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Hello Johan Gustafsson

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Did you figure it out?

No, unfortunately I have not. I worked around the problem by calculating the variables in MATLAB first and then assigning the final value to the COMSOL model. But it would still be nice to be able to get this to work.

Johan

Hi,

If I have a parameter, e.g.:

>> model.param.set('outer_z', '((volume*formfactor^2)/(2*pi))^(1/3)');

How can I in the easiest way evaluate the value of this parameter (like the 'Value'-column in the GUI)?

I get an error message when trying to use:
>> mphglobal(model,'outer_z')
"com.comsol.util.exceptions.FlException: Unknown dataset feature"

Regards,
Johan

The function mphglobal(model,'parameter_name') works for me when calculating parameter values. Maybe there is a problem in your definition of ((volume*formfactor^2)/(2*pi))^(1/3), check that all the parameters are set.

Bye.

Hi everyone,
Sorry for bring back such an old discussion but I'm having the same problem (unknown data set). I think this problem somehow relates to having not initialized the model (but I'm not sure how). Since it cannot find a dataset to evaluate the string in. Anyone know what I'm missing? Consider the simple striped down MATLAB script below which returns the same error. Interestingly enough model.param.get('test_param_a') will return the original string.

Thanks in advance,
Andrew


import com.comsol.model.*
import com.comsol.model.util.*

model = ModelUtil.create('Model');
model.modelPath('F:\FAST\MATLAB');
model.modelNode.create('mod1');

model.geom.create('geom1', 2);
model.geom('geom1').axisymmetric(true);

model.mesh.create('mesh1', 'geom1');

model.param.set('test_param_a', '1[mm]');

temp = mphglobal(model,'test_param_a')

Hi,

If I have a parameter, e.g.:

>> model.param.set('outer_z', '((volume*formfactor^2)/(2*pi))^(1/3)');

How can I in the easiest way evaluate the value of this parameter (like the 'Value'-column in the GUI)?

I get an error message when trying to use:
>> mphglobal(model,'outer_z')
"com.comsol.util.exceptions.FlException: Unknown dataset feature"

Regards,
Johan

I'm also having the same problem, has anyone figured this out?

Thanks,
Mark

It has been a while since I worked with the LiveLink for Matlab. To get a parameter (pellet_length) from Comsol to Matlab I used the following commmand:

pellet_length = mphevalglobalmatrix(model,'pellet_length');

Not sure if this applies only to parameters, or if there is a better way of doing this, but it worked for me.

It has been a while since I worked with the LiveLink for Matlab. To get a parameter (pellet_length) from Comsol to Matlab I used the following commmand:

pellet_length = mphevalglobalmatrix(model,'pellet_length');

Not sure if this applies only to parameters, or if there is a better way of doing this, but it worked for me.

Andrew. Thanks a lot! It turns out that I was able to get
mphglobal(model,'outer_z')
to work too. So it appears I'm in good shape now.

Thanks!
Mark

model.param.get('outer_z') should work