Putclose

The Putclose keyword is used to close a file during the execution of program.  Otherwise GAMS automatically closes files when it exits.

Example:

One application where this is useful involves writing an option file that controls a solver from within a GAMS model.  In that case, the file must be closed prior to the SOLVE statement and Putclose allows that to be done.  The following example shows the creation and closing of an option file for the MINOS solver as implemented in frstpart.gms.

FILE  OPT   MINOS option file  / MINOS5.OPT /;

Put OPT;

Put 'BEGIN'/

    '  Iteration limit        500'/

    '  Major damping parameter 0.5'/

    '  Feasibility tolerance   1.0E-7'/

    '  Scale all variables'/

    'END';

Putclose OPT;

One may also wish to report what loop one is on in a large model using commands like (comparw.gms)

$set console

$if %system.filesys% == UNIX  $set console /dev/tty

$if %system.filesys% == DOS $set console con

$if %system.filesys% == MS95  $set console con

$if %system.filesys% == MSNT  $set console con

$if "%console%." == "." abort "filesys not recognized";

file screen / '%console%' /;

followed by

loop(scenarios,

    put screen;

    put 'I am on scenario ' Scenarios.tl;

    putclose;

that writes to the screen (or DOS window that must be made visible in the IDE using file options execute).  In this case Putclose is necessary to cause the line to become visible.  One can also use Putclose to change the title of the DOS box.

Notes: