.1878) of **C**<sub>*MRB*</sub> with the Inverse Symbolic Calculator, with the command evalf( 0.1879019633921476926565342538468+sum((-1)^n* (n^(1/n)-1),n=140001..150000)); where 0.1879019633921476926565342538468 was the running total of t=sum((-1)^n* (n^(1/n)-1),n=1..10000), then t= t+the sum from (10001.. 20000), then t=t+the sum from (20001..30000) ... up to t=t+the sum from (130001..140000).
- In Jan of 1999, I computed 5 correct decimals (rounded to .18786)of **C**<sub>*MRB*</sub> using Mathcad 3.1 on a 50 MHz 80486 IBM 486 personal computer operating on Windows 95.
- Shortly afterward I tried to compute 9 digits of **C**<sub>*MRB*</sub> using Mathcad 7 professional on the Pentium II mentioned below, by summing (-1)^x x^(1/x) for x=1 to 10,000,000, 20,000,000, and a many more, then linearly approximating the sum to a what a few billion terms would have given.
- On Jan 23, 1999, I computed 500 digits of **C**<sub>*MRB*</sub> with an online tool called Sigma. Remarkably the sum in 4. was correct to 6 of the 9 decimal places! See
[http://marvinrayburns.com/Original_MRB_Post.html][54]
if you can read the printed and scanned copy there.
- In September of 1999, I computed the first 5,000 digits of **C**<sub>*MRB*</sub> on a 350 MHz Pentium II with 64 Mb of RAM using the simple PARI commands \p 5000;sumalt(n=1,((-1)^n*(n^(1/n)-1))), after allocating enough memory.
- On June 10-11, 2003 over a period, of 10 hours, on a 450 MHz P3 with an available 512 MB RAM, I computed 6,995 accurate digits of **C**<sub>*MRB*</sub>.
- Using a Sony Vaio P4 2.66 GHz laptop computer with 960 MB of available RAM, at 2:04 PM 3/25/2004, I finished computing 8000 digits of **C**<sub>*MRB*</sub>.
- On March 01, 2006, with a 3 GHz PD with 2 GB RAM available, I computed the first 11,000 digits of **C**<sub>*MRB*</sub>.
- On Nov 24, 2006, I computed 40, 000 digits of **C**<sub>*MRB*</sub> in 33 hours and 26 min via my program written in Mathematica 5.2. The computation was run on a 32-bit Windows 3 GHz PD desktop computer using 3.25 GB of Ram.
The program was something like this:
Block[{a, b = -1, c = -1 - d, d = (3 + Sqrt[8])^n,
n = 131 Ceiling[40000/100], s = 0}, a[0] = 1;
d = (d + 1/d)/2; For[m = 1, m < n, a[m] = (1 + m)^(1/(1 + m)); m++];
For[k = 0, k < n, c = b - c;
b = b (k + n) (k - n)/((k + 1/2) (k + 1)); s = s + c*a[k]; k++];
N[1/2 - s/d, 40000]]
- Finishing on July 29, 2007, at 11:57 PM EST, I computed 60,000 digits of **C**<sub>*MRB*</sub>. Computed in 50.51 hours on a 2.6 GHz AMD Athlon with 64 bit Windows XP. Max memory used was 4.0 GB of RAM.
- Finishing on Aug 3, 2007, at 12:40 AM EST, I computed 65,000 digits of **C**<sub>*MRB*</sub>. Computed in only 50.50 hours on a 2.66 GHz Core 2 Duo using 64 bit Windows XP. Max memory used was 5.0 GB of RAM.
- Finishing on Aug 12, 2007, at 8:00 PM EST, I computed 100,000 digits of **C**<sub>*MRB*</sub>. They were computed in 170 hours on a 2.66 GHz Core 2 Duo using 64 bit Windows XP. Max memory used was 11.3 GB of RAM. The typical daily record of memory used was 8.5 GB of RAM.
