GAMS — The Solver Manuals - Available Software

84 COIN-OR
# This is a comment
# Turn off the NLP scaling
nlp_scaling_method none
# Change the initial barrier parameter
mu_init 1e-2
# Set the max number of iterations
max_iter 500
is a valid ipopt.opt file.
Note, that GAMS/CoinIpopt overwrites the Ipopt default setting for the parameters bound relax factor (set to
0.0) and mu strategy (set to adaptive). You can change these values by specifying these options in your Ipopt
options file.
GAMS/CoinIpopt understand currently the following GAMS parameters: reslim (time limit), iterlim (iteration
limit), domlim (domain violation limit). You can set them either on the command line, e.g. iterlim=500, or
inside your GAMS program, e.g. Option iterlim=500;.
5.6 Detailed Description of CoinIpopt Options
Output
print level: Output verbosity level.
Sets the default verbosity level for console output. The larger this value the more detailed is the output. The
valid range for this integer option is −2 ≤ print level ≤ 12 and its default value is 5.
file print level: Verbosity level for output file.
NOTE: This option only works when read from the ipopt.opt options file! Determines the verbosity level for the
file specified by ”output file”. By default it is the same as ”print level”. The valid range for this integer option
is 0 ≤ file print level ≤ 12 and its default value is 5.
output file: File name of desired output file (leave unset for no file output).
NOTE: This option only works when read from the ipopt.opt options file! An output file with this name will be
written (leave unset for no file output). The verbosity level is by default set to ”print level”, but can be overridden
with ”file print level”. The file name is changed to use only small letters. The default value for this string option
is ””.
Possible value is any acceptable standard file name.
print info string: Enables printing of additional info string at end of iteration output.
This string contains some insider information about the current iteration. The default value for this string option
is ”no”.
Possible values:
• no: don’t print string
• yes: print string at end of each iteration output
print options documentation: Switch to print all algorithmic options.
If selected, the algorithm will print the list of all available algorithmic options with some documentation before
solving the optimization problem. The default value for this string option is ”no”.
Possible values: