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RSS Feed for Wolfram Community showing any discussions in tag sorted by activeGödel overlooked this?
https://community.wolfram.com/groups/-/m/t/3149184
Hi friends!
I have written a book refuting Gödel, so far no one has been able to counter my argument.
Basically, he took an x not belonging to himself. However, there is nothing that does not belong to itself; he should have at least demonstrated the existence of such an x to start taking the first step towards his proof. I send you chapter 4 for appreciation.
Salaam
[To buy my book][1]
[1]: https://www.amazon.com/dp/B0CS8SX7KWLeonardo Correia Mota2024-03-29T09:39:37ZEnsure Your Success: Ace the AZ-305 Certification with Pass4Success
https://community.wolfram.com/groups/-/m/t/3149329
The Microsoft AZ-305 test, part of the Azure results Architect Expert testing system, tests organizing skills in designing and enforcing Azure results. Covering areas like governance, security, storehouse, computing, and networking, passing this test validates your skill in architecting results on Azure, boosting career openings in computing and IT. Passing the AZ- 305 test through Pass4Success enhances your career prospects and showcases your dedication to excellence in AZ- 305 issues. Pass4Success offers ultra-expensive test medication products specially designed for the AZ- 305 test, including Questions and Answers reflecting the factual test content. Our commitment to providing exceptional training includes Practice Test software available in Desktop and web-grounded performances and PDF format for easy access across multiple orientations.
Explore our Free Demo: https://www.pass4success.com/microsoft/exam/az-305luna watson2024-03-29T06:42:35ZHow to set proxies for the browser started by StartWebSession?
https://community.wolfram.com/groups/-/m/t/2617324
I try to set the proxy as follows, but failed:
In[209]:= (*
https://mathematica.stackexchange.com/questions/242495/chrome-driver-error-in-startwebsession
$DefaultProxyRules
*)
(*Set a proxy specification for the HTTP protocol:*)
origUseProxy=$DefaultProxyRules["UseProxy"];
origHttpProxy=$DefaultProxyRules["HTTP"];
origHttpsProxy=$DefaultProxyRules["HTTPS"];
origSocksProxy=$DefaultProxyRules["Socks"];
$DefaultProxyRules["HTTP"] = {"127.0.0.1", 8080};
$DefaultProxyRules["HTTPS"] = {"127.0.0.1", 8080};
$DefaultProxyRules["Socks"] = {"127.0.0.1", 18889};
(*Because the "UseProxy" value acts like a master switch, that HTTP proxy specification will not take effect unless "UseProxy" is set to Manual:*)
$DefaultProxyRules["UseProxy"] = Manual;
In[224]:= (*Use Visible->False to run the browser in "\[AliasDelimiter]ess" mode, where the browser window does not actually become visible:*)
(*session = StartWebSession["Chrome", Visible -> False];*)
session = StartWebSession[]
page = WebExecute[
"OpenPage" ->
"https://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-getgen?list=new&what=gen&gnum=227"];
inputs = WebExecute[session, "LocateElements" -> "Tag" -> "Input"];
WebExecute[session, "ClickElement" -> Last@inputs];
anchors = WebExecute["LocateElements" -> "Tag" -> "a"];
Select[WebExecute["PageHyperlinks"], StringContainsQ["gnum="]]
DeleteObject[session];
Out[224]= Failure["StartWebSession", <|"MessageTemplate" -> "Unable \
to start `driver` driver process",
"MessageParameters" -> <|"driver" -> "Chrome"|>|>]
During evaluation of In[224]:= URLRead::invhttp: Empty reply from server.
During evaluation of In[224]:= WebExecute::argr: The arguments for WebExecute are not valid.
During evaluation of In[224]:= Last::normal: Nonatomic expression expected at position 1 in Last[$Failed].
During evaluation of In[224]:= WebExecute::argr: The arguments for WebExecute are not valid.
During evaluation of In[224]:= URLRead::invhttp: Empty reply from server.
During evaluation of In[224]:= URLRead::invhttp: Empty reply from server.
During evaluation of In[224]:= StringContainsQ::strse: String or list of strings expected at position 1 in StringContainsQ[gnum=][<|MessageTemplate->`command` failed.,MessageParameters-><|command->PageHyperlinks|>|>].
Out[229]= Failure[]
During evaluation of In[224]:= DeleteObject::nim: Cannot delete object Failure[\[WarningSign] Message: Unable to start Chrome driver process
Tag: StartWebSession
].
Any hints for fixing this problem?
P.S. This question is initially posted [here](https://community.wolfram.com/groups/-/m/t/2617178). But according to Daniel Lichtblau's suggestion, it is appropriate to start a new discussion.
Regards,
ZhaoHongyi Zhao2022-09-16T00:03:01ZEfficiency of road networks
https://community.wolfram.com/groups/-/m/t/3149145
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/a212bddc-f448-49fe-8afa-525040bc04ecChristopher Wolfram2024-03-29T02:27:26ZConnectivity constraints on the rule (Wolfram Stephen graphs)
https://community.wolfram.com/groups/-/m/t/3085408
Hi, I am analyzing chapter 3.2 in the book "A Class of Models with the Potential to Represent Fundamental Physics" by Wolfram Stephen and I am having trouble understanding **left connectivity constraint on rule**. I would be grateful if someone could show this by example of some rule.
