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[Help-glpk] Re: GLPK4 DELPHI


From: Andrew Makhorin
Subject: [Help-glpk] Re: GLPK4 DELPHI
Date: Sun, 8 Feb 2004 12:41:39 +0300

>   Everything is quiet  correct  ( your basic example 'p q r ' is Ok ) ....
>      just a big problem if there is ANY ZERO in the MATRIX-CONSTRAINTS ( 
> row*col ) .... 
>          Your programm stops  in : lpx_load_mat3(lp, Nb, rn, cn, pMatLC);   
> where pMatLC is a pointer to the MATRIX...
>                ( ...._lib_default .... ).
>          If I replace all ZERO by (10^-xxx) - a tiny number - it works very 
> well ....( 10^-300 is the limit I try ..... )
>
>          Do You know the reason of this ???

Zero constraint coefficients are not allowed. You should remove them
from the coefficient list before call to lpx_set_mat_row,
lpx_set_mat_col, or lpx_load_matrix (lpx_load_mat3 in glpk 4.3).
Replacing zeros by tiny numbers is not a good idea, because this may
cause numeric difficulties.






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