int GRBBinvColj ( GRBmodel *model,
    int j,
    GRBsvec *x )

Computes the solution to the linear system $Bx=A_j$, where $B$ is the current simplex basis matrix and $A_j$ is the column of the constraint matrix $A$ associated with variable $j$.

Return value:

A non-zero return value indicates that a problem occurred while computing the desired vector. Refer to the Error Code table for a list of possible return values. Details on the error can be obtained by calling GRBgeterrormsg.


model: The model. Note that the model must have a current optimal basis, as computed by GRBoptimize.

j: Indicates the index of the column of $A$ to use as the right-hand side for the linear solve. The index j must be between 0 and cols-1, where cols is the number of columns in the model.

x: The sparse result vector. The user is responsible for allocating the ind and val fields to be large enough to hold as many as one non-zero entry per constraint in the model.