Dominik.Dominik Krząstek2023-12-16T11:57:11ZCooling by a cylindrical pin fin
https://community.wolfram.com/groups/-/m/t/3146557
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/452fad01-0da6-461a-bae8-468ffd6d6ecaHousam Binous2024-03-24T09:55:06Z[WSG24] Daily Study Group: Wolfram Tools for LLMs
https://community.wolfram.com/groups/-/m/t/3137427
A Wolfram U Daily Study Group focusing on **LLMs and Wolfram Tech** will be starting soon!
Join Wolfram Experts [@Alan Joyce][at0] , [Rick Hennigan][1], [Timothee Verdier][2] and [@Jon McLoone][at1] and a group of fellow enthusiasts to learn about all the different ways you can use Wolfram tech along with Large Language Models (LLMs). Our topics for the study group include the Wolfram GPT, Chat Notebooks and LLM Functionality in Wolfram Language. The sessions will feature a number of fun examples that will show you how you can combine the computational powers and curated knowledge of Wolfram Language along with the generative capabilities of LLMs.
Each session will kick off with a presentation by an expert who will introduce the topic, followed by some review questions and discussions. There will be time for Q&A at the end.
No prior Wolfram Language experience is required to join the study group.
Please feel free to use this thread to collaborate and share ideas, materials and links to other resources with fellow learners.
We look forward to seeing you:
March 25th-29th, 2024,
11am-12pm CT (4-5pm GMT)
> **[REGISTER HERE][3]**
![enter image description here][4]
[at0]: https://community.wolfram.com/web/alanj
[at1]: https://community.wolfram.com/web/jonm
[1]: https://github.com/rhennigan
[2]: https://www.youtube.com/watch?v=oXwPX5aFV98
[3]: https://www.bigmarker.com/series/wsg50-wolfram-tools-for-llms/series_details?utm_bmcr_source=community
[4]: https://community.wolfram.com//c/portal/getImageAttachment?filename=WolframUBanner.jpeg&userId=130003Abrita Chakravarty2024-03-08T00:44:26ZMatrix with a very small determinant problem
https://community.wolfram.com/groups/-/m/t/3148782
Hi hope you are all doing well, I have the following matrix wish have a very small determinant wish makes a problem for me when I want to inverse it so before inversion, a preconditioning step is applied. This step involves finding the largest value (the pivot) in each row i located in a column j of rank higher than that of this row. The column containing the pivot and the column of rank equal to that of the row are then swapped. But I don't know how to do this preconditioning, If any of you have any idea it will help me a lot, Thank you all in advance.
Best regards Leo (Beginner at mathematica)
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/23a6de55-7d40-4d8b-ae5d-ec7c4df71c01Leo Murphy2024-03-28T14:19:25ZMathematica 13.3.1 installed on Raspberry Pi 5 does not support interaction with BasicMathAssistant
https://community.wolfram.com/groups/-/m/t/3147950
My new Raspberry Pi 5 runs the latest version of Raspberry OS (64-bit with the full set of applications) created by Raspberry Pi imager 1.8.5. Mathematica 13.3.1 is ialso nstalledll. It works properly with symbolically taped functions and operators but does not insert symbols clicked on panels of BasicMathAssistent into the notebook window.
What is the matter?
PS. There is no such problem with the same version of Mathematica installed on my Raspberry Pi 4 with previous version of 64-bit OS.Vladimir Rok2024-03-26T15:34:57ZHow can I skip the "middle" optional arguments in a function call?
https://community.wolfram.com/groups/-/m/t/3147849
Say I have a function with one mandatory and two optional arguments,
f[x_, y_ : 1, z_ : 2] := x^2 + y*z
Then how can I make a function call which gives values to both `x` and `z`, but not to `y`, such that `y` takes its default value. In Python I could call `f[2, z=1]` for example. What is the equivalent in Mathematica?Gernot H2024-03-26T13:09:32ZGenerating lists where new elements depend on the previous element
https://community.wolfram.com/groups/-/m/t/3148486
Hi all, I am interested in using some type of list or table in-built Mathematica function to generate a list, where the elements of the new list not only depends on the input values of a previously defined list of triplets which I denote as 'a', but also depends on the output value of the previous element of the new list. In this sense I will provide the list of triplets, the function f which takes the triplets as inputs, and the first element of the new list. Then the list should generate itself.
I provide a simple example, not the actual problem, where I use the % symbol in Mathematica to assign the previous cell output to the next iteration. But of course this is not efficient for long triplet lists. Can anyone advise on a more efficient way of doing this type of problem? Many thanks.