- Finishing on Sep 23, 2007, at 11:00 AM EST, I computed 150,000 digits of **C**<sub>*MRB*</sub>. They were computed in 330 hours on a 2.66 GHz Core 2 Duo using 64 bit Windows XP. Max memory used was 22 GB of RAM. The typical daily record of memory used was 17 GB of RAM.
- Finishing on March 16, 2008, at 3:00 PM EST, I computed 200,000 digits of **C**<sub>*MRB*</sub> using Mathematica 5.2. They were computed in 845 hours on a 2.66 GHz Core 2 Duo using 64 bit Windows XP. Max memory used was 47 GB of RAM. The typical daily record of memory used was 28 GB of RAM.
- Washed away by Hurricane Ike -- on September 13, 2008 sometime between 2:00 PM - 8:00 PM EST an almost complete computation of 300,000 digits of **C**<sub>*MRB*</sub> was destroyed. Computed for a long 4015. Hours (23.899 weeks or 1.4454*10^7 seconds) on a 2.66 GHz Core 2 Duo using 64 bit Windows XP. Max memory used was 91 GB of RAM. The Mathematica 6.0 code used follows:
Block[{$MaxExtraPrecision = 300000 + 8, a, b = -1, c = -1 - d,
d = (3 + Sqrt[8])^n, n = 131 Ceiling[300000/100], s = 0}, a[0] = 1;
d = (d + 1/d)/2; For[m = 1, m < n, a[m] = (1 + m)^(1/(1 + m)); m++];
For[k = 0, k < n, c = b - c;
b = b (k + n) (k - n)/((k + 1/2) (k + 1)); s = s + c*a[k]; k++];
N[1/2 - s/d, 300000]]
- On September 18, 2008, computation of 225,000 digits of **C**<sub>*MRB*</sub> was started with a 2.66 GHz Core 2 Duo using 64 bit Windows XP. It was completed in 1072 hours. Memory usage is recorded in the attachment pt 225000.xls, near the bottom of this post.
- 250,000 digits were attempted but failed to be completed to a serious internal error that restarted the machine. The error occurred sometime on December 24, 2008, between 9:00 AM and 9:00 PM. The computation began on November 16, 2008, at 10:03 PM EST. Like the 300,000 digit computation, this one was almost complete when it failed. The Max memory used was 60.5 GB.
- On Jan 29, 2009, 1:26:19 pm (UTC-0500) EST, I finished computing 250,000 digits of **C**<sub>*MRB*</sub>. with a multiple-step Mathematica command running on a dedicated 64 bit XP using 4 GB DDR2 RAM onboard and 36 GB virtual. The computation took only 333.102 hours. The digits are at http://marvinrayburns.com/250KMRB.txt. The computation is completely documented in the attached 250000.PD at bottom of this post.
- On Sun 28 Mar 2010 21:44:50 (UTC-0500) EST, I started a computation of 300000 digits of **C**<sub>*MRB*</sub> using an i7 with 8.0 GB of DDR3 RAM onboard, but it failed due to hardware problems.
- I computed 299,998 Digits of **C**<sub>*MRB*</sub>. The computation began Fri 13 Aug 2010 10:16:20 pm EDT and ended 2.23199*10^6 seconds later |
Wednesday, September 8, 2010. I used Mathematica 6.0 for Microsoft
Windows (64-bit) (June 19, 2007) That is an average of 7.44 seconds per digit. I used my Dell Studio XPS 8100 i7 860 @ 2.80 GHz with 8GB physical DDR3 RAM. Windows 7 reserved an additional 48.929
GB virtual Ram.
