Initializing help system before first use

XPRSwriteprob (WRITEPROB)

Purpose
Writes the current problem to an MPS or LP file.
Topic area
File IO
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 or MPS 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 els_managedcuts.c, els_usercuts.c, 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
XPRSreadprob ( READPROB).

Parent Topic Layout for Function Descriptions

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