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/6011b109-d44f-4aaf-8a40-e7f4a50283dcByron Alexander2024-03-28T06:27:19ZUsing implicit Euler and fixed step size for solving
https://community.wolfram.com/groups/-/m/t/3146964
I used implicit Euler and fixed step size to solve the differential equation, but the system prompted that "FixedStep" cannot be used. What is the reason for this and how should I modify the program?
system = {vi q[t] == l il'[t] + ir[t] r, il[t] == ir[t], il[0] == 0};
control = {q[0] == 1,
WhenEvent[Mod[t, \[Tau]] == (2/3) \[Tau], q[t] -> 0],
WhenEvent[Mod[t, \[Tau]] == 0, q[t] -> 1]};
pars = {vi -> 24, r -> 22, l -> 2 10^-2,
c -> 1 10^-4, \[Tau] -> 25/10 10^-4};
sol = NDSolve[{system, control} /. pars, {il, q}, {t, 0, .2},
StartingStepSize -> step,
Method -> {"FixedStep", Method -> "LinearlyImplicitEuler"},
DiscreteVariables -> q];
a = Evaluate[il[t] /. sol];
Plot[a, {t, 0, 0.06}, AxesLabel -> {"s", "il[t]/A"},
PlotLegends -> {"LinearlyImplicitEuler"}, PlotStyle -> {Red},
PlotRange -> All]James James2024-03-25T05:43:21ZIntroduction to Stochastic Processes for Finance Research and Trading
https://community.wolfram.com/groups/-/m/t/3125647
This is the dedicated discussion of Wolfram U's course: Introduction to Stochastic Processes for Finance Research and Trading.
> **Take the course here:** https://www.wolfram.com/wolfram-u/courses/finance/stochastic-processes-finance-research-trading/
Please feel free to use this thread to collaborate and share ideas, materials and links to other resources with fellow learners as you work through the Introduction to Stochastic Processes for Finance Research and Trading course! Join Jonathan Kinlay and fellow learners to learn about modeling financial data with stochastic processes for quantitative research and trading. Course topics include properties and applications for various stochastic processes such as a random walk, the Wiener process and geometric Brownian motion. Analysts and portfolio managers in the financial sector often rely on computational models for managing assets and optimizing investment portfolios, and modeling stochastic processes helps you make sense of and predict outcomes in random data, like stock prices.
If you want more, try out Modeling Market Prices Using Stochastic Processes, Random Processes in Finance and Optimization of Portfolios and Investments on Wolfram U!
![enter image description here][1]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=WolframUBanner.png&userId=773999Jonathan Kinlay2024-02-21T09:32:02ZVisualizing total solar eclipses of one Saros series
https://community.wolfram.com/groups/-/m/t/3120094
[![enter image description here][1]][1]
&[Wolfram Notebook][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=sdf45gdafv.jpg&userId=11733
[2]: https://www.wolframcloud.com/obj/7e311381-646a-4284-a5d9-45924498fd2eJari Kirma2024-02-10T13:02:52ZThe AskConstants application for constant recognition
https://community.wolfram.com/groups/-/m/t/3148139
[![enter image description here][1] ][2]
*Figure 1: An exact result for an integral that Mathematica through 12.1 cannot do. (Click the image for higher resolution version)*
&[Wolfram Notebook][3]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=Maininterface2_callout.png&userId=20103
[2]: https://www.wolframcloud.com/obj/640da236-c104-458a-9a83-a1cf47a0b4c2
[3]: https://www.wolframcloud.com/obj/24702568-f3f8-4570-85af-b541b62272e9David Stoutemyer2024-03-26T19:53:11ZNDSolve error inside Plot: $RecursionLimit :Recursion depth of 1024 exceeded
https://community.wolfram.com/groups/-/m/t/3148528
hello, i have been trying to plot the maximum range for theta for a projectile motion experiencing linear drag, but i keep getting errors regarding the written code. when trying to transform y[t] to a function yy[t_] rather than the replacement rule there seems to be no wolfram language translation found and when rooting i get a message:$RecursionLimit
:Recursiondepthof1024exceeded.
tfinal[theta_]:=[s=NdSolve[{x' ' [t] == b x' [t] , y' ' [t] == -b y' [t] - g, x[0] == 0, y[0] == 0, x'[0] == v Cos [theta], y'[0] == v Sin[theta]}, {x,y}, {t, 0, 10}];
yy[t_] := y[t] /. s[[1]];
xx[t_] := x[t] /. s[[1]];
xfinal[theta_]:=x[tfinal[theta]]
plot[xfinal[theta], {theta,0.01,2.5}jony will2024-03-27T10:34:33ZAPI access to Claude 3 and use cases: image processing, conversation and programming
https://community.wolfram.com/groups/-/m/t/3142280
![enter image description here][1]
&[Wolfram Notebook][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=1917Main.png&userId=20103
[2]: https://www.wolframcloud.com/obj/29a98dca-fc92-446c-81e4-8e259d54a362Marco Thiel2024-03-17T18:00:41ZTrying to find divisors of perfect numbers (new to WL)
https://community.wolfram.com/groups/-/m/t/3147999
I asked this question on stack overflow but i think this is a better place since im using mathematica.
I'm new to coding and want to make a code in wolfram mathematica. What I want to do is decompose a perfect number into fractions for each digit.
Example for the 2nd perfect number: I want 28 to be written as 20/100 and 8/100. I want to do this for the bigger perfect numbers aswell so I need a general code.
