CPXXgetcols and CPXgetcols

The routine CPXXgetcols/CPXgetcols accesses a range of columns of the constraint matrix of a CPLEX problem object.

int CPXXgetcols( CPXCENVptr env, CPXCLPptr lp, CPXNNZ * nzcnt_p, CPXNNZ * cmatbeg, CPXDIM * cmatind, double * cmatval, CPXNNZ cmatspace, CPXNNZ * surplus_p, CPXDIM begin, CPXDIM end )

int CPXgetcols( CPXCENVptr env, CPXCLPptr lp, int * nzcnt_p, int * cmatbeg, int * cmatind, double * cmatval, int cmatspace, int * surplus_p, int begin, int end )

Description

The routine CPXXgetcols/CPXgetcols accesses a range of columns of the constraint matrix of a CPLEX problem object. 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.

Note: If the value of cmatspace is zero, the negative of the value of surplus_p returned specifies the length needed for the arrays cmatind and cmatval.

Arguments

env: A pointer to the CPLEX environment as returned by CPXXopenCPLEX/CPXopenCPLEX.
lp: A pointer to a CPLEX problem object as returned by CPXXcreateprob/CPXcreateprob.
nzcnt_p: A pointer to an integer to contain the number of nonzeros returned; that is, the true length of the arrays cmatind and cmatval. If the function returns either 0 (zero) or CPXERR_NEGATIVE_SURPLUS, then this value contains the number of elements that were stored in cmatind or cmatval. Otherwise, the value is either unchanged or set to 0 (zero).
cmatbeg: An array to contain indices specifying where each of the requested columns begins in the arrays cmatval and cmatind. Specifically, column j consists of the entries in cmatval and cmatind in the range from cmatbeg[j-begin] to cmatbeg[(j+1)-begin]-1. (Column end consists of the entries from cmatbeg[end-begin] to nzcnt_p-1.) This array must be of length at least (end-begin+1).
cmatind: An array to contain the row indices associated with the elements of cmatval. May be NULL if cmatspace is zero.
cmatval: An array to contain the nonzero coefficients of the specified columns. May be NULL if cmatspace is zero.
cmatspace: An integer specifying the length of the arrays cmatind and cmatval. 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 cmatind and cmatval. A nonnegative value of surplus_p specifies that the length of the arrays was sufficient. A negative value specifies that the length was insufficient and that the routine could not complete its task. In this case, CPXXgetcols/CPXgetcols returns the value CPXERR_NEGATIVE_SURPLUS, and the negative value of surplus_p specifies the amount of insufficient space in the arrays.
begin: An integer specifying the beginning of the range of columns to be returned.
end: An integer specifying the end of the range of columns to be returned.

Return

The routine returns 0 (zero) if successful and nonzero if an error occurs. The value CPXERR_NEGATIVE_SURPLUS specifies that insufficient space was available in the arrays cmatind and cmatval to hold the nonzero coefficients.

Example


status = CPXgetcols (env, lp, &nzcnt, cmatbeg, cmatind,
	      cmatval, cmatspace, &surplus, 0,
	      cur_numcols-1);