XPRSgetmqobj

[Previous] [Next]

XPRSgetmqobj

Purpose

Returns the nonzeros in the quadratic objective coefficients matrix for the columns in a given range. To achieve maximum efficiency, XPRSgetmqobj returns the lower triangular part of this matrix only.

Synopsis

int XPRS_CC XPRSgetmqobj (XPRSprob prob, int mstart[], int mclind[], double dobjval[], int size, int *nels, int first, int last);

Arguments

prob

The current problem.

mstart

Integer array which will be filled with indices indicating the starting offsets in the mclind and dobjval arrays for each requested column. It must be length of at least last-first+2. Column i starts at position mstart[i] in the mrwind and dmatval arrays, and has mstart[i+1]-mstart[i] elements in it. May be NULL if if size is 0.

mclind

Integer array of length size which will be filled with the column indices of the nonzero elements in the lower triangular part of Q. May be NULL if size is 0.

dobjval

Double array of length size which will be filled with the nonzero element values. May be NULL if size is 0.

size

Double array of length size containing the objective function coefficients.

nels

Pointer to the integer where the number of nonzero elements in the mclind and dobjval arrays will be returned. If the number of nonzero elements is greater than size, then only size elements will be returned. If nels is smaller than size, then only nels will be returned.

first

First column in the range.

last

Last column in the range.

Further information

1. The objective function is of the form c'x+0.5x'Qx where Q is positive semi-definite for minimization problems and negative semi-definite for maximization problems. If this is not the case the optimization algorithms may converge to a local optimum or may not converge at all. Note that only the upper or lower triangular part of the Q matrix is returned.

2. The row and column indices follow the usual C convention of going from 0 to nrow-1 and 0 to ncol-1 respectively.

3. The double constants XPRS_PLUSINFINITY and XPRS_MINUSINFINITY are defined in the Optimizer library header file.

Related topics

XPRSchgmqobj, XPRSchgqobj, XPRSgetqobj.

[Previous] [Next] [Index]

If you have any comments or suggestions about these pages, please send mail to docs@dashoptimization.com.

prob	The current problem.
mstart	Integer array which will be filled with indices indicating the starting offsets in the mclind and dobjval arrays for each requested column. It must be length of at least last-first+2. Column i starts at position mstart[i] in the mrwind and dmatval arrays, and has mstart[i+1]-mstart[i] elements in it. May be NULL if if size is 0.
mclind	Integer array of length size which will be filled with the column indices of the nonzero elements in the lower triangular part of Q. May be NULL if size is 0.
dobjval	Double array of length size which will be filled with the nonzero element values. May be NULL if size is 0.
size	Double array of length size containing the objective function coefficients.
nels	Pointer to the integer where the number of nonzero elements in the mclind and dobjval arrays will be returned. If the number of nonzero elements is greater than size, then only size elements will be returned. If nels is smaller than size, then only nels will be returned.
first	First column in the range.
last	Last column in the range.