Next I want to find the ammount common divisors of 20 and 100. (which is 6) and the amount of common divisors of 8 and 100 (which is 3).
the list I calculated found was:
1st (x) 3
2nd (y) 6 3
3rd (z) 12 4 2
4th (g) 16 9 6 4
5th (t) 64 49 42 30 0 9 4 2
6th (r) 110 90 88 49 54 30 16 0 6 2
the code i made up until now works for the 4th perfect number. from the 5th i also want to filter out the 0's and I get wrong awnsers from the 5th and up.
this is the code i made:
perfectNumber = PerfectNumber[6];
digits = IntegerDigits[perfectNumber];
numDigits = Length[digits];
positionedDigits =
MapIndexed[#1 10^(numDigits - #2[[1]]) &, digits];
dividedDigits = Map[#/10^numDigits &, positionedDigits];
divisorspower = 10^numDigits;
divisors100 = Divisors[divisorspower/10];
gcds = Map[GCD[#, divisors100] &, dividedDigits];
numeratorDivisors = Map[Divisors, gcds];
numDivisors = Map[Length, numeratorDivisors];
positionedDigitsDivisors = Map[Divisors, positionedDigits];
divisors100List =
Table[divisors100, {Length[positionedDigitsDivisors]}];
commonDivisors =
MapThread[Intersection, {positionedDigitsDivisors, divisors100List}];
numCommonDivisors = Map[Length, commonDivisors]Jasper Woutersen2024-03-26T17:00:31ZComparing computational representations of emotions (and related models)
https://community.wolfram.com/groups/-/m/t/3147541
![(Left) Visualization of an emotional space, based on the cognitive appraisal theory pioneered by Ortony et al. (Right) Modified bipartite graph representation of emotions][1]
&[Wolfram Notebook][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=modifiedgraph-imageonline.co-merged.png&userId=2579969
[2]: https://www.wolframcloud.com/obj/e8d271f7-b7cd-431a-adc4-f99755590c09Zoya Brahimzadeh2024-03-26T05:40:58Z⚠️ INTERMITTENT OUTAGES OF WOLFRAM SYSTEMS: WORKING ON RESTORATION
https://community.wolfram.com/groups/-/m/t/3148001
Wolfram systems (including Wolfram|Alpha, cloud, APIs and other websites and services) will be encountering intermittent outages. We are actively working on restoring normal functionality. We appreciate your patience and understanding.Moderation Team2024-03-26T15:22:49ZVisualizing diagrams needed to compute $\langle \operatorname{Tr}(A^3 (A^T)^3)\rangle$
https://community.wolfram.com/groups/-/m/t/3147322
(crossposted from mathematica.SE [post](https://mathematica.stackexchange.com/questions/301016/visualizing-diagrams-needed-to-compute-operatornametra3-at3))
I'm looking for help getting Mathematica code to construct diagrammatic expressions like the following, [obtained](https://math.stackexchange.com/questions/4818369/showing-e-operatornametraaatat-n3-2n) by River Li as a way to compute $\operatorname{Tr}(A^2 (A^T)^2)$ for $d\times d$ matrix $A$ with IID Gaussian entries.
[![enter image description here][1]][1]
The clearest explanation of such diagrams is given in Terry Tao's RMT [book](https://terrytao.files.wordpress.com/2011/02/matrix-book.pdf), Section 2.3.4.
He describes diagrammatic procedure for computing $E\operatorname{Tr}A^4$:
[![enter image description here][2]][2]
[![enter image description here][3]][3]
Which gives 4 different diagram types, that can be visualized method like above.
---------------
I'd like a method which takes an expression like $E \operatorname{Tr}(AAAA'A'A')$ where $A$ is a $d\times d$ matrix with IID standard normal entries, and generates a table of corresponding diagrams, [like this](https://i.stack.imgur.com/H4RVo.jpg), hand-derived by River Li.
**Background**
For the last 4 years I've been slowly organizing Mathematica-related code that helps explain Gaussian expectations (starting with 2020 post [cumulants vis](https://mathematica.stackexchange.com/questions/207183/generating-set-partition-diagrams)
, also post on [wicks brackets](https://mathematica.stackexchange.com/questions/300724/visualizing-wicks-contractions-using-brackets), [partition lattice](https://mathematica.stackexchange.com/questions/232779/visualizing-set-partition-lattice)). I'm estimating I'm about halfway done to a nice [Wolfram Community](https://community.wolfram.com/web/yaroslavvb) post on combinatorics of random matrices.
