Purpose
Writes the current
problem to an MPS or LP file.
Synopsis
int XPRS_CC XPRSwriteprob(XPRSprob prob, const char *filename, const char *flags);
WRITEPROB [-flags] [filename]
Arguments
|
prob
|
The current problem.
|
|
filename
|
A string of up to
MAXPROBNAMELENGTH characters to contain the file name to which the problem is to be written. If omitted, the default
problem_name is used with a
.mps extension, unless the
l flag is used in which case the extension is
.lp.
|
|
flags
|
Flags, which can be one or more of the following:
|
o
|
one element per line;
|
|
n
|
output the scaled problem;
|
|
s
|
scrambled vector names;
|
|
l
|
output in LP format;
|
|
p
|
output values in full precision (obsolete as this is now default behavior);
|
|
t
|
omit the Xpress header in LP format;
|
|
v
|
use the provided filename verbatim, without appending the
.mps or
.lp extension;
|
|
z
|
compress the output file.
|
|
Example
The following example outputs the current problem in LP format with scrambled vector names to the file
problem_name
.lp.
XPRSwriteprob(prob, "", "ls");
See also examples
loadlp.c, repair.c, trimloss.c, tsp.c.
Further information
1. If
XPRSloadlp,
XPRSloadmip,
XPRSloadmiqp or
XPRSloadqp is used to obtain a matrix then there is no association between the objective function and the
N rows in the matrix and so a separate
N row (called
__OBJ___) is created when you do an
XPRSwriteprob (
WRITEPROB). Also if you do an
XPRSreadprob (
READPROB) and then change either the objective row or the
N row in the matrix corresponding to the objective row, you lose the association between the two and the
__OBJ___ row is created when you do an
XPRSwriteprob (
WRITEPROB). To remove the objective row from the matrix when doing an
XPRSreadprob (
READPROB), set
KEEPNROWS to
-1 before
XPRSreadprob (
READPROB).
2.
Warning: If
XPRSreadprob (
READPROB) is used to input a problem, then the input file will be overwritten by
XPRSwriteprob (
WRITEPROB) if a new filename is not specified.
3. The Optimizer can write compressed matrix files in the following formats, as long as the command-line tool necessary to compress the file can be located in the path:
bzip2,
xz,
lzma,
Z,
zip,
tar,
tgz. The Optimizer has built-in support for the
gz format: no external tools are necessary to write gzipped matrix files.
Related topics
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