Initializing help system before first use

XPRSaddcols, XPRSaddcols64

Purpose
Allows columns to be added to the matrix after passing it to the Optimizer using the input routines.
Synopsis
int XPRS_CC XPRSaddcols(XPRSprob prob, int ncols, int ncoefs, const double objcoef[], const int start[], const int rowind[], const double rowcoef[], const double lb[], const double ub[]);

int XPRS_CC XPRSaddcols64(XPRSprob prob, int ncols, XPRSint64 ncoefs, const double objcoef[], const XPRSint64 start[], const int rowind[], const double rowcoef[], const double lb[], const double ub[]);
Arguments
prob 
The current problem.
ncols 
Number of new columns.
ncoefs 
Number of new nonzeros in the added columns.
objcoef 
Double array of length ncols containing the objective function coefficients of the new columns.
start 
Integer array of length ncols containing the offsets in the rowind and rowcoef arrays of the start of the elements for each column.
rowind 
Integer array of length ncoefs containing the row indices for the elements in each column.
rowcoef 
Double array of length ncoefs containing the element values.
lb 
Double array of length ncols containing the lower bounds on the added columns.
ub 
Double array of length ncols containing the upper bounds on the added columns.
Related controls
Integer
EXTRACOLS 
Number of extra columns to be allowed for.
EXTRAELEMS 
Number of extra matrix elements to be allowed for.
EXTRAMIPENTS 
Number of extra global entities to be allowed for.

Double
MATRIXTOL 
Tolerance on matrix elements.

Example
In this example, we consider the two problems:

(a) maximize: 2x + y    (b) maximize: 2x + y + 3z
subject to: x + 4y ≤ 24    subject to: x + 4y + 2z ≤ 24
y ≤ 5    y + z ≤ 5
3x + y ≤ 20    3x + y ≤ 20
x + y ≤ 9    x + y + 3z ≤ 9
   z ≤ 12


Using XPRSaddcols, the following transforms (a) into (b) and then names the new variable using XPRSaddnames: 
obj[0] = 3;
start[] = {0};
rowind[] = {0, 1, 3};
matval[] = {2.0, 1.0, 3.0};
lb[0] = XPRS_MINUSINFINITY; ub[0] = 12.0;
...
XPRSaddcols(prob,1,3,obj,start,rowind,matval,lb,ub);
XPRSaddnames(prob,2,"z",2,2);
Further information
1. The double constants XPRS_PLUSINFINITY and XPRS_MINUSINFINITY defined in the library header file can be used to represent plus and minus infinity respectively in the bound arrays.
2. If the columns are added to a MIP problem then they will be continuous variables. Use XPRSchgcoltype to impose integrality conditions on such new columns.
Related topics
XPRSaddnames, XPRSaddrows, XPRSdelcols, XPRSchgcoltype.

Parent Topic Console and Library Functions

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