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Kai Häberle (wharfish)
New member
Username: wharfish

Post Number: 1
Registered: 07-2009
Posted on Wednesday, July 22, 2009 - 10:12 am:   

Hello everybody,

I want to create a heterogenously distributed material parameter controlled by pseudorandom numbers and position. If I include the radnom function in the definitions part, I always get the message that it can't be differentiated.

Does somebody have a good idea?
Thanks!
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Robert G. Nelson (rgnelson)
Moderator
Username: rgnelson

Post Number: 1281
Registered: 06-2003
Posted on Wednesday, July 22, 2009 - 02:48 pm:   

The standard behavior of FlexPDE is to store functional definitions and re-evaluate them as needed over the domain of the problem.

This procedure is not appropriate for Random values, because it generates a new random number at each evaluation, and cannot be differentiated.

There is a qualifier CONST() which declares its argument to be a constant value, which is to be generated once and never changed.

This qualifier allows you to generate random parameters which are then held constant for the duration of the run.

Use CONST(RANDOM(size)) and your difficulties should be cured.

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