- I computed exactly 300,000 digits to the right of the decimal point
of **C**<sub>*MRB*</sub> from Sat 8 Oct 2011 23:50:40 to Sat 5 Nov 2011
19:53:42 (2.405*10^6 seconds later). This run was 0.5766 seconds per digit slower than the
299,998 digit computation even though it used 16 GB physical DDR3 RAM on the same machine. The working precision and accuracy goal
combination were maximized for exactly 300,000 digits, and the result was automatically saved as a file instead of just being displayed on the front end. Windows reserved a total of 63 GB of working memory of which 52 GB were recorded being used. The 300,000 digits came from the Mathematica 7.0 command
Quit; DateString[]
digits = 300000; str = OpenWrite[]; SetOptions[str,
PageWidth -> 1000]; time = SessionTime[]; Write[str,
NSum[(-1)^n*(n^(1/n) - 1), {n, \[Infinity]},
WorkingPrecision -> digits + 3, AccuracyGoal -> digits,
Method -> "AlternatingSigns"]]; timeused =
SessionTime[] - time; here = Close[str]
DateString[]
- 314159 digits of the constant took 3 tries due to hardware failure. Finishing on September 18, 2012, I computed 314159 digits, taking 59 GB of RAM. The digits came from the Mathematica 8.0.4 code
DateString[]
NSum[(-1)^n*(n^(1/n) - 1), {n, \[Infinity]},
WorkingPrecision -> 314169, Method -> "AlternatingSigns"] // Timing
DateString[]
- Sam Noble of Apple computed 1,000,000 digits of **C**<sub>*MRB*</sub> in 18 days 9 hours 11 minutes 34.253417 seconds.
- Finishing on Dec 11, 2012, Richard Crandall, an Apple scientist, computed 1,048,576 digits
in a lightning-fast 76.4 hours computation time (from the timing command). That's on a 2.93 GHz 8-core Nehalem.
- In Aug of 2018, I computed 1,004,993 digits of **C**<sub>*MRB*</sub> in 53.5 hours with 10 DDR4 RAM (of up to 3000 MHz) supported processor cores overclocked up to 4.7 GHz! Search this post for "53.5" for documentation.
- Sept 21, 2018: I computed 1,004,993 digits of **C**<sub>*MRB*</sub>
in 50.37 hours of absolute time (35.4 hours computation time) with 18
(DDR3 and DDR4) processor cores! Search this post for "50.37 hours"
for documentation.**
- On May 11, 2019, I computed over 1,004,993 digits, using 28 kernels
on 18 DDR4 RAM (of up to 3200 MHz) supported cores overclocked up to
5.1 GHz in 45,5 hours of absolute time and only 32.5 hours of computation time! Search 'Documented in the attached ":3 fastest
computers together 3.nb." ' for the post that has the attached documenting notebook.
- On 10/19/20, using 3/4 of the MRB constant supercomputer 2, I finished an over 1,004,993 digits computation of **C**<sub>*MRB*</sub> in 44 hours of absolute time -- see [https://www.wolframcloud.com/obj/bmmmburns/Published/44%20hour%20million.nb][55] for documentation.
- I computed a little over 1,200,000 digits of **C**<sub>*MRB*</sub> in 11
days, 21 hours, 17 minutes, and 41 seconds (finishing on March 31, 2013). I used a six-core Intel(R) Core(TM) i7-3930K CPU @ 3.20 GHz 3.20 GHz.
- On May 17, 2013, I finished a 2,000,000 or more digit computation of **C**<sub>*MRB*</sub>, using only around 10GB of RAM. It took 37 days 5 hours 6 minutes 47.1870579 seconds. I used my six-core Intel(R) Core(TM) i7-3930K CPU @ 3.20 GHz 3.20 GHz.
- A previous world record computation of **C**<sub>*MRB*</sub> was finished on Sun 21 Sep 2014 at 18:35:06. It took 1 month 27 days 2 hours 45 minutes 15 seconds. The processor time from the 3,000,000+ digit computation was 22 days. I computed the 3,014,991 digits of **C**<sub>*MRB*</sub> with Mathematica 10.0. I Used my new version of Richard Crandall's code in the attached 3M.nb, optimized for my platform and large computations. I also used a six-core Intel(R) Core(TM) i7-3930K CPU @ 3.20 GHz with 64 GB of RAM of which only 16 GB was used. Can you beat it (in more number of digits, less memory used, or less time taken)? This confirms that my previous "2,000,000 or more digit computation" was accurate to 2,009,993 digits. they were used to check the first several digits of this computation. See attached 3M.nb for the full code and digits.