[1]: https://i.stack.imgur.com/YzAo5.png
[2]: https://i.stack.imgur.com/DXyfx.png
[3]: https://i.stack.imgur.com/14f4X.pngYaroslav Bulatov2024-03-25T17:35:16ZPrice prediction using a financial data tensor for training
https://community.wolfram.com/groups/-/m/t/3147066
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/5878dbff-119c-481d-99fe-5142b02573a4Robert Rimmer2024-03-25T15:38:43ZAhmed Integral doesn't evaluate
https://community.wolfram.com/groups/-/m/t/3145656
Why doesn't Mathematica evaluate the well-known Ahmed integral?
$$ \int_0^1 \frac{\tan ^{-1}\left(\sqrt{x^2+2}\right)}{\left(x^2+1\right)
\sqrt{x^2+2}} \, dx $$
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/8f674141-14a4-4063-a5e5-b7e8ea9c9eb5José Luis Garrido2024-03-22T07:44:29ZProblem doing a bulk import into SQL with GDELT data
https://community.wolfram.com/groups/-/m/t/3146986
Hi There,
This is a strange one (for me). I'm trying to import data from the GDELT project (http://gdeltproject.org/), one of the files is attached.
I have MS SQL installed on my PC. When I try to do bulk import from these files, I get errors about data truncating. On examining the files, it looks like there is some problems with commas in certain columns (37, 44, and 51).
If I open the files in Excel, Excel misinterprets these columns with a comma (even though this is supposed to be a tab delimited document).
When I try to do things like the following, it still fails to format the files in a way that SQL can read.
removeCommasInColumns[row_List, cols_List] := MapAt[StringReplace[#, "," -> ""] &, row, List /@ cols]
dataworldevents = Import["mypath\\20201114.export.CSV", "TSV"];
processedData = removeCommasInColumns[#, {37, 44, 51}] & /@ dataworldevents;
Export["mypath\\yourfile.csv", processedData, "TSV"];
This is the bulk upload query I'm using:
dbQuery = "BULK INSERT worldevents
FROM 'mypath\\20201114.export.CSV'
WITH
(
FIRSTROW = 1,
FIELDTERMINATOR = '\\t',
ROWTERMINATOR = '\\n',
);";
Any help would be appreciated. I'd like to import a lot of data so this seems like it would be the fastest way to do it.S G2024-03-25T13:21:35ZCan the Lucas-Lehmer primality test be implemented in Wolfram Language?
https://community.wolfram.com/groups/-/m/t/3146811
So, I recently ran across a couple lovely YouTube videos on Perfect Numbers and their relationship to Mersenne Primes, and decided to fiddle around with some stuff in Excel.
Now I'm wondering ... asking for a friend ... *cough* ... is it possible to implement some kind of efficient Lucas Lehmer testing in Mathematica either as some specific Mathematica code in a notebook or as like a core function?
Couldn't seem to find much on it. Not really familiar with prime testing or how exactly the Lucas-Lehmer test works. I assume it's some kind of advanced sieve or something that goes through a number of divisions by prime values to eliminate all possible prime divisors, or some such?
I guess part of what I wonder with respect to Mathematica is whether or not it could implement some kind of logging or start/stop type routine where it can "pick up where it left off" if interrupted ,whether due to a human closing the program, the kernel freezing, program crashing, computer rebooting, etc. IE, one wouldn't have to literally "start over from the beginning" in case of a fault or accidental action of some kind?
I know Mathematica has PrimeQ and ProvablePrimeQ functions. But, it seems like when you run them on a really large prime candidate, it just ... sits there presumably evaluating in the back ground ... but presumably that could take hours, weeks, months, years, depending how large a number one is evaluating? Like how long would a billion digit prime take to "evaluate"?
Would be cool if one could devise some kind of like logged solution that'll save its progress at regular intervals, pick up where it left off, allow some kind of inspection of what work it's already done, etc. whether it's like saving stuff to a table or some kind of log file, database, or whatever...
Just kinda' thinking out loud, as far as wish-list type stuff goes. ^_^Michael Gmirkin2024-03-25T02:06:57ZOperation of a dividing wall column and a Petlyuk column
https://community.wolfram.com/groups/-/m/t/3146882
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/96c62c1a-6c7b-4b51-962b-95340d289f37Housam Binous2024-03-25T10:16:41ZSystem identification techniques from data?
https://community.wolfram.com/groups/-/m/t/3146783
Hello,
The MatLab software has a toolbox for system identification techniques from data. What is the procedure to follow, what instructions should be used with Mathematica to have a system identification?
ThanksAndré Dauphiné2024-03-25T08:44:16ZSympathetic solar flare and geoeffective coronal mass ejection
https://community.wolfram.com/groups/-/m/t/3146725
![enter image description here][1]
&[Wolfram Notebook][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=MainImage3.gif&userId=20103
[2]: https://www.wolframcloud.com/obj/04e7c6f6-d230-454d-ac18-898ee9ea603dJeffrey Bryant2024-03-25T00:07:59ZCan Wolfram Alpha be used as a tool to learn Mathematics?
