Re: [Help-glpk] expressing a constraint depending on a boolean variable
On Wed, 4 Nov 2015, Heinrich Schuchardt wrote: Hello Esma, please, see https://en.wikibooks.org/wiki/GLPK/Modeling_tips#Big_M Be sure take the advice to use the smallest M that you know works. Done right, you will get the convex hull of allowed solutions. -- Michael henne...@web.cs.ndsu.nodak.edu "Sorry but your password must contain an uppercase letter, a number, a haiku, a gang sign, a heiroglyph, and the blood of a virgin." -- someeecards___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
Re: [Help-glpk] expressing a constraint depending on a boolean variable
Hello Esma,
please, see
https://en.wikibooks.org/wiki/GLPK/Modeling_tips#Big_M
Best regards
Heinrich Schuchardt
http://www.xypron.de
Gesendet: Mittwoch, 04. November 2015 um 09:44 Uhr
Von: "esma mehiaoui"
An: "GLPK Help List"
Betreff: [Help-glpk] expressing a constraint depending on a boolean variable
Hello everyone,
Please could you help me to express the following constraint if possible.
for i in {1..2} if V[i] =1 then 2<= sum {x in MySet} V2[x] <=3
else (V[i] =0) then sum {x in MySet} V2[x] may have any value (i do not care about the value in this case)
with V and V2 are boolean variables
Thank you in advance
Esma
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Re: [Help-glpk] Using GLPK on windows 8
On Wed, 2015-11-04 at 16:07 +0300, Andrew Makhorin wrote: > > I followed the instruction as you told, > > But I still don't know how to execute " .mod" file using Visual > > Studio, the glpk.h was included. > > > > (I want to apply glpk for my " .mod" files from my Mac in Window ) > > > > If you has successfully built glpk, there must be glpsol.exe in > subdirectory 'w32' or 'w64'. Just run it from the command line as > follows: > >glpsol -m foo.mod > > For more details please see the glpk manual. > > FYI: you can download precompiled glpk binaries (including the glpsol > program) for MS Windows from http://winglpk.sourceforge.net/ . Also look at http://gusek.sourceforge.net/gusek.html . Maybe it is just you need. ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
Re: [Help-glpk] Using GLPK on windows 8
> I followed the instruction as you told, > But I still don't know how to execute " .mod" file using Visual > Studio, the glpk.h was included. > > (I want to apply glpk for my " .mod" files from my Mac in Window ) > If you has successfully built glpk, there must be glpsol.exe in subdirectory 'w32' or 'w64'. Just run it from the command line as follows: glpsol -m foo.mod For more details please see the glpk manual. FYI: you can download precompiled glpk binaries (including the glpsol program) for MS Windows from http://winglpk.sourceforge.net/ . ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
Re: [Help-glpk] expressing a constraint depending on a boolean variable
> Please could you help me to express the following constraint if
> possible.
>
>
> for i in {1..2} if V[i] =1 then 2<= sum {x in MySet} V2[x] <=3
> else (V[i] =0) then sum {x in MySet} V2[x] may
> have any value (i do not care about the value in this case)
>
>
>
>
> with V and V2 are boolean variables
>
The disjunctive condition
if z = 1 then a <= x <= b
if z = 0 then -M1 <= x <= +M2
where M1 and M2 are sufficiently big numbers, is equivalent to:
a * z - M1 * (1 - z) <= x <= b * z + M2 * (1 - z)
from which it follows that:
x >= (a + M1) * z - M1
x <= (b - M2) * z + M2
Note that M1 = - inf x, and M2 = + sup x should be chosen as small as
possible.
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[Help-glpk] expressing a constraint depending on a boolean variable
Hello everyone,
Please could you help me to express the following constraint if possible.
for i in {1..2} if V[i] =1 then 2<= sum {x in MySet} V2[x] <=3
else (V[i] =0) then sum {x in MySet} V2[x] may have any value (i do not care
about the value in this case)
with V and V2 are boolean variables
Thank you in advanceEsma___
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