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CPXgetquad

int CPXPUBLIC CPXgetquad(CPXCENVptr env, CPXCLPptr lp, int * nzcnt_p, int * qmatbeg, int * qmatind, double * qmatval, int qmatspace, int * surplus_p, int begin, int end)
Definition file: cplex.h
Include files: cplex.h

The routine CPXgetquad is used to access a range of columns of the matrix Q of a model with a quadratic objective function. The beginning and end of the range, along with the length of the arrays in which the nonzero entries of these columns are to be returned, must be specified.

Specifically, column j consists of the entries in qmatval and qmatind in the range from qmatbeg[j - begin] to qmatbeg[(j + 1) - begin]-1. (Column end consists of the entries from qmatbeg[end - begin] to nzcnt_p-1.) This array must be of length at least (end - begin+ 1).

A nonnegative value of surplus_p indicates that the length of the arrays was sufficient. A negative value indicates that the length was insufficient and that the routine could not complete its task. In this case, CPXgetquad returns the value CPXERR_NEGATIVE_SURPLUS, and the negative value of surplus_p indicates the amount of insufficient space in the arrays.

Note
If the value of qmatspace is zero, the negative of the value of surplus_p returned indicates the length needed for the arrays qmatind and qmatval.

Example

 status = CPXgetquad (env, lp, &nzcnt, qmatbeg, qmatind,
                      qmatval, cmatspace, &surplus, 0,
                      cur_numquad-1);

Parameters:

env

A pointer to the CPLEX environment as returned by CPXopenCPLEX.

lp

A pointer to a CPLEX problem object as returned by CPXcreateprob.

nzcnt_p

A pointer to an integer to contain the number of nonzeros returned; that is, the true length of the arrays qmatind and qmatval.

qmatbeg

An array to contain indices indicating where each of the requested columns of Q begins in the arrays qmatval and qmatind.

qmatind

An array to contain the row indices associated with the elements of qmatval. May be NULL if cmatspace is zero.

qmatval

An array to contain the nonzero coefficients of the specified columns. May be NULL if cmatspace is zero.

qmatspace

An integer indicating the length of the arrays qmatind and qmatval. May be zero.

surplus_p

A pointer to an integer to contain the difference between cmatspace and the number of entries in each of the arrays qmatind and qmatval.

begin

An integer indicating the beginning of the range of columns to be returned.

end

An integer indicating the end of the range of columns to be returned.

Returns:

The routine returns zero on success and nonzero if an error occurs.