In the April 19 Files posted there is a "Readme" file. What is that?

Hello, Ankit especially you and for sure the team must be exhausted by these sessions. Thanks a lot.

My question today is,

In the CriticalToData session I unfortunately overwrote the "inf" symbol in the totalVoters component. I wrote inf into the field but that seems to be an error. Can you say how to put infinity into a field?

Thanks, John.

In regard of the mass of CO2 in the atmosphere in the year 2002:

rs1 = Solve[
   Eliminate[{xCO2 == nCO2/nAir, mAir == nAir*MAir, 
     mCO2 == nCO2*MCO2}, {nCO2, nAir}], mCO2][[1]]

gives

{mCO2 -> (mAir MCO2 xCO2)/MAir}

With data from Wolfram Alpha and Mathematica:

UnitConvert[
mCO2 //. 
Join[rs1, {mAir -> 
WolframAlpha[
"mass of atmosphere", {{"Result", 1}, "ComputableData"}], 
MCO2 -> ChemicalData["CO2", "MolarMass"], 
MAir -> ChemicalData["Air", "MolarMass"], 
xCO2 -> UnitConvert[
WolframAlpha[
"global carbon dioxide concentration 2002", {{"Result", 4}, 
"ComputableData"}][[2, 3]]]}], "MetricGigatons"]

gives

Quantity[2915.77, "MetricGigatons"]

After the study group's end, for how long would we still be able to re-watch the videos?

Hi Ankit,

Still no recording of yesterday's class is available (lol). I must study it before today's class. How can I do it?

THANK YOU, Ankit!

You are the best instructor ever!

Hi Soomi,

We will cover SystemModelCalibrate in tomorrow's session.

@Vedat Senol was sick last week. If he feels better then he should join from tomorrow.

Hi James,

Thanks for reporting, I have asked our team to look into it.

Also the options like Frame->None are not recognized... The word "Frame" comes out in red font. Also if I use "false" same result...

OK so I answered my second question: The suggestion bar at the bottom of the graph is not creating a list of options. If I place the curly bracket like you did manually, it will accept the Frame->False or None options. I don't know if that's a bug with WL 14 or SM 14, but it's not working the way it should. I'm running both on a MAC.

Further to the above Carl, ...

You should also ensure the the lesson library is automatically loaded when SM starts,

Tools > Options > Global > Modelica Libraries > Add a library Then navigate to the directory that contains ModelingPrinciples.mo

John

Perhaps @Sergio Vargas can respond to this tomorrow.

Hello Ankit,

I had troubles during the steps in WM 14 in the Start simple session. The solutions.step5 model crashed. Was this a common experience? Edit - I went back to this and found the problem, no need to answer.

I have a question also. Can you show how to save parameter adjustments made in Simulate back to the model?

Thank you, John

This has been the best set of classes on System Modeler that I've seen so far, and it's opening my eyes to what is possible. I see cool examples out of mechanical engineer and other disciplines. I'd be curious to see some canonical problems in electrical engineering solved. You can do lumped elements but I think you could create boxes that have lumped elements inside of them. RLC circuits or microwave resonator cavities. It would be fun to build a garage of "stuff". Like measure the amplitude and phase pass-band response of a band-pass filter where you can add resonators to extend it's performance and equalize its phase response. Or computing the phase noise of an analog synthesizer with a phase locked loop. And a digital version too. Quantization spurs of an ADC. Intermodulation products of an amplifier operating near compression. That sort of thing. Or maybe a test bench, where you could have a vector signal analyzer that could plot the constellation and the eye diagram of a noisy QPSK signal.

Thanks! And I will definitely be looking at that circuits course.

I installed System Modeler version 14 and then Mathematica version 14. After that, I started System Modeler and opened ModelingPrinciples. Then,

Unresolved dependency in ModelingPrinciples ModelingPrinciples has a declared dependency on BusinessSimulation version 2.2.0-wsm. No version of BusinessSimulation is currently loaded.

