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<p>I don't have a copy of an MPSX manual to hand. Can someone who has an MPSX manual check this out? OSL behaves in the same way as Clp, and I am sure that would have conformed to MPSX standards.<br>
<br>
Thanks<br>
<br>
John Forrest<br>
<br>
<img width="16" height="16" src="cid:1__=0ABBFFCCDFA5D20F8f9e8a93df938@us.ibm.com" border="0" alt="Inactive hide details for "William H. Patton" ---02/15/2009 10:45:04 AM---CLP interprets a constant in the objective with the o"><font color="#424282">"William H. Patton" ---02/15/2009 10:45:04 AM---CLP interprets a constant in the objective with the opposite sign compared</font><br>
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<font size="2" color="#5F5F5F">From:</font></td><td width="100%"><img width="1" height="1" src="cid:2__=0ABBFFCCDFA5D20F8f9e8a93df938@us.ibm.com" border="0" alt=""><br>
<font size="2">"William H. Patton" <pattonwh@comcast.net></font></td></tr>
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<font size="2" color="#5F5F5F">To:</font></td><td width="100%"><img width="1" height="1" src="cid:2__=0ABBFFCCDFA5D20F8f9e8a93df938@us.ibm.com" border="0" alt=""><br>
<font size="2"><clp@list.coin-or.org></font></td></tr>
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<font size="2" color="#5F5F5F">Date:</font></td><td width="100%"><img width="1" height="1" src="cid:2__=0ABBFFCCDFA5D20F8f9e8a93df938@us.ibm.com" border="0" alt=""><br>
<font size="2">02/15/2009 10:45 AM</font></td></tr>
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<font size="2" color="#5F5F5F">Subject:</font></td><td width="100%"><img width="1" height="1" src="cid:2__=0ABBFFCCDFA5D20F8f9e8a93df938@us.ibm.com" border="0" alt=""><br>
<font size="2">[Clp] constant in MPS objective</font></td></tr>
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<tt><br>
CLP interprets a constant in the objective with the opposite sign compared<br>
to lp_solve and glpsol. I think they got it right.<br>
<br>
NAME ex1c <br>
ROWS<br>
N OBJROW<br>
L C1<br>
L R2<br>
COLUMNS<br>
x1 OBJROW 1. C1 2. <br>
x1 R2 -4. <br>
x2 OBJROW -2. C1 1. <br>
x2 R2 4. <br>
RHS<br>
RHS OBJROW +10. C1 5.<br>
RHS R2 5. <br>
ENDATA<br>
<br>
Or <br>
<br>
NAME ex1b <br>
ROWS<br>
N OBJROW<br>
L C1<br>
L R2<br>
COLUMNS<br>
x1 OBJROW 1. C1 2. <br>
x1 R2 -4. <br>
x2 OBJROW -2. C1 1. <br>
x2 R2 4. <br>
RHS<br>
RHS OBJROW -10. C1 5. <br>
RHS R2 5. <br>
ENDATA<br>
<br>
Solve oppositely to lp_solve<br>
Clp:import ex1b.MPS<br>
At line 1 NAME ex1b<br>
At line 2 ROWS<br>
At line 6 COLUMNS<br>
At line 11 RHS<br>
At line 14 ENDATA<br>
Problem ex1b has 2 rows, 2 columns and 4 elements<br>
Model was imported from .\ex1b.MPS in 0 seconds<br>
Clp:solve<br>
0 Obj 10 Dual inf 2 (1)<br>
2 Obj 6.25<br>
Optimal - objective value 6.25<br>
Optimal objective 6.25 - 2 iterations time 0.002<br>
Clp:<br>
Clp:import ex1c.MPS<br>
At line 1 NAME ex1c<br>
At line 2 ROWS<br>
At line 6 COLUMNS<br>
At line 11 RHS<br>
At line 14 ENDATA<br>
Problem ex1c has 2 rows, 2 columns and 4 elements<br>
Model was imported from .\ex1c.MPS in 0 seconds<br>
Clp:solve<br>
0 Obj -10 Dual inf 2 (1)<br>
2 Obj -13.75<br>
Optimal - objective value -13.75<br>
Optimal objective -13.75 - 2 iterations time 0.002<br>
Clp:<br>
<br>
==============================================<br>
\Jun>lp_solve -mps ex1b.mps<br>
<br>
Value of objective function: -13.75000000<br>
<br>
Actual values of the variables:<br>
x1 1.25<br>
x2 2.5<br>
<br>
\Jun>lp_solve -mps ex1c.mps<br>
<br>
Value of objective function: 6.25000000<br>
<br>
Actual values of the variables:<br>
x1 1.25<br>
x2 2.5<br>
<br>
\Jun><br>
<br>
==============================================<br>
\glpk\glpk-4.8>glpsol ex1b.mps<br>
lpx_read_mps: reading problem data from `ex1b.mps'...<br>
lpx_read_mps: problem ex1b<br>
lpx_read_mps: 3 rows, 2 columns, 6 non-zeros<br>
lpx_read_mps: 14 cards were read<br>
lpx_simplex: original LP has 3 rows, 2 columns, 6 non-zeros<br>
lpx_simplex: presolved LP has 2 rows, 2 columns, 4 non-zeros<br>
lpx_adv_basis: size of triangular part = 2<br>
* 0: objval = -1.000000000e+001 infeas = 0.000000000e+000 (0)<br>
* 2: objval = -1.375000000e+001 infeas = 0.000000000e+000 (0)<br>
OPTIMAL SOLUTION FOUND<br>
Time used: 0.0 secs<br>
Memory used: 0.1M (91756 bytes)<br>
<br>
\glpk\glpk-4.8><br>
\glpk\glpk-4.8>glpsol ex1c.mps<br>
lpx_read_mps: reading problem data from `ex1c.mps'...<br>
lpx_read_mps: problem ex1c<br>
lpx_read_mps: 3 rows, 2 columns, 6 non-zeros<br>
lpx_read_mps: 14 cards were read<br>
lpx_simplex: original LP has 3 rows, 2 columns, 6 non-zeros<br>
lpx_simplex: presolved LP has 2 rows, 2 columns, 4 non-zeros<br>
lpx_adv_basis: size of triangular part = 2<br>
* 0: objval = 1.000000000e+001 infeas = 0.000000000e+000 (0)<br>
* 2: objval = 6.250000000e+000 infeas = 0.000000000e+000 (0)<br>
OPTIMAL SOLUTION FOUND<br>
Time used: 0.0 secs<br>
Memory used: 0.1M (91756 bytes)<br>
<br>
\glpk\glpk-4.8><br>
<br>
William<br>
<br>
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