Index of /geminiatari/FILES/MATH/LPSOLVEB

 Name                    Last modified       Size  Description

 Parent Directory        24-Sep-2006 15:34      -  
 LP_SOLVE.1              28-Jul-1993 07:13     4k  
 LP_SOLVE.MAN            28-Jul-1993 07:13     5k  
 LP_SOLVE.TTP            28-Jul-1993 07:13    53k  

CONTENTS:

This package contains the ANSI C sources for a very efficient (mixed integer)
linear problem solver. To compile without warnings, you need ANSI include
files as well. Its base is a sparse matrix dual simplex LP solver.  MILP
problems are solved with a branch-and-bound iteration over LP solutions.

It uses a lex and yacc parser to read a human-friendly algebraic input format.

The author has used the program to solve LP problems up to about 30000
variables and 50000 constraints (on a 22 MFLOPS HP9000/750).


VECTOR PROCESSORS:

For alliant users, there are pragmas in dual.c which allow to compile it in
vector mode. This reduces the cpu usage with 40% on a FX/8. Do not compile any
of the other files with vector optimization; this will just slow things down.
It should easily be possible to use vector capabilities of other computers.


KNOWN BUGS / PROBLEMS

The program does not store simple bounds on variables in the main matrix.
Therefore, simple problems like:

x + y;
x < 1;
y < 1;

define an empty matrix. This sometimes causes the program to crash. All
real-life problems do not have this property, fortunately.

FUTURE ENHANCEMENTS:

The program lacks two things:

- matrix optimization as preprocessing
- matrix normalization to increase numerical stability

Contributions are welcome.


AUTHOR:

For any comment on the sources, contact: michel@es.ele.tue.nl



INSTALL:

Look into file INSTALL for installation hints.


TESTING:

After a succesful build, run:

lp_solve < ex[12345].lp

The results should be close to (floating point accuracy is important) the
results in  ex[12345].out.