I am trying to solve a MIP model (GMPL language), but I want to use the GLPSOL options to limit the search duration (by setting a gap tolerance).

I found this on the GLPK Wiki:

glpsol –cuts –fpump –mipgap 0.001 –model problem.mod –data problem.dat

How can I enter this –mingap functionality in Excel? Since I am here editing the .mod file I believe?

Thanks,

Alex

when I try to output a 1-dimensional parameter to my excel file, I keep getting errors. The syntax (from example file) works for a 2-dimensional array! Do you have an idea what is wrong with my syntax?

printf “” > “Sheet”; # Open output file

printf “Sourcing :=\n” >> “Sheet”;

printf {i in DistributionCenters, j in Customers}: “‘%s’ ‘%s’ ‘%s’\n”, i, j, Sourcing[i,j] >> “Sheet”;

printf “;\n” >> “Sheet”;

printf “DCCheckBinary :=\n” >> “Sheet”;

printf {i in DistributionCenters}: “‘%s’ ‘%s’ ‘%s’\n”, i, DCCheckBinary[i] >> “Sheet”;

printf “;\n” >> “Sheet”;

Here it works to output the Sourcing array (2-dim), but the DCCheckBinary array (1-dim) does not work.

Any help is welcome,

Thanks

Agnew

http://www.gurobi.com/resources/examples/mining

i am trying to replicate this example in solver studio but it doesn’t work. its meant to be python.

]]>E.g.:

* 44: obj = 2.211556871e+05 inf = 0.000e+00 (0)

OPTIMAL LP SOLUTION FOUND

Integer optimization begins…

+ 44: mip = not found yet >= -inf (1; 0)

+ 49: >>>>> 3.066614637e+05 >= 2.211556871e+05 27.9% (3; 0)

+ 74: mip = 2.253335908e+05 >= tree is empty 0.0% (0; 17)

INTEGER OPTIMAL SOLUTION FOUND

Thanks in advance

]]>I have been using opensolver on many instances with great satisfaction. Thank you for making LP available on excel. I have now to solve a problem of the type of the warehouse-bars transportation one, with a large warehouse/bar cost matrix, and would like to use solverstudio for this. In order to speed-up the calculation, I would like to fix to zero some of the elements of the warehouse-bar solution matrix – typically those corresponding to routes too long to be used. Which modeling language should I use to make sure that this variable fixing results in a reduction of the number of optimization variables? I understand that AMPL does this, but AMPL limits the number of variables in its free version. Is there another modeling language -free of use- which shares this feature? ]]>