Would you tell me why it occurred and how to fix it? The day before, I installed System modeler only and started the System Modeler to open ModelingPrinciples. Then, the same error occurred. I though that it might be because I did not instsall Mathamatica. However, now I know that it was not the reason for it.

I opened the ModelingPrinciples. Then, only grided blank with Model 1 shows. The same error occurred - i.e., no difference of Mathematica installation.

If anyone knows about why it occurred and how to fix it, would you help me on it?

I posted the question during the class yesterday, but did not get the answer.

Am I the only one who has the strange error?

I already found it soon after I posted the question :) Now I have the Businss Simulation Library installed in System Modeler. However, I can't change the name of Model. Your Model name is "ModelingPrinciples.Coffee.Exercises.Step1." My Model was named as "Model 1" when I opened "ModelingPrinciples." I have not been able to find how to change the Model's name. I even removed System Modeler, Mathematica, and models that I created to follow your lectures and started from the first beginning to downlod them. However, I still have the same issue. Why am I the only one who raises the issue? Am I the only one who has it? Or, am I the only one who asks about it?

I will try to cover this is today's session.

Thanks for the trial version of SM 14 it permits easily to follow along.

Granted this question is most likely not part of this training, however I ask in case you can lead me to a good reference on structuring a new Media in Modelica. The media I'm interested in are range from in-compressible liquid, compressible single and multi-component gases, and refrigerants. I find it quite hard to work through the Modelica supplied documentation so am hoping someone on this forum can point out a more comprehensive explanation of how to create such media models (packages).

Hello Ankit, Thank you for sharing that file. Indeed, you created it after the most recent training session. It was sent to me then as well. Inspiring to say the least. At the time I was using version 13 of WM and SM so had to edited your file to work with those versions.

Still it's daunting to look through the Modelica files to understand how the equations of state were programmed, surely someone must have created a better documentation. I'll keep looking.

Great job, with this training. It's the best so far. John.

Hi Carl,

Not from System Modeler, but you can create such diagrams (Sankey diagram) using the Wolfram Language.

Once you are done with the simulation, you can extract the results from your simulation in Wolfram Language. Then use the results to create such diagrams. Here are some implementations that might be useful:

https://mathematica.stackexchange.com/questions/166439/how-to-make-a-sankey-diagram https://resources.wolframcloud.com/FunctionRepository/resources/AlluvialChart/

I am aware of some work going on in that direction. Hopefully, in a future release.

The easiest way of recognising inputs and outputs, for example, in a give component, is by looking at the connectors that are available in the icon of the component. Depending on the physical quantity, the connectors have different graphical representations. These are usually triangles of different colours.

In a broader sense, if you write your models, you can make any variable and input, output or none. When you make a variable input or output, there are some restrictions applied to it. For example, you will get an error when trying to connect outputs to outputs. It’s like an extra level of safety when creating your model.

All the variables are calculated when simulation is running, and the inputs will be calculated based on the output that you have connected to it. There is a special case, a top-level input, which is an input in the highest hierarchy of your model. In that case, if left unconnected, it will take a default value of zero.

Hi John,

Thank you!

1. I am not able to follow the question. To view the icon of a model or a component, you can open the model by double-clicking on it then press Ctrl + 1 to view the Icon and Ctrl + 2 to get back to the diagram view. You can refer to Step 1 in the Solution folder to check if your Step 1 in the Exercises folder matches it.

2. I will probably cover the new file creation and the .sme file on Thursday next week. No, there is no requirement to save the .sme file with the model files.

Dear Ankit Naik

Great presentation today! I kind request. If there is the opportunity, please talk about taking advantage of the large amounts of models that have been developed in Modelica language that can be imported from Wolfram SystemModeler.

Best regards

Jesus

How does Wolfram System Modeler compare to Matlab's SimuLink?