problem.getprimalray

Purpose

Retrieves a primal ray (primal unbounded direction) for the current problem, if the problem is found to be unbounded.

Synopsis

problem.getprimalray(ray)

Argument

ray	Array of length problem.attributes.cols to hold the ray. May be None if not required.

Example

The following code tries to retrieve a primal ray:

if not p.hasprimalray():
    print("Could not retrieve a primal ray")
else:
    ray = []
    p.getprimalray(ray)
    print("primal ray:", ray)

Further information

1. It is possible to retrieve a primal ray only when, after solving an LP problem, the final status ( LPSTATUS) is xpress.lp_unbounded.

2. Primal rays are not post-solved. If the problem is in a presolved state, the primal ray that is returned will be for the presolved problem. If the problem was solved with presolve on and has been restored to the original state (the default behavior), this function will not be able to return a ray. To ensure that a primal ray can be obtained, it is recommended to solve a problem with presolve turned off ( PRESOLVE = 0).

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problem.getprimalray

problem.getprimalray