https://community.wolfram.com/groups/-/m/t/3146925
Imagine that you wanted to learn mathematics and only had access to Wolfram Alpha. Say you wanted to learn Basic Geometry. Could you learn this through Wolfram Alpha? I'm imagining a dialog between the learner and Wolfram Alpha that begins with "I want to learn Geometry", and Wolfram Alpha would start down the thread of teaching and testing that person's knowledge of geometry? Is this science fiction at this point in time?Rob Steel2024-03-24T18:53:12Z3DPlot is coming out empty
https://community.wolfram.com/groups/-/m/t/3146638
PValue = 1;
RValue = 1;
{x0Value, y0Value, z0Value} = {28, 5, 20};
kValue = 1;
{nValue, mValue, lValue} = {1, 1, 1};
dValue = 2;
(*Определение функции c*)
cFunction[x_, y_, z_, kk_] := ((x - kk)/(x - x0Value))*
Sqrt[(x - x0Value)^2 + (y - y0Value)^2 + (z - z0Value)^2]
(*Определение уравнения*)
equationFunction[x_, y_, z_, x0_, y0_, z0_] := P*R^2*\!\(
\*UnderoverscriptBox[\(\[Sum]\), \(x = kValue\), \(kValue + nValue\)]\(
\*UnderoverscriptBox[\(\[Sum]\), \(y = lValue\), \(mValue\)]\(
\*UnderoverscriptBox[\(\[Sum]\), \(z =
lValue\), \(lValue\)]\((\((1/\((\((x - x0)\)^2 + \((y -
y0)\)^2 + \((z - z0)\)^2)\)*\((
\*SuperscriptBox[\(2\), \(c/d\)])\))\))\)\)\)\)
(*Построение 3D-графика*)
Plot3D[equationFunction[x, y, z, x0Value, y0Value, z0Value, dValue,
cFunction, PValue, RValue], {x, -10, 20}, {y, -10, 20},
PlotRange -> All, AxesLabel -> {"x", "y", "Intensity"},
PlotLabel -> "3D модель"]
Initially, there was a schedule, but then for some reason it disappeared. Changed the original data, reworked the equations, but later gives an error in the form of problems with iteration. Tell me, what could be the reason?Alex Dark2024-03-24T14:22:49ZPlotting a matrix product problem
https://community.wolfram.com/groups/-/m/t/3146487
Hi I hope you are all doing well, I need to plot the results of the inverse of a matrix multiplied by another matrix, But I don't know where the problem is (I am new to Mathematica especially using tables and lists) so if any of you know how to do it it will help me a lot. Thank you all in advance.
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/2922c367-69e7-419b-a819-84b0750068d3Leo Murphy2024-03-24T13:52:59ZSimple position, velocity and acceleration notebook with dimensional checking fails?
https://community.wolfram.com/groups/-/m/t/3146381
Since physics usually involves vectors (frequently 3D) with physical dimensions. A quite frequent source of error in physics math is dimensional conflict. It is important to write out notebooks with vector elements defined with Quantity. I've been working on a very simple notebook involving position, velocity and acceleration and decided to write a convenience function to help with generating the vectors with associated magnitude variables that can be set, including setting them to functions of time so that I can define the velocity as the time derivative of position and acceleration as time derivative of velocity.
The attached notebook demonstrates the difficulty with this simple notebook.
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/7aeb8dbd-e9f3-4476-9dcd-940a29048270James Bowery2024-03-23T23:00:30ZDistillation-column product purity as function of feed thermal quality
https://community.wolfram.com/groups/-/m/t/3146544
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/cf46f393-5d67-4e65-9287-05f775b6294eHousam Binous2024-03-24T08:09:38ZT Coronae Borealis - about to go nova....again
https://community.wolfram.com/groups/-/m/t/3146524
![enter image description here][1]
&[Wolfram Notebook][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=SlideShowVideo-2024-03-23T17-32-06.gif&userId=20103
[2]: https://www.wolframcloud.com/obj/6d8866f6-af65-4f0d-a454-00bfe5fe195aJeffrey Bryant2024-03-24T03:37:22ZExploring and visualizing solutions of ordinary differential equations
https://community.wolfram.com/groups/-/m/t/3146435
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/34676387-07b7-4db5-ab60-e03210801861Athanasios Paraskevopoulos2024-03-23T21:29:04ZSolving limits without using Lhospital
https://community.wolfram.com/groups/-/m/t/3146141
hello, I use Mathematica for Calculus 1, and Mathematica uses the l hospital rule in step-by-step solutions of limit results, how can I make it solve without using l hospital and see step-by-step solutions of thisMesut Mehmet Genç2024-03-22T19:50:14ZHeat transfer in a bar with rectangular cross section
https://community.wolfram.com/groups/-/m/t/3146178
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/606dd2f7-a590-4d9b-ae59-dd8c3bad33c1Housam Binous2024-03-23T17:05:09ZDifference between Clear and ClearAll, and between '* and Global`* ?
https://community.wolfram.com/groups/-/m/t/164880
What is the difference between 'Clear' and ClearAll' and between "`*" and "Global`*" I have used ClearAll["Global`*"] and values remain attached to variables. What is the easiest way to clear all values to all variables going forward?????Raymond Low2013-12-04T08:55:22ZHow to evaluate solutions of a first order ODE system while using NDSolve?
https://community.wolfram.com/groups/-/m/t/3145953
Hello,
If one solves a single ODE by NDSolve, the following function un[t_] correctly evaluates the numerical solution obtained:
sol0=NDSolve[{u'[t]+u[t]==0,u[0]==1},u[t],{t,0,1}];
un[t_]:=Evaluate[First[u[t]/.sol0]];
un[1/2]
0.606531
My question is: how to define a corresponding function in the case of an ODE system?
