Suppress mixed integer programming output [closed]

asked 2021-09-20 06:38:57 +0200

zjs gravatar image

updated 2021-09-21 06:45:58 +0200

I am running code on a remote server in which I solve many small mixed integer programs(using the .solve() method). I tested my code on my local machine with no issues. However, when I run it remotely it seems that the Sage installation there does not suppress output from .solve(). I get many, many prints to the console which look like:

glp_exact: 224 rows, 196 columns, 588 non-zeros
GNU MP bignum library is being used
      0:   infsum =                      2   (11)
     47:   infsum =                      0   (11)
*    47:   objval =       1.39285714285714   (12)
*   205:   objval =      0.660714285714286   (5)
OPTIMAL SOLUTION FOUND

It would be very helpful to not have Sage constantly printing to the console; is there a way to suppress this output? Some sort of flag, maybe, when I run Sage?

EDIT: In response to David Coudert's comment, here is the kind of behavior I'm seeing, on a relevant snippet:

sage: def opt(x):
....:     mip = MixedIntegerLinearProgram(maximization=False, solver="GLPK/exact")
....:     mip.add_constraint(mip[0]+mip[1] <= 1)
....:     mip.add_constraint(mip[0]-mip[1] <= 1)
....:     mip.add_constraint(-mip[0]-mip[1] <= 1)
....:     mip.add_constraint(-mip[0]+mip[1] <= 1)
....:     mip.set_objective(mip[0]+x*mip[1])
....:     return mip.solve()
....: 
sage: [opt(n) for n in range(3)]
glp_exact: 4 rows, 2 columns, 8 non-zeros
GNU MP bignum library is being used
*     0:   objval =                      0   (0)
*     2:   objval =                     -1   (0)
OPTIMAL SOLUTION FOUND
glp_exact: 4 rows, 2 columns, 8 non-zeros
GNU MP bignum library is being used
*     0:   objval =                      0   (0)
*     1:   objval =                     -1   (0)
OPTIMAL SOLUTION FOUND
glp_exact: 4 rows, 2 columns, 8 non-zeros
GNU MP bignum library is being used
*     0:   objval =                      0   (0)
*     2:   objval =                     -2   (0)
OPTIMAL SOLUTION FOUND
[-1.0, -1.0, -2.0]

I would only like to have the final line of output printed to the console, yet am also finding the three pieces from GLPK put there too.

EDIT 2: I realized I forgot to mention that I'm running Sage 7.4 and that I may have trouble installing CPLX or Gurobi on the server since I do not have admin privileges there. These appear to be the only solvers which allow for the "logfile" approach.

edit retag flag offensive reopen merge delete

Closed for the following reason the question is answered, right answer was accepted by zjs
close date 2021-09-22 03:30:19.642868

Comments

Can you give a (minimal) example of the kind of code you use ? Also, have you tried to set the log filename p.solver_parameter("logfile", "/path/to/some/logfile.txt") or p.solver_parameter("logfile", "/dev/null") ? it seems that the output you get is what should be in the log file.

David Coudert gravatar imageDavid Coudert ( 2021-09-20 18:20:47 +0200 )edit

@David Coudert, I have added a code snippet and output sample to the main post. Just to be totally certain, changing .solver_parameter will only do so for the GLPK output, yes? Since I am still interested in printing other content to the console.

zjs gravatar imagezjs ( 2021-09-20 19:16:22 +0200 )edit
1

Since you use "GLPK/exact", can you try mip.solver_parameter("verbosity_simplex", "GLP_MSG_OFF").

You can find the list of parameters you can modify at https://doc.sagemath.org/html/en/refe...

I checked the interfaces we other solvers and currently we can only set the log file for cplex and gurobi.

David Coudert gravatar imageDavid Coudert ( 2021-09-21 15:28:08 +0200 )edit

I can not reproduce your issue with Sage 9.5.beta1, i do not have any such noise. Perhaps could you just upgrade your version of Sage.

tmonteil gravatar imagetmonteil ( 2021-09-21 17:00:25 +0200 )edit
1

@David Coudert, thank you very much! The following indeed seems to work (inserted immediately following the declaration of the MixedIntegerLinearProgram):

mip.solver_parameter("simplex_or_intopt", "simplex_only")
mip.solver_parameter("verbosity_simplex", "GLP_MSG_OFF")

@tmonteil I am not sure if I will be able to upgrade Sage on the server because I do not have admin privileges.

zjs gravatar imagezjs ( 2021-09-22 03:25:41 +0200 )edit