Initializing help system before first use

xpress.init

Purpose
Initializes the Xpress environment prior to creating or reading a problem.
Note that it is not necessary to call this function after importing the Xpress module and before creating or solving a problem, since the environment will be automatically initialized when it is needed for the first time. However, you may want to call xpress.init in a with statement, which allows you to:
  • detect initialization errors (which will be raised as an xpress.ModelError);
  • specify the path to your license file;
  • explicitly acquire the Xpress license;
  • automatically release the Xpress license at the end of the with statement.

Synopsis
xpress.init(lic_path=None)
Argument
lic_path 
(optional) Path to the Xpress license file.
Example
The following example shows how to call xpress.init and why it could be useful: 
try:
  with xp.init():     # Acquire the Xpress license
    p = xp.problem()  # This would imply a call to xp.init() if it had not already been called
    x = p.addVariable()
    y = p.addVariable()
    p.addConstraint(x+y <= 1)
    p.setObjective(x+2*y, sense=xp.maximize)
    p.optimize()
  # Xpress license is implicitly released here
catch xp.ModelError:
  print('Failed to initialize Xpress')
Further information
xpress.init may emit a xpress.LicenseWarning if the path to the license file is not explicitly indicated with the lic_path argument or the XPAUTH_PATH environment variable. This warning can be suppressed by adding the following code before the call to xpress.init: 
import warnings
warnings.simplefilter('ignore', xpress.LicenseWarning)

Related topics
xpress.free

Parent Topic Xpress base functions

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