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CY Ye
CY Ye

Reputation: 23

How to read .mat output files in JModelica?

To save the time, I'm trying to read the .mat file rather than simulate the model again.

I used scipy.io.loadmat but it didn't work well:

res = loadmat('ChatteringControl_result.mat')
res.keys()

['Aclass', 'dataInfo', 'name', 'data_2', 'data_1', 'description']

The keys are not variable names, and I don't know how to get the variable values.

Then I searched for resolutions, and found DyMat, it works well for other variables but cannot get time.

res1 = DyMat.DyMatFile('ChatteringControl_result.mat')
T = res1['T']
t = res1['time']

KeyError: 'time'

So, how can I get all the results in JModelica?(Without open Matlab of course.)Like, a built-in function in JModelica?

BIG THANKS!

Upvotes: 2

Views: 556

Answers (2)

Christian Winther
Christian Winther

Reputation: 1123

To load the mat file using JModelica you can use this code:

from pyfmi.common.io import ResultDymolaBinary

res = ResultDymolaBinary("MyResult.mat")

var = res.get_variable_data("myVar")

var.t #Time trajectory
var.x #Variable trajectory

Upvotes: 3

sjoelund.se
sjoelund.se

Reputation: 3523

https://openmodelica.org/doc/OpenModelicaUsersGuide/latest/technical_details.html#the-matv4-result-file-format describes the format. I think you can also look in a Dymola manual for more details.

As for DyMat, there is no reason to get the time trajectory because you typically lookup what value a variable has at a certain time. The start and stop-times are in the data_1 matrix as far as I remember (or typically get it from the first trajectory in the data_2 matrix). (The data_2 matrix may be interpolated, so the time values stored in it may not reflect the actual steps taken internally by the solvers)

Upvotes: 3

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