problem.getpresolvebasis

Purpose

Returns the current basis from memory into the user's data areas. If the problem is presolved, the presolved basis will be returned. Otherwise the original basis will be returned.

Synopsis

problem.getpresolvebasis(rstatus, cstatus)

Arguments

rstatus

Array of length problem.attributes.rows to the basis status of the stack, surplus or artificial variable associated with each row. The status will be one of:

0	slack, surplus or artificial is non-basic at lower bound;
1	slack, surplus or artificial is basic;
2	slack or surplus is non-basic at upper bound.

May be None if not required.

cstatus

Array of length problem.attributes.cols to hold the basis status of the columns in the constraint matrix. The status will be one of:

0	variable is non-basic at lower bound, or superbasic at zero if the variable has no lower bound;
1	variable is basic;
2	variable is at upper bound;
3	variable is super-basic.

May be None if not required.

Example

The following obtains and outputs basis information on a presolved problem prior to the global search:

cs = []
p = xpress.problem()
p.read("global1", "")
p.mipoptimize()
p.getpresolvebasis(cstatus=cs)

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problem.getpresolvebasis

problem.getpresolvebasis