[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Bug-glpk] Re: [Help-glpk] Incorrect result (bug) or programming issu
[Bug-glpk] Re: [Help-glpk] Incorrect result (bug) or programming issue?
Mon, 21 Mar 2005 15:54:41 +0300
To fix the bug please replace line 4990 in file glpmpl3.c (glpk 4.8):
write_text(mpl, from, (int)(value + 0.5));
by the following one:
write_text(mpl, from, (int)floor(value + 0.5));
and then recompile/reinstall the package in a usual way.
Note that the bug will be fixed in a next release of Glpk.
The bug appears if the value to be printed is negative and %d format
specifier is used. The value should be properly rounded to the nearest
integer while it was simply truncated.
So, in your case it was (int)(-6 + 0.5) = (int)(-5.5) = -5 while the
correct answer is obviously -6.
Reading model section from bug.mod...
23 lines were read
Model has been successfully generated
lpx_simplex: original LP has 5 rows, 4 columns, 13 non-zeros
lpx_simplex: presolved LP has 4 rows, 4 columns, 9 non-zeros
lpx_adv_basis: size of triangular part = 4
* 0: objval = 0.000000000e+00 infeas = 0.000000000e+00 (0)
* 3: objval = 1.750000000e+01 infeas = 0.000000000e+00 (0)
OPTIMAL SOLUTION FOUND
Integer optimization begins...
Objective function is integral
+ 3: mip = not found yet <= +inf (1; 0)
+ 4: mip = 1.700000000e+01 <= 1.700000000e+01 0.0% (2; 0)
+ 4: mip = 1.700000000e+01 <= tree is empty 0.0% (0; 3)
INTEGER OPTIMAL SOLUTION FOUND
Time used: 0.0 secs
Memory used: 0.1M (151244 bytes)
x1=0, x2=5, x3=-6, x4=9
Model has been successfully processed
|[Prev in Thread]
||[Next in Thread]|
- [Bug-glpk] Re: [Help-glpk] Incorrect result (bug) or programming issue?,
Andrew Makhorin <=