Remove output messages

[Andres Codas]

Hi,

I'm solving a batch of easy problems, and I would like to suppress
all presolve messages and cplex messages output to the console.

How can i do this?

Thanks

Andres

[Paul]

http://bit.ly/ohqflE

You can search this group for other replies -- it's a FAQ.

Paul

[Andres Codas]

Paul,

Thanks for your quick response, in fact I saw that thread before.

Since in the batch of easy problems most of them are infeasible, I'm
using the options:

option presolve_warnings 100000000000000;
option eexit -10000000000;
option solver_msg 0;

And then when solving I do:

solve > solveOutput.txt;

However I can still see the presolve messages like:


suffix dunbdd OUT;
presolve: constraint pressDef cannot hold:
body >= 0 cannot be <= -64.4445; difference = 64.4445
1 presolve messages suppressed.
2 presolve messages suppressed.
1 presolve messages suppressed.
1 presolve messages suppressed.
1 presolve messages suppressed.
1 presolve messages suppressed.
3 presolve messages suppressed.
2 presolve messages suppressed.
2 presolve messages suppressed.
9 presolve messages suppressed.
2 presolve messages suppressed.
Setting $presolve_eps >= 1.4e-10 might help.
2 presolve messages suppressed.
Setting $presolve_eps >= 1.4e-10 might help.
4 presolve messages suppressed.

Is it possible to remove these messages?

Thanks again

Andres

[Paul]

I'm not positive, but I don't think so.  CPLEX is a chatty little bugger, and even if you redirect stdout to /dev/null or a log file, I think it writes some status messages to stderr (and hence to the screen).  I think it should be possible to redirect stderr to stdout in the command line that runs AMPL (exactly how is probably operating system dependent); doing that and redirecting output to a file in the solve command (which temporarily reroutes stdout) might work, but I've never tried it.

Paul

[Robert Fourer]

All of the presolve output, including the summaries of messages suppressed,
should be suppressed by setting "option presolve_warnings -1". (This is
reported in www.netlib.org/ampl/changes but is not mentioned in the AMPL
book.)

We are checking into why "suffix dunbdd OUT;" appears even when the solve
output is redirected. However if you do not have need for the values in the
dual unboundedness ray (which are given by appending the suffix .dunbdd)
then you can suppress this message by adding 'rays 0' to the cplex_options
string. In any case this message will appear only once per run.

Bob Fourer
4...@ampl.com

[AMPL Optimization]

A better way to suppress the "suffix dunbdd OUT;" message is to declare 

     suffix dunbdd;

or

      suffix dunbdd OUT; 

once in your script, before the first "solve;" where the suffix might be relevant.  Then the solver doesn't have to create this suffix and won't issue the unwanted message saying that it has been created.  This works whether or not your script actually uses the dual ray.