My following attempt to devise an analogous function failed:
sol=NDSolve[{Subscript[u, 1]'[t]+Subscript[u, 1][t]-Subscript[u, 2][t]==0,Subscript[u, 2]'[t]-Subscript[u, 1][t]+Subscript[u, 2][t]==0,Subscript[u, 1][0]==1,Subscript[u, 2][0]==2},{Subscript[u, 1][t],Subscript[u, 2][t]},{t,0,1}];
Subscript[uns, i][t_]:=Evaluate[sol[[1]][[i]][[2]]];
Part::pkspec1: The expression i cannot be used as a part specification.
Subscript[uns, 1][1/2]
It seems that "i" must be a predefined constant, so how one can access a relevant FunctionInterpolation object corresponding to a variable "i"? Or is there a better alternative?
LesławLeslaw Bieniasz2024-03-22T19:03:26Z[?] Increase the number of rows displayed by Dataset?
https://community.wolfram.com/groups/-/m/t/1789497
Is it possible to increase the number of rows (records) displayed by Dataset? By default, only the first few rows are displayed. Which, in many cases, is fine. Especially for large datasets. However, there are often occasions when the dataset I'm working with is of moderate size and I want to display all of it. At present, I'm resorting to using Grid, but this adds work so I'd like to avoid if possible. Any suggestions would be much appreciated.Ian Williams2019-09-15T07:25:27ZNotebook for WTC23 presentation: what's new in Wolfram Video?
https://community.wolfram.com/groups/-/m/t/3145994
Hi,
Where can I find the notebook associated with this recent clip by Carlo Giacometti on new functions in video processing?
https://www.youtube.com/watch?v=bK2AO7cTbDwDinesh Rao2024-03-23T07:51:14ZGlobal population distribution: what's a Valeriepieris circle, and where 99% of us live
https://community.wolfram.com/groups/-/m/t/3024465
![enter image description here][1]
&[Wolfram Notebook][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=Leadimage2.png&userId=20103
[2]: https://www.wolframcloud.com/obj/1bbdeed3-67fe-4d71-b844-4827250a00a6Jari Kirma2023-09-30T08:43:43ZAn example of multi-level modelling in plants
https://community.wolfram.com/groups/-/m/t/3145876
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/a3858b52-b970-4bff-8b9f-a11e1b5bdad7Rui Alves2024-03-22T11:48:33ZMass balance in the Haber process
https://community.wolfram.com/groups/-/m/t/3142176
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/db3b0c55-3616-4145-8cdf-09419c0b0886Housam Binous2024-03-17T16:25:52ZController design for disturbance rejection
https://community.wolfram.com/groups/-/m/t/3146113
&[Wolfram Notebook][1]
[1]: https://www.wolframcloud.com/obj/a83ec084-cf27-475a-9d09-5ae82506e1abHousam Binous2024-03-22T17:18:23ZQuestion Regarding the Behavior of ValueQ Function in Mathematica
https://community.wolfram.com/groups/-/m/t/3145907
Hello everyone,
I've encountered an issue while using Mathematica and I'm hoping to get some clarification here. In my code, I've defined a global variable `a[b][1] = x`, and then I used the `ValueQ[a[b]]` function to check if `a[b]` has a value. However, the result I obtained is True, instead of the expected False.
&[Wolfram Notebook][1]
I've checked some references, including page 39 of the book "Mathematica Programming: An Advanced Introduction", which states that `ValueQ[a[b]]` should return False. I'm puzzled by this result and would like to understand the reason behind this behaviour.
I've tried to look through the documentation and other resources, but I haven't found a clear explanation for this situation. So, I'd like to ask the community here: Should `ValueQ[a[b]]` indeed return True in this case? If so, why is there a discrepancy between the statement in "Mathematica programming: an advanced introduction" and the actual behaviour? If not, I might be missing something, and I'd appreciate it if someone could point out my mistake and provide some assistance.
[1]: https://www.wolframcloud.com/obj/ff3dff3f-eb31-4fa1-ba89-d3a847729f9eHengjian Wang2024-03-22T07:52:57ZNDSolveValue in FEM not finish
https://community.wolfram.com/groups/-/m/t/3145804
I'm having trouble finishing the calculations in Mathematica 13.2.1.0.
I'm trying to solve a 3D heat conduction equation (a type of partial differential equation) using the FEM package, but NDSolveValue didn't finish.
The fem mesh is created as intended.
Changing MaxStepSize, WorkingPrecision, and MeshRefinementFunction did not improve the situation.
I am not sure if the code of initial conditions and boundary conditions are appropriate.
I would appreciate any advice you could give me.
