XPRSalter (ALTER)
XPRSalter |
ALTER |
Purpose
Synopsis
int XPRS_CC XPRSalter(XPRSprob prob, const char *filename);
ALTER [filename]
Arguments
|
prob
|
The current problem.
|
|
filename
|
A string of up to
MAXPROBNAMELENGTH characters specifying the file to be read. If omitted, the default
problem_name is used with a
.alt extension.
|
Related controls
Integer
Double
|
Number of extra matrix elements to be allowed for.
|
Double
|
Tolerance on matrix elements.
|
Example 1 (Library)
Since the following call does not specify a filename, the file
problem_name
.alt is read in, from which commands are taken to alter the current matrix.
XPRSalter(prob,"");
Example 2 (Console)
The following example reads in the file
fred.alt, from which instructions are taken to alter the current matrix:
ALTER fred
Further information
1. The file
filename.alt is read. It is an ASCII file containing matrix revision statements in the format described in Section
The Matrix Alteration (.alt) File. The
MODIFY format of the MPS
REVISE data is also supported.
2. It is not possible to alter a problem that is in a presolved state. Call
XPRSpostsolve to bring the problem back to its original state.
3. If the problem was read from an .lp file, the name to use for the right-hand side is the one given by the attribute
RHSNAME which by default is set to
RHS00001.
Related topics
Section
The Matrix Alteration (.alt) File.