MATLAB: Is the logged dataset variable empty

simulink

Why is my logged dataset variable empty?

I recently upgraded to R2015b and tried running my model, but I received a warning that said I should use the "Dataset" format instead of the "ModelDataLogs" format. I fixed this, but then my data analysis scripts stopped working.

I double clicked the logged dataset variable in the MATLAB base workspace, but only saw the name of the dataset and when I double clicked on the "Name" property, I only saw the character string contained in that name when I was expecting many logged variables containing data.

Best Answer

As of R2016a, the "ModelDataLogs" format has been replaced by the "Dataset" format, so that is why there is a warning when if you try to use the "ModelDataLogs" format.

Upgrading the model and any related data analysis files is not as simple as changing the logging format in the Model Configuration Parameters because "Dataset" objects behave differently from "ModelDataLogs."

Here is the Simulink Documentation page showing how to migrate from "ModelDataLogs" to "Datasets".

https://www.mathworks.com/help/simulink/ug/enabling-signal-logging-for-a-model.html

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MATLAB: Is the fimplicit plot empty

The warning means, that Matlab did not find an analytical solution - solve numeric:

syms x(t) Dxt(t)
ode = diff(x,t,2) + ((4.2/(t + 3))/2)*x == 0;
[ode, vars] = reduceDifferentialOrder(ode, x);
[V, S] = odeToVectorField(ode);
fun = matlabFunction(V,'Vars',{'t','Y'});
[t, xSol] = ode45(fun,[0 200],[0 5]);
plot(t,xSol)
grid on;

MATLAB: How to convert ModelDataLogs to Structure

This might help. Assume your logged data is "logsout", run

logsout.unpack('all') to unpack all the data and then do whatever conversion you want.

doc unpack

Best Answer

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MATLAB: Is the fimplicit plot empty

MATLAB: How to convert ModelDataLogs to Structure

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