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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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problem of user defined function

Posted 2013年3月4日 GMT-5 22:19 Version 4.3a 4 Replies

Chaney Long
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I am using poroelasticity module. I defined a analytic function named G. It is a function of poro.eZ (strain component in z direction), G=f(poro.eZ), and I can plot out the figure of the G(poro.eZ) correctly. But when I try to compute the model, there is an error, the screen shot of which is attached.

What is the meaning of "Function: dmod1.G_dporo.eZ"?

Anyone can tell me what is the problem of that? Any suggestions to solve this error? thanks a lot!

Attachments:

4 Replies Last Post 2013年3月6日 GMT-5 09:24
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2013年3月5日 GMT-5 00:53
Hi

strange, you must have a typo somewhere, or an internal pointer error in the file.

But I would, just to be sure, use another name as "G" might be used by COMSOL, internally

--
Good luck
Ivar
Hi strange, you must have a typo somewhere, or an internal pointer error in the file. But I would, just to be sure, use another name as "G" might be used by COMSOL, internally -- Good luck Ivar
Chaney Long
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Posted: 1 decade ago 2013年3月5日 GMT-5 08:48

Hi

strange, you must have a typo somewhere, or an internal pointer error in the file.

But I would, just to be sure, use another name as "G" might be used by COMSOL, internally

--
Good luck
Ivar


Thanks Ivar,

I have actually tried change the name of the function into other name, like "S", but there is still the same problem. If there is a typo, I think I can not plot out the figure of G vs. poro.eZ, but actually it can be correctly plot out.

Do you know what is the meaning of the character "d" in the error function of "dmod1.G_dporo.eZ"? Does it mean derivative?

Sometimes, another error showed (attachment).
[QUOTE] Hi strange, you must have a typo somewhere, or an internal pointer error in the file. But I would, just to be sure, use another name as "G" might be used by COMSOL, internally -- Good luck Ivar [/QUOTE] Thanks Ivar, I have actually tried change the name of the function into other name, like "S", but there is still the same problem. If there is a typo, I think I can not plot out the figure of G vs. poro.eZ, but actually it can be correctly plot out. Do you know what is the meaning of the character "d" in the error function of "dmod1.G_dporo.eZ"? Does it mean derivative? Sometimes, another error showed (attachment).

Attachments:

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2013年3月6日 GMT-5 01:04
Hi

no idea what the "d" is except if you have renamed the "mod1" identifier to "dmod1"

now do not forget that poro.eZ is a "field" hence its poro.eZ(x,y,z,t) (or depending on "r" if in 2D-axi) so when you evaluate G(poro.eZ) you need to have a geometrical Entity defined, onto which the field poro.eZ is evaluated

--
Good luck
Ivar
Hi no idea what the "d" is except if you have renamed the "mod1" identifier to "dmod1" now do not forget that poro.eZ is a "field" hence its poro.eZ(x,y,z,t) (or depending on "r" if in 2D-axi) so when you evaluate G(poro.eZ) you need to have a geometrical Entity defined, onto which the field poro.eZ is evaluated -- Good luck Ivar
Chaney Long
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Posted: 1 decade ago 2013年3月6日 GMT-5 09:24

Hi

no idea what the "d" is except if you have renamed the "mod1" identifier to "dmod1"

now do not forget that poro.eZ is a "field" hence its poro.eZ(x,y,z,t) (or depending on "r" if in 2D-axi) so when you evaluate G(poro.eZ) you need to have a geometrical Entity defined, onto which the field poro.eZ is evaluated

--
Good luck
Ivar


Hi Ivar,

My model's name is "mod1" not "dmod1".
I use 2D-axi model. I think poro.eZ represents the strain in the z direction of the geometry. I defined function as G=f(poro.eZ).
Sometimes, it will show error "failed to evaluate temporary symbolic derivative variable", what does that mean?
Thanks a lot!

[QUOTE] Hi no idea what the "d" is except if you have renamed the "mod1" identifier to "dmod1" now do not forget that poro.eZ is a "field" hence its poro.eZ(x,y,z,t) (or depending on "r" if in 2D-axi) so when you evaluate G(poro.eZ) you need to have a geometrical Entity defined, onto which the field poro.eZ is evaluated -- Good luck Ivar [/QUOTE] Hi Ivar, My model's name is "mod1" not "dmod1". I use 2D-axi model. I think poro.eZ represents the strain in the z direction of the geometry. I defined function as G=f(poro.eZ). Sometimes, it will show error "failed to evaluate temporary symbolic derivative variable", what does that mean? Thanks a lot!

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