Using a gurobi.env file
When you want to change the values of Gurobi parameters, you actually
have several options available for doing so. We've already discussed
parameter changes through the command-line tool (e.g.,
gurobi_cl Threads=1 coins.lp), and through interactive shell
commands (e.g., m.setParam('Threads', 1)). Each of our
language APIs also provides methods for setting parameters. The other
option we'd like to mention now is the gurobi.env file.
Whenever the Gurobi library starts, it will look for file
gurobi.env in the current working directory, and will apply any
parameter changes contained therein. This is true whether the Gurobi
library is invoked from the command-line, from the interactive shell,
or from any of the Gurobi APIs. Parameter settings are stored one per
line in this file, with the parameter name first, followed by at least
one space, followed by the desired value. Lines beginning with the
# sign are comments and are ignored. To give an example, the
following (Linux) commands:
echo "Threads 1" > gurobi.env gurobi_cl coins.lpwould read the new value of the
Threads parameter from file
gurobi.env and then optimize model coins.lp using
one thread. Note that if the same parameter is changed in both gurobi.env and in your program (or through the Gurobi
command-line), the value from gurobi.env will be overridden.
The distribution includes a sample gurobi.env file (in the
bin directory). The sample includes every parameter, with the
default value for each, but with all settings commented out.