- Finished on Wed 16 Jan 2019 19:55:20, I computed over 4 million digits of **C**<sub>*MRB*</sub>.
It took 4 years of continuous tries. This successful run took 65.13 days computation time, with a processor time of 25.17 days, on a 3.7 GHz overclocked up to 4.7 GHz on all cores Intel 6 core computer with 3000 MHz RAM. According to this computation, the previous record, 3,000,000+ digit computation, was accurate to 3,014,871 decimals, as this computation used my algorithm for computing n^(1/n) as found in chapter 3 in the paper at
https://www.sciencedirect.com/science/article/pii/0898122189900242
and the 3 million+ computation used Crandall's algorithm. Both algorithms outperform Newton's method per calculation and iteration.
See attached [notebook][56].
M R Burns' algorithm:
x = SetPrecision[x, pr];
y = x^n; z = (n - y)/y;
t = 2 n - 1; t2 = t^2;
x =
x*(1 + SetPrecision[4.5, pr] (n - 1)/t2 + (n + 1) z/(2 n t) -
SetPrecision[13.5, pr] n (n - 1) 1/(3 n t2 + t^3 z));
(*N[Exp[Log[n]/n],pr]*)
Example:
ClearSystemCache[]; n = 123456789;
(*n is the n in n^(1/n)*)
x = N[n^(1/n),100];
(*x starts out as a relatively small precision approximation to n^(1/n)*)
pc = Precision[x]; pr = 10000000;
(*pr is the desired precision of your n^(1/n)*)
Print[t0 = Timing[While[pc < pr, pc = Min[4 pc, pr];
x = SetPrecision[x, pc];
y = x^n; z = (n - y)/y;
t = 2 n - 1; t2 = t^2;
x = x*(1 + SetPrecision[4.5, pc] (n - 1)/t2 + (n + 1) z/(2 n t)
- SetPrecision[13.5, pc] n (n - 1)/(3 n t2 + t^3 z))];
(*You get a much faster version of N[n^(1/n),pr]*)
N[n - x^n, 10]](*The error*)];
ClearSystemCache[]; n = 123456789; Print[t1 = Timing[N[n - N[n^(1/n), pr]^n, 10]]]
Gives
{25.5469,0.*10^-9999984}
{101.359,0.*10^-9999984}
R Crandall's algorithm:
While[pc < pr, pc = Min[3 pc, pr];
x = SetPrecision[x, pc];
y = x^n - n;
x = x (1 - 2 y/((n + 1) y + 2 n n));];
(*N[Exp[Log[n]/ n],pr]*)
Example:
ClearSystemCache[]; n = 123456789;
(*n is the n in n^(1/n)*)
x = N[n^(1/n)];
(*x starts out as a machine precision approximation to n^(1/n)*)
pc = Precision[x]; pr = 10000000;
(*pr is the desired precision of your n^(1/n)*)
Print[t0 = Timing[While[pc < pr, pc = Min[3 pc, pr];
x = SetPrecision[x, pc];
y = x^n - n;
x = x (1 - 2 y/((n + 1) y + 2 n n));];
(*N[Exp[Log[n]/n],pr]*)
N[n - x^n, 10]](* The error*)]; Print[
t1 = Timing[N[n - N[n^(1/n), pr]^n, 10]]]
Gives
{32.1406,0.*10^-9999984}
{104.516,0.*10^-9999984}
More information available upon request.
----------
- Finished on Fri 19 Jul 2019 18:49:02, I computed over 5 million digits of **C**<sub>*MRB*</sub>.
Methods described in the reply below that starts with "Attempts at a 5,000,000 digit calculation ."
For this 5 million calculation of MRB using the 3 node MRB supercomputer:
processor time was 40 days.
and the actual time was 64 days.
That is faster than the 4 million digit computation using just one node.
- I finally computed 6,000,000 digits of the MRB constant after 8 tries in 19 months. (Search "8/24/2019 It's time for more digits!" below.) finishing on Tue 30 Mar 2021 22:02:49 in 160 days.
The MRB constant supercomputer 2 said the following:
Finished on Tue 30 Mar 2021 22:02:49. Processor and actual time were 5.28815859375*10^6 and 1.38935720536301*10^7 s. respectively
Enter MRB1 to print 6029991 digits. The error from a 5,000,000 or more digit calculation that used a different method is
0.*10^-5024993
That means that the 5,000,000 digit computation Was actually accurate to 5024993 decimals!!!
----------
----------
----------
----------
Here is my mini-cluster of the fastest 3 computers (the MRB constant supercomputer 0) mentioned below:
The one to the left is my custom-built extreme edition 6 core and later with an 8 core Xeon processor.
The one in the center is my fast little 4 core Asus with 2400 MHz RAM.
Then the one on the right is my fastest -- a Digital Storm 6 core overclocked to 4.7 GHz on all cores and with 3000 MHz RAM.
![first 3 way cluster][57]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=1ac.JPG&userId=366611
[2]: https://community.wolfram.com//c/portal/getImageAttachment?filename=10878Capture.JPG&userId=366611
[3]: https://www.wolframcloud.com/obj/bmmmburns/Published/Sept_5_2021.nb
[4]: https://community.wolfram.com//c/portal/getImageAttachment?filename=8785Capture1.JPG&userId=366611
[5]: https://community.wolfram.com//c/portal/getImageAttachment?filename=10043Capture2.JPG&userId=366611
[6]: https://community.wolfram.com//c/portal/getImageAttachment?filename=75504.JPG&userId=366611
[7]: https://community.wolfram.com//c/portal/getImageAttachment?filename=1593Capture1.JPG&userId=366611
[8]: https://community.wolfram.com//c/portal/getImageAttachment?filename=5191Capture3.JPG&userId=366611
[9]: https://community.wolfram.com//c/portal/getImageAttachment?filename=47625a.JPG&userId=366611
[10]: https://community.wolfram.com//c/portal/getImageAttachment?filename=6657Capture12.JPG&userId=366611
[11]: https://community.wolfram.com//c/portal/getImageAttachment?filename=2081Capture14.JPG&userId=366611
[12]: https://community.wolfram.com//c/portal/getImageAttachment?filename=left.gif&userId=366611
[13]: https://community.wolfram.com//c/portal/getImageAttachment?filename=3959Capture7.JPG&userId=366611
[14]: https://community.wolfram.com//c/portal/getImageAttachment?filename=right.gif&userId=366611
[15]: https://community.wolfram.com//c/portal/getImageAttachment?filename=10297Capture.JPG&userId=366611
[16]: https://math.stackexchange.com/questions/1673886/is-there-a-more-rigorous-way-to-show-these-two-sums-are-exactly-equal
[17]: https://en.wikipedia.org/wiki/Riemann_series_theorem
[18]: https://www.math.ucdavis.edu/~hunter/intro_analysis_pdf/ch4.pdf
[19]: https://community.wolfram.com//c/portal/getImageAttachment?filename=7211Capture.JPG&userId=366611
[20]: https://community.wolfram.com//c/portal/getImageAttachment?filename=10837Capture.JPG&userId=366611
[21]: https://community.wolfram.com//c/portal/getImageAttachment?filename=Capture21%281%29.JPG&userId=366611
[22]: https://community.wolfram.com//c/portal/getImageAttachment?filename=9644Capture.JPG&userId=366611
[23]: https://community.wolfram.com//c/portal/getImageAttachment?filename=Capture23.JPG&userId=366611
[24]: https://community.wolfram.com//c/portal/getImageAttachment?filename=115335.JPG&userId=366611
[25]: https://www.wolframcloud.com/obj/bmmmburns/Published/double%20zeroes%20of%20CMRB.nb
[26]: https://community.wolfram.com//c/portal/getImageAttachment?filename=11i.JPG&userId=366611
[27]: https://community.wolfram.com//c/portal/getImageAttachment?filename=6033d.JPG&userId=366611
[28]: https://math.stackexchange.com/users/332823/user90369
[29]: https://community.wolfram.com//c/portal/getImageAttachment?filename=1558a.JPG&userId=366611
[30]: https://digitalcommons.wku.edu/cgi/viewcontent.cgi?referer=http://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=27&ved=2ahUKEwjMx5SuxbnjAhVLLpoKHcBPBWo4FBAWMAZ6BAgAEAI&url=http://digitalcommons.wku.edu/cgi/viewcontent.cgi?article=2093&context=theses&usg=AOvVaw0gQx0dl_Nw4esC2IQc0LEo&httpsredir=1&article=2093&context=theses
[31]: https://community.wolfram.com//c/portal/getImageAttachment?filename=2965b.JPG&userId=366611
[32]: https://community.wolfram.com//c/portal/getImageAttachment?filename=11ka.JPG&userId=366611
[33]: https://community.wolfram.com//c/portal/getImageAttachment?filename=84481.JPG&userId=366611
[34]: https://community.wolfram.com//c/portal/getImageAttachment?filename=1869Capture.JPG&userId=366611
[35]: https://community.wolfram.com//c/portal/getImageAttachment?filename=6878p1o2.jpg&userId=366611
[36]: https://community.wolfram.com//c/portal/getImageAttachment?filename=5630Capture2.JPG&userId=366611
[37]: https://community.wolfram.com//c/portal/getImageAttachment?filename=11k.JPG&userId=366611
[38]: https://community.wolfram.com//c/portal/getImageAttachment?filename=46311.PNG&userId=366611
[39]: https://community.wolfram.com//c/portal/getImageAttachment?filename=580910.JPG&userId=366611
[40]: http://community.wolfram.com/groups/-/m/t/1323951?p_p_auth=W3TxvEwH
[41]: https://community.wolfram.com//c/portal/getImageAttachment?filename=28491.JPG&userId=366611
[42]: https://community.wolfram.com//c/portal/getImageAttachment?filename=76812.JPG&userId=366611
[43]: https://community.wolfram.com//c/portal/getImageAttachment?filename=100173.JPG&userId=366611
[44]: https://community.wolfram.com//c/portal/getImageAttachment?filename=57664.JPG&userId=366611
[45]: https://community.wolfram.com//c/portal/getImageAttachment?filename=74665.JPG&userId=366611
[46]: https://community.wolfram.com//c/portal/getImageAttachment?filename=49236.JPG&userId=366611
[47]: https://community.wolfram.com//c/portal/getImageAttachment?filename=15127.JPG&userId=366611
[48]: https://community.wolfram.com//c/portal/getImageAttachment?filename=92858.JPG&userId=366611
[49]: https://community.wolfram.com//c/portal/getImageAttachment?filename=49309.JPG&userId=366611
[50]: https://community.wolfram.com//c/portal/getImageAttachment?filename=3.PNG&userId=366611
[51]: https://community.wolfram.com//c/portal/getImageAttachment?filename=1021422.JPG&userId=366611
[52]: https://www.wolframcloud.com/obj/b72d7291-a801-496f-977a-34dfd55350c2
[53]: https://community.wolfram.com//c/portal/getImageAttachment?filename=8a.JPG&userId=366611
[54]: http://marvinrayburns.com/Original_MRB_Post.html
[55]: https://www.wolframcloud.com/obj/bmmmburns/Published/44%20hour%20million.nb
[56]: https://community.wolfram.com/groups?p_auth=zWk1Qjoj&p_p_auth=r1gPncLu&p_p_id=19&p_p_lifecycle=1&p_p_state=exclusive&p_p_mode=view&p_p_col_id=column-1&p_p_col_count=6&_19_struts_action=/message_boards/get_message_attachment&_19_messageId=1593151&_19_attachment=4%20million%2011%202018.nb
[57]: http://community.wolfram.com//c/portal/getImageAttachment?filename=ezgif.com-video-to-gif.gif&userId=366611Marvin Ray Burns2014-10-09T18:08:49ZIntersection points of two planes?