Code:
Needs["NDSolve`FEM`"];
simX = 0.05;
simY = 0.03;
gapX = 0.03;
gapY = 0.01;
gapZ = 0.01;
TotalArea = Rectangle[{-simX, -simY}, {simX, simY}];
Board1 = Rectangle[{-gapX, -gapY}, {gapX, -(gapY + gapZ)}];
Board2 = Rectangle[{-gapX, gapY}, {gapX, gapY + gapZ}];
Boards = RegionUnion[Board1, Board2];
Gap = Rectangle[{-gapX, -gapY}, {gapX, gapY}];
Env = RegionDifference[TotalArea, Gap];
(* Mesh Generation *)
bmesh = ToBoundaryMesh[
"Coordinates" ->
{{-simX, -simY}, {-simX, simY}, {simX, simY}, {simX, -simY},
{-gapX, -gapY}, {-gapX, -(gapY + gapZ)}, {gapX, -(gapY +
gapZ)}, {gapX, -gapY},
{-gapX, gapY}, {-gapX, gapY + gapZ}, {gapX, gapY + gapZ}, {gapX,
gapY} },
"BoundaryElements" ->
{LineElement[{
{1, 2}, {2, 3}, {3, 4}, {4, 1},
{5, 6}, {6, 7}, {7, 8}, {8, 5},
{9, 10}, {10, 11}, {11, 12}, {12, 9},
{6, 7}, {7, 11}, {11, 10}, {10, 6}
}]},
"RegionHoles" ->
{{0, -(gapY + gapZ/2)}, {0, gapY + gapZ/2}}
]
bmesh["Wireframe"]
mesh = ToElementMesh[bmesh,
MeshRefinementFunction ->
Function[{vertices, area},
Block[{x, y}, {x, y} = Mean[vertices];
If[Abs[x] < gapX*1.5 && Abs[y] < gapY*1.5, area > 0.5,
area > 0.9 ]
]]];
mesh["Wireframe"]
c = 1006;(*(specific heat[J/kg ℃])*)
rho = 1.166;(*(density[kg/m3])*)
k = 0.0257; (*Thermal conductivity of air[W/(m K)]*)
eq = c*rho*D[T[x, y, t], t] ==
k (D[T[x, y, t], {x, 2}] + D[T[x, y, t], {y, 2}]);
T0 = 30 + 273.15;
T1 = 40 + 273.15;
ic = T[x, y, 0] ==
Piecewise[{{T1, {x, y} \[Element] Env}, {T0, {x, y} \[Element]
Gap}}];
bc = NeumannValue[0,
x == -simX || x == simX || y == -simY || y == simY];
U = NDSolveValue[{eq, ic2}, T, {x, y} \[Element] mesh, {t, 0, 1},
MaxStepSize -> 1, WorkingPrecision -> MachinePrecision];Akira O2024-03-22T04:07:12ZMemory leak of coordinate transformation functions
https://community.wolfram.com/groups/-/m/t/3144882
Hello,
I ran into some functions like "ToPolarCoordinates" that seem not to manage memory usage properly. Compared to "Norm" :
$HistoryLength = 0;
Do[
ToPolarCoordinates[{x, y, z}];
Print@MemoryInUse[],
3];
Do[
Norm[{x, y, z}];
Print@MemoryInUse[],
3];
Out:
96411880
96432720
96453368
96451496
96451496
96451496
I tried other coordinate transformation functions like "ToSphericalCoordinates" and find the same behavoir. Each call to these functions takes extra memory.
And it only occurs to symbolic evaluations. Numerical evaluation is OK:
$HistoryLength = 0;
Do[
ToPolarCoordinates[{1, 2, 3}];
Print@MemoryInUse[],
3];
Out:
96456792
96456792
96456792
Is there some sort of memory leak bug in this behavoir? Tested on MMA 13.3.1.Ming XU2024-03-21T02:34:41Z⭐ [R&DL] Wolfram R&D Developers on LIVE Stream
https://community.wolfram.com/groups/-/m/t/2593151
**Introducing our brand new YouTube channel, [Wolfram R&D][1]! Our channel features livestreams, behind-the-scenes creator presentations, insider videos, and more.**
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Join us for the unique Wolfram R&D livestreams on [Twitch][2] and [YouTube][3] led by our developers!
You will see **LIVE** stream indicators on these channels on the dates listed below. The live streams provide tutorials and behind the scenes look at Mathematica and the Wolfram Language directly from developers.
Join our livestreams every Wednesday at 11 AM CST and interact with developers who work on data science, machine learning, image processing, visualization, geometry, and other areas.
----------
⭕ **UPCOMING** EVENTS
- Mar 22 -- [20 Years of xAct Tensor Computer Algebra][58]
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✅ **PAST** EVENTS
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[53]: https://community.wolfram.com/groups/-/m/t/3009184
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[60]: https://community.wolfram.com/web/vshtabovenkoCharles Pooh2022-08-05T21:37:19ZExploration of one-dimensional Schrödinger equation solutions 2: Wavefunction & Polynomial Potential
https://community.wolfram.com/groups/-/m/t/3145353
![enter image description here][1]
&[Wolfram Notebook][2]
[1]: https://community.wolfram.com//c/portal/getImageAttachment?filename=main_image2.gif&userId=20103
[2]: https://www.wolframcloud.com/obj/7451c360-5b6c-4e20-8938-ac01d85d212fKlaus von Bloh2024-03-21T15:45:04Z