Erro messages--->RE: How to combine user-defined functions with AMPL?
ZhangWeizhong
Hi, I have made the user-defined function work in my program, but I got
the message
"Warning: cutting back alpha due to evaluation error;
Warning: evaluation error during soft restoration phase step"
Does anybody in this group know this issue?
Thank you.
Weizhong Zhang
----------------------------------------
> From: grea...@hotmail.com
> To: am...@googlegroups.com
> Subject: How to combine user-defined functions with AMPL?
> Date: Mon, 17 Mar 2008 17:07:13 -0400
>
>
> Hi,
> How to make AMPL work with user-defined functions?
> I have searched the web, and found the related answers by Robert Four at
> http://groups.google.com/group/ampl/browse_thread/thread/df03ac7c8d33fa23
>
> Then I found the following information is related with my problem.
> http://www.sor.princeton.edu/~rvdb/ampl/nlmodels/
>
> "Some models require nonlinear functions that are not included with ampl . To run these models you need to download funcadd.c, compile it into a dll called amplfunc.dll, and set the shell environment variable AMPLFUNC to point to the directory containing this dll. Here's a sample makefile for building amplfunc.dll on an SGI machine: makefile.irix."
>
> The more information link is not working. "http://www.ampl.com/cm/cs/what/ampl/NEW/libload.html."
>
>
> Does anybody have solved this kind of problem before?
>
> How to compile "myfunction.c" to make it hooked with AMPL to solve the problem? Where can I found any related example or information?
> Thank you.
>
> Weizhong Zhang
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ZhangWeizhong
Hi, does anybody know how to use "iteration" information.
In my program, I need to call the part of user-defined function for one time, then for the next iteration, this part of function does not to
be called, I use a variable "checky" in this piece of function, when this function is executed, checky=checky+1.
But I have to defined "checky" in AMPL and assign the initial value "1" to checky, every iteration, checky is cleared to 1 again, it means
the function runs again.
Does anybody have this similar problem before?
Thank you first.
weizhong> Subject: [AMPL 1697] Erro messages--->RE: How to combine user-defined functions with AMPL?
> Date: Mon, 31 Mar 2008 20:57:13 -0400
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Robert Fourer
> From: am...@googlegroups.com [mailto:am...@googlegroups.com]
> On Behalf Of ZhangWeizhong
> Sent: Monday, March 31, 2008 7:57 PM
> To: am...@googlegroups.com
> Subject: [AMPL 1697] Erro messages--->RE: How to combine user-defined
> functions with AMPL?
>
> the message
> "Warning: cutting back alpha due to evaluation error;
> Warning: evaluation error during soft restoration phase step"
>
> Does anybody in this group know this issue?
It appears that AMPL is calling your user-defined function, but an error is
occurring during the execution of the function. For example, a division by
zero might be occurring. The warning messages that you observe are coming from
the solver, though. See if you can add some code to your function that catches
errors and displays some more meaningful error messages. If you're not sure
what the errors could be, you could also add some temporary debugging code to
your function to display some information each time it is called.
Bob Fourer
4...@ampl.com