> Could anyone perhaps give me some literature pointers (preferrably
> freely available on the net)
> on how to achieve this "well-conditioned" situation, or some examples?
> I was playing a bit with
> scaling variables and it seems to improve things a bit, but I am
> probably reinventing the wheel
On Tue, Jul 29, 2008 at 3:53 PM, Andrew Makhorin <[EMAIL PROTECTED]> wrote:
>>> Probably this happens because your instance is not well conditioned,
>>> so due to excessive round-off errors the presolved lp is unbounded
>>> while the original lp is not.
>> What does "not well conditioned" mean? Wha
> Did you plan to include this new version of glp_simplex in 4.30 ?
I plan to replace implementation of the primal simplex by a new
version, however, I am not sure about 4.30, because the new routine
is still under development.
___
Help-glpk mailing l
Andrew,
Did you plan to include this new version of glp_simplex in 4.30 ?
[]'s
Haroldo
On Tue, Jul 29, 2008 at 10:53 AM, Andrew Makhorin <[EMAIL PROTECTED]> wrote:
> >> Probably this happens because your instance is not well conditioned,
> >> so due to excessive round-off errors the presolved l
Thanks, your explanation has been very helpful. I am trying to improve the form
of my LPs and it seems to work in most cases.
Marcin
On Tue, Jul 29, 2008 at 3:53 PM, Andrew Makhorin <[EMAIL PROTECTED]> wrote:
>>> Probably this happens because your instance is not well conditioned,
>>> so due to e
>> Probably this happens because your instance is not well conditioned,
>> so due to excessive round-off errors the presolved lp is unbounded
>> while the original lp is not.
> What does "not well conditioned" mean? What can I do about it?
Ill-conditioning means, roughly speaking, that small chang
> Probably this happens because your instance is not well conditioned,
> so due to excessive round-off errors the presolved lp is unbounded
> while the original lp is not.
What does "not well conditioned" mean? What can I do about it?
>
>> Also neither lpx_adv_basis nor lpx_std_basis
>> seem to s
> Thanks, I changed it and I can kind of reproduce glpsol's behaviour,
> but now I pinpointed the problem to this LP:
> http://www.mimuw.edu.pl/~mucha/lpQ_bad.txt
> glpsol --cpxlp lpQ_bad.txt
> give UNBOUNDED solution here. However, both
> glpsol --std --cpxlp lpQ_bad.txt
> and
> glpsol --adv --cpx
Thanks, I changed it and I can kind of reproduce glpsol's behaviour,
but now I pinpointed the problem to this LP:
http://www.mimuw.edu.pl/~mucha/lpQ_bad.txt
glpsol --cpxlp lpQ_bad.txt
give UNBOUNDED solution here. However, both
glpsol --std --cpxlp lpQ_bad.txt
and
glpsol --adv --cpxlp lpQ_bad.txt
> Hello, I have glpk 4.25 installed on my Ubuntu and I am having trouble
> with solving some LPs while glpksol solves them fine. I was trying to
> reproduce glpksol's behaviour in my C++ program but couldn't do it.
> What options should I use with glp_simplex to get the exact same
> behaviour as gl
Hello, I have glpk 4.25 installed on my Ubuntu and I am having trouble
with solving some LPs while glpksol solves them fine. I was trying to
reproduce glpksol's behaviour in my C++ program but couldn't do it.
What options should I use with glp_simplex to get the exact same
behaviour as glpksol?
Ma
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