https://community.wolfram.com/groups/-/m/t/2365163
I am trying to get intersecting points of the two planes. How can I obtain it?
![enter image description here][1]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=11.PNG&userId=2269999Kyaw Hla Chak2021-09-12T03:22:05ZError solving polynomial equation using Solve[ ]?
https://community.wolfram.com/groups/-/m/t/2363066
I have got two complex equations after some derivation with log and polynomial. But Solve and NSolve function cannot able to solve them stating "Solve was unable to solve the system with inexact coefficients or the system obtained by direct rationalization of inexact numbers present in the system. Since many of the methods used by Solve require exact input, providing Solve with an exact version of the system may help." Can anyone make any suggestions how can I solve that?
Attached the mathematica file.
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/e6a786eb-2e7d-49f3-ae3d-e23ea82daf24Kyaw Hla Chak2021-09-09T19:07:49ZWhere does the ResourceFunction stored locally?
https://community.wolfram.com/groups/-/m/t/2364831
Whenever we pull a function from the **Wolfram Function Repository** using "*ResourceFunction*", where does the downloaded files stored in the system?
![Using **ResourceFunction** to compute a **Collatz sequence** using the **Collatz** function.][1]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=Snip.png&userId=2364718Ajit Kumar Sahoo2021-09-11T05:33:44ZReplacing DeleteMissing while maintaining columns in Grid?
https://community.wolfram.com/groups/-/m/t/2364791
List
llc = {Entity["Company", "Moderna::6dvsm"],
Entity["Company", "NVIDIACorporation::7ymsk"],
Entity["Company", "Square::xx7qd"],
Entity["Company", "TeslaMotors::tpbn5"],
Entity["Company", "UpstartHoldings::g9csn"],
Entity["Company", "ZoomVideoCommunications::3y89f"],
Entity["Company", "Zscaler::9vw54"]} ;
Data from CompanyDate which has a lot of missing information
cdata = CompanyData[
llc, {"Name" , "CurrentRatio" , "Employees" ,
"FinancialHealthGrade", "ProfitabilityGrade" , "RevenueGrowth" ,
"NetIncomeGrowth" , "OperatingIncomeGrowth"}]
Deletion of missing information and results -- output does not display well so posted picture instead
In[222]:= cdata1 = Grid[DeleteMissing[cdata , All ], Frame -> All]
![enter image description here][1]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=4091Capture.PNG&userId=159426
Because of the deleted missing information, data jumps columns. How can I maintain column integrity??Raymond Low2021-09-11T05:18:39ZSelecting numbers with a specified leading digit?
https://community.wolfram.com/groups/-/m/t/2364859
I have a list like this:-
![The list][1]
Here numbers with the leading digit 1 are 10, 16, and 1. How can I compute this result in Mathematica?
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=New.png&userId=2364718Ajit Kumar Sahoo2021-09-11T08:31:29ZAfter using manipulate every manipulate computes the same graph
https://community.wolfram.com/groups/-/m/t/2364701
Hi there, anyone...
