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conditional expression "if"

Posted Feb 22, 2011, 9:36 a.m. EST Parameters, Variables, & Functions Version 4.1 3 Replies

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it is possible to use an conditional expression "if" in an analitic function?
3 Replies Last Post Mar 10, 2011, 9:58 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Feb 22, 2011, 9:54 a.m. EST
Hi

mostly yes, try it.
But be aware that expressions and functions should ideally be derivable once or even better twice, so use with sens and try to keep your function continuous to avoid convergence issues

--
Good luck
Ivar
Hi mostly yes, try it. But be aware that expressions and functions should ideally be derivable once or even better twice, so use with sens and try to keep your function continuous to avoid convergence issues -- Good luck Ivar
Adam Collins
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Posted: 1 decade ago Mar 10, 2011, 8:21 a.m. EST
Hi,

I'm having trouble with the 'if' operator.
Would you mind explaining what you mean by combining it with the 'sens' operator please?
I tried to combine the two but I am getting errors.

Thanks!
Hi, I'm having trouble with the 'if' operator. Would you mind explaining what you mean by combining it with the 'sens' operator please? I tried to combine the two but I am getting errors. Thanks!
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 10, 2011, 9:58 a.m. EST
Hi

sorry that was my floppy and too quick writing there is no sens operator, its just that an if operator makes often step functions and you should avoid steps, but make the transition smooth with a heaviside combination, easy in V4 because step functions or pulse functions with smoothing are "built in" see the functions tab under Definitions

--
Good luck
Ivar
Hi sorry that was my floppy and too quick writing there is no sens operator, its just that an if operator makes often step functions and you should avoid steps, but make the transition smooth with a heaviside combination, easy in V4 because step functions or pulse functions with smoothing are "built in" see the functions tab under Definitions -- Good luck Ivar

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