[Coin-discuss] arithmetic exception when using Cbc

[John J Forrest]

I hope it is now fixed on trunk.  I have put changes into my local copy in
branches/devel and that should be updated soon.

John Forrest


                                                                           
             Kish Shen                                                     
             <kish.shen at crossc                                             
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                                       [Coin-discuss] arithmetic exception 
                                       when using Cbc                      
             11/02/06 11:28 AM                                             
                                                                           
                                                                           
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Hi,

I am getting an arithmetic exception when using Cbc/Clp through OsiClp. The
crash happens in
CbcModel.cpp, in gcd (line 84 in the copy I am using):

  while (remainder) {
    remainder = b % a;
    b = a;
    a = remainder;
  }
  return b;

The crash happens  in doing the % operation, I assume because a = -1.

This is within a call to a call to CbcModel's branchAndBound().

I am using Cbc/Clp as an MP solver for the Constraint Logic Programming
Language ECLiPSe,
for which I am providing an interface. The original problem occurs in a
program of one of our
users, and it happens after repeated solving and modification of the
problem.

I have extracted the C/C++ calls to Osi/Cbc that reproduce this problem
without ECLiPSe. The
file is quite big, nearly 300K in size, so I am not including it with this
message.

I get this error with a copy of the development branch of Cbc I donwloaded
on 2006-08-17. I have
just tried to run the same code with the latest development branch which I
downloaded
today (2006-11-02), but the program aborts much earlier. I haven't been
able to look at why this
happens yet.

Does this problem look like it might be something that I am doing wrong, or
something that
might have been fixed since August?

I guess John Forrest might be interested in looking at the code that give
this problem. Do
please let me know, and I can send the code to you.

Thanks in advance for any information and help!

Kish Shen


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