XPRSaddcols, XPRSaddcols64
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 newcol, int newnz, const double objx[], const int mstart[], const int mrwind[], const double dmatval[], const double bdl[], const double bdu[]);
int XPRS_CC XPRSaddcols64(XPRSprob prob, int newcol, XPRSint64 newnz, const double objx[], const XPRSint64 mstart[], const int mrwind[], const double dmatval[], const double bdl[], const double bdu[]);
Arguments
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prob
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The current problem.
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newcol
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Number of new columns.
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newnz
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Number of new nonzeros in the added columns.
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objx
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Double array of length
newcol containing the objective function coefficients of the new columns.
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mstart
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Integer array of length
newcol containing the offsets in the
mrwind and
dmatval arrays of the start of the elements for each column.
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mrwind
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Integer array of length
newnz containing the row indices for the elements in each column.
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dmatval
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Double array of length
newnz containing the element values.
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bdl
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Double array of length
newcol containing the lower bounds on the added columns.
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bdu
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Double array of length
newcol containing the upper bounds on the added columns.
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Related controls
Integer
Double
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Number of extra columns to be allowed for.
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Number of extra matrix elements to be allowed for.
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Number of extra global entities to be allowed for.
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Double
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Tolerance on matrix elements.
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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;
mstart[] = {0};
mrwind[] = {0, 1, 3};
matval[] = {2.0, 1.0, 3};
bdl[0] = XPRS_MINUSINFINITY; bdu[0] = 12;
...
XPRSaddcols(prob,1,3,obj,mstart,mrwind,matval,bdl,bdu);
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
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