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[Bug-glpk] [Fwd: infinite loop doing /* restart the search */ with Warni
From: |
Andrew Makhorin |
Subject: |
[Bug-glpk] [Fwd: infinite loop doing /* restart the search */ with Warning: numerical instability] |
Date: |
Fri, 04 Jan 2013 16:23:24 +0400 |
-------- Forwarded Message --------
From: Jan Kolar <address@hidden>
To: address@hidden
Subject: infinite loop doing /* restart the search */ with Warning:
numerical instability
Date: Fri, 04 Jan 2013 07:24:19 +0100
Hello,
I have forced (very recent) glpk into endless loop in _glp_spx_primal().
I think the problem is in glpk-4.47/src/glpspx01.c
2652 rigorous = 5;
2653 goto loop;
Somethink like the following would make more sense to me
if (rigorous < 5) {
rigorous = 5;
goto loop;
} else {
// I do not know. Proceed as it is or return
with an error ?
// In my application: relax the tolerances slightly
and loop once(1) more.
}
I appreciate any fast reply to this, thank you.
---
The data size is small (m = 20, n = 9, nnz = 87), the problem extremely
difficult.
(In my application I iterate to ask glpk for which parameter the problem
is solvable :-).)
The symptom is that glpk endlessly prints Warning: numerical
instability (primal simplex,...
Also I would suggest if memory allocations are right, since in this loop,
probably libglpk crashed my Win7+cygwin computer (after it produced 1.4
GB of "Warning: numerical instability" of output. Note: 100G free disk
space after.)
I can send program generating the input data, if it is necessary.
(starting_point_id = 4-130-130-125-162-116-147-191-159-019- )
Jan Kolar
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