Column Names lost in Write_MPS output

[joerg_strebel]

Hello!

I've been reading this column for quite a while, and now, I have a puzzling problem:
I usually build my models using the java library and after having added the constraint and the objective function, I use set_col_name() to uniquely name my variables.
Afterwards, I let lp_solve write the lp model to both an LP file and an MPS file (using write_lp(), write_mps()). However, the column names are only present in the lp file, but not in the mps file; there the variables are named Cxxxx (x = arbitrary number).
I set presolve parameters, and I write the model before I call solve().
I use lp_solve 5.5.0.14, WindowsXP.

What could be the reason for the missing column names in the mps file?

Thank you!

Best regards

Jörg Strebel

[William H. Patton]

This seems strange. I just checked in the IDE and at the default I get funny
8 column names ok.

Rows that did not have names become Rnnn….

 

So check your code for

http://lpsolve.sourceforge.net/5.5/set_use_names.htm

Maybe you need  to force TRUE,TRUE args.

 

  _____  

From: lp_solve@... [mailto:lp_solve@...] On Behalf
Of joerg_strebel
Sent: Tuesday, September 22, 2009 10:16 AM
To: lp_solve@...
Subject: [lp_solve] Column Names lost in Write_MPS output

 

 

Hello!

I've been reading this column for quite a while, and now, I have a puzzling
problem:
I usually build my models using the java library and after having added the
constraint and the objective function, I use set_col_name() to uniquely name
my variables.
Afterwards, I let lp_solve write the lp model to both an LP file and an MPS
file (using write_lp(), write_mps()). However, the column names are only
present in the lp file, but not in the mps file; there the variables are
named Cxxxx (x = arbitrary number).
I set presolve parameters, and I write the model before I call solve().
I use lp_solve 5.5.0.14, WindowsXP.

What could be the reason for the missing column names in the mps file?

Thank you!

Best regards

Jörg Strebel

[peter_notebaert]

Could it be that these names are longer than 8 characters? The standard MPS format only allows a length of 8 for variable and constraint names. The MPS writer will use Rx and Cx if the name is longer.
To solve this, you can use the free MPS format.

Peter


From: William H. Patton
Sent: Tuesday, September 29, 2009 06:37
To: lp_solve@...
Subject: RE: [lp_solve] Column Names lost in Write_MPS output


 
This seems strange. I just checked in the IDE and at the default I get funny 8 column names ok.

Rows that did not have names become Rnnn..



So check your code for

http://lpsolve.sourceforge.net/5.5/set_use_names.htm

Maybe you need  to force TRUE,TRUE args.




--------------------------------------------------------------------------------

From: lp_solve@... [mailto:lp_solve@...] On Behalf Of joerg_strebel
Sent: Tuesday, September 22, 2009 10:16 AM
To: lp_solve@...
Subject: [lp_solve] Column Names lost in Write_MPS output



 

Hello!

I've been reading this column for quite a while, and now, I have a puzzling problem:
I usually build my models using the java library and after having added the constraint and the objective function, I use set_col_name() to uniquely name my variables.
Afterwards, I let lp_solve write the lp model to both an LP file and an MPS file (using write_lp(), write_mps()). However, the column names are only present in the lp file, but not in the mps file; there the variables are named Cxxxx (x = arbitrary number).
I set presolve parameters, and I write the model before I call solve().
I use lp_solve 5.5.0.14, WindowsXP.

What could be the reason for the missing column names in the mps file?

Thank you!

Best regards

Jörg Strebel