I used an example of manipulate with parametric plot, the initial graph I could alter making changes to the value of x, but now any value of x shows the same graph, including the initial example that gave me only a circle, now the initial example shows the graph that I modified...every manipulate with different values now gives me the same graph...what is happening? I used clearall and it remains the same...I am not being able to clear the memory to renew the graph even to its first graph example:
Manipulate[
ParametricPlot[{r Cos[x], r Sin[x]}, {x, 1, m}, {r, 0, k},
Mesh -> Full, PlotRange -> {{-2, 2}, {-2, 2}}], {m, 0, 20 Pi}, {k, 1,
3}]Luis Felipe Massena Misiec2021-09-10T16:16:58ZAnimation support in Wolfram Cloud?
https://community.wolfram.com/groups/-/m/t/2363170
I'm wondering if there are plans to support displaying animated gifs in Wolfram Cloud.
Without animations, I can't publish [this essay](https://machine-learning-etc.ghost.io/p/765acb0d-0985-4f91-8db5-d9457f11425f/) in notebook format.
Manipulate isn't the right fit for this because a high quality animation could take minutes or hours to render. For instance, animations in post above [used](https://mathematica.stackexchange.com/a/251452/217) `"3DRenderingMethod" -> "BSPTree"`, which is too slow for interactive use.
One way to address this is to allow embedding animated gifs into notebooks, and then let the browser display them. There are other lossless animation formats, but they don't have universal support like gifs.Yaroslav Bulatov2021-09-09T14:08:55ZFinding the first digits of 2^2^2^2^2^2
https://community.wolfram.com/groups/-/m/t/2359839
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/34c78076-8e13-471b-b527-cd6b87932374James Choi2021-09-04T11:55:11ZSyntax error while pasting a code
https://community.wolfram.com/groups/-/m/t/2362885
Exercise 5—Increasing and Decreasing Function (https://www.wolfram.com/wolfram-u/introduction-to-calculus/functions.html) include this code:
![enter image description here][1]
Not sure how to write it correctly. I copied and pasted on a notebook, but showing syntax error. ![enter image description here][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=Lesson2-io_12-i.en.png&userId=2211846
[2]: https://community.wolfram.com//c/portal/getImageAttachment?filename=Capture.JPG&userId=2211846Rajeev Bagra2021-09-09T09:36:51ZZ-Matrix template-based substitution for enumeration of 3D molecules
https://community.wolfram.com/groups/-/m/t/2364528
*SUPPLEMENTARY WOLFRAM MATERIALS for the ARTICLE:*
>Lorpaiboon, W. and Limpanuparb, T. (2021).
> Z-matrix template-based substitution approach for enumeration of 3D molecular structures.
> MethodsX, 8. [doi: 10.1016/j.mex.2021.101416][1]
> [Full article PDF][2]
&[Wolfram Notebook][3]
[1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8374508/
[2]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8374508/pdf/main.pdf
[3]: https://www.wolframcloud.com/obj/546fd82b-8fa2-4f1b-81a6-cdba300f26af
[Original notebook]: https://www.wolframcloud.com/obj/84d89123-5533-4847-b3f7-ef3cf120a79ePiyathida Tawornparcha2021-09-10T15:35:36ZUse Manipulate in a ParametricPlot ?
https://community.wolfram.com/groups/-/m/t/896287
Hi, I'm trying to manipulate a Parametric Plot, but I clearly see its not working because I'm not able to fix it, that's why I would love some help.
Regards
Manipulate[ParametricPlot[{r Cos[x], r Sin[y]}, {y,1,k}, {x, 0, n}, Mesh -> Full], {n, 0, 2 Pi}, {k, 1, 2}]Muhammad Afzal2016-07-30T07:33:09ZPlotting of circle involute
https://community.wolfram.com/groups/-/m/t/2342615
![enter image description here][1]
&[Wolfram Notebook][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=involute.gif&userId=20103
[2]: https://www.wolframcloud.com/obj/7f45381a-b143-45f4-b647-c0ff378df37eSandor Kabai2021-08-15T12:27:47Z