<font size=2 face="sans-serif">Thank you, Stefan and John, for the svn
URL for the trunk sources.</font>
<br>
<br><font size=2 face="sans-serif">The good news: I built Cbc successfully,
and using -extraVariables, the new executable was able to solve that troublesome
problem in less than 5 CPU seconds. The trick of aggregating variables
with identical costs is very, very effective on our typical problems.</font>
<br>
<br><font size=2 face="sans-serif">The bad news is that -extraVariables
does not seem to play well with -threads. Perhaps we will not need
-threads, if -extraVariables helps us so much, but I figured you would
want to see the result, so I've appended a log below. It finds a
preliminary solution with DiveCoefficient, then works all its root cuts,
but then it segfaults instantly.</font>
<br>
<br><font size=2 face="sans-serif">We will be excitedly playing with -extraVariables,
and if it works as well as it promises to on our usual problems, we won't
miss multithreading for a while, so the priority on this is quite low.
Thank you, John, for the spectacular improvement (something like
8 orders of magnitude on this problem)!</font>
<br>
<br><font size=2 face="sans-serif">Allan Wechsler</font>
<br><font size=2 face="sans-serif">(Cbc log below.)</font>
<br>
<br><font size=2 face="sans-serif">[acw@ARVON coin-Cbc]$ bin/cbc ../last-problem.mps
-extrav 8 -threads 104 -solve</font>
<br><font size=2 face="sans-serif">Welcome to the CBC MILP Solver </font>
<br><font size=2 face="sans-serif">Version: Trunk (unstable) </font>
<br><font size=2 face="sans-serif">Build Date: Mar 20 2013 </font>
<br><font size=2 face="sans-serif">Revision Number: 1876 </font>
<br>
<br><font size=2 face="sans-serif">command line - bin/cbc ../last-problem.mps
-extrav 8 -threads 104 -solve (default strategy 1)</font>
<br><font size=2 face="sans-serif">At line 1 NAME
BLANK</font>
<br><font size=2 face="sans-serif">At line 2 ROWS</font>
<br><font size=2 face="sans-serif">At line 1694 COLUMNS</font>
<br><font size=2 face="sans-serif">At line 7264 RHS</font>
<br><font size=2 face="sans-serif">At line 7664 BOUNDS</font>
<br><font size=2 face="sans-serif">At line 7883 ENDATA</font>
<br><font size=2 face="sans-serif">Problem BLANK has 1690 rows, 218 columns
and 10834 elements</font>
<br><font size=2 face="sans-serif">Coin0008I BLANK read with 0 errors</font>
<br><font size=2 face="sans-serif">extraVariables was changed from 0 to
8</font>
<br><font size=2 face="sans-serif">threads was changed from 0 to 104</font>
<br><font size=2 face="sans-serif">Continuous objective value is 496912
- 0.01 seconds</font>
<br><font size=2 face="sans-serif">Cgl0003I 0 fixed, 35 tightened bounds,
2 strengthened rows, 0 substitutions</font>
<br><font size=2 face="sans-serif">Cgl0004I processed model has 346 rows,
218 columns (218 integer) and 2983 elements</font>
<br><font size=2 face="sans-serif">Problem has 218 integers (0 of which
binary) and 0 continuous</font>
<br><font size=2 face="sans-serif">218 integer have nonzero objective,
0 have zero objective, 8 different nonzero (taking abs)</font>
<br><font size=2 face="sans-serif">48 variables have objective of 1</font>
<br><font size=2 face="sans-serif">1 variables have objective of 4</font>
<br><font size=2 face="sans-serif">28 variables have objective of 16.29</font>
<br><font size=2 face="sans-serif">28 variables have objective of 31.58</font>
<br><font size=2 face="sans-serif">8 variables have objective of 233.333</font>
<br><font size=2 face="sans-serif">35 variables have objective of 1235.43</font>
<br><font size=2 face="sans-serif">35 variables have objective of 1430.12</font>
<br><font size=2 face="sans-serif">35 variables have objective of 2441.3</font>
<br><font size=2 face="sans-serif">Replacing model - 7 new variables</font>
<br><font size=2 face="sans-serif">Cbc0012I Integer solution of 594089.87
found by DiveCoefficient after 0 iterations and 0 nodes (0.19 seconds)</font>
<br><font size=2 face="sans-serif">Cbc0038I Full problem 353 rows 225 columns,
reduced to 307 rows 135 columns - too large</font>
<br><font size=2 face="sans-serif">Cbc0031I 11 added rows had average density
of 185.27273</font>
<br><font size=2 face="sans-serif">Cbc0013I At root node, 11 cuts changed
objective from 497140.24 to 499066.93 in 100 passes</font>
<br><font size=2 face="sans-serif">Cbc0014I Cut generator 0 (Probing) -
0 row cuts average 0.0 elements, 4 column cuts (4 active) in 0.768
seconds - new frequency is 1</font>
<br><font size=2 face="sans-serif">Cbc0014I Cut generator 1 (Gomory) -
1621 row cuts average 213.4 elements, 0 column cuts (11 active) in
0.561 seconds - new frequency is 1</font>
<br><font size=2 face="sans-serif">Cbc0014I Cut generator 2 (Knapsack)
- 0 row cuts average 0.0 elements, 0 column cuts (0 active) in 0.045
seconds - new frequency is -100</font>
<br><font size=2 face="sans-serif">Cbc0014I Cut generator 3 (Clique) -
0 row cuts average 0.0 elements, 0 column cuts (0 active) in 0.001
seconds - new frequency is -100</font>
<br><font size=2 face="sans-serif">Cbc0014I Cut generator 4 (MixedIntegerRounding2)
- 0 row cuts average 0.0 elements, 0 column cuts (0 active) in 0.106
seconds - new frequency is -100</font>
<br><font size=2 face="sans-serif">Cbc0014I Cut generator 5 (FlowCover)
- 0 row cuts average 0.0 elements, 0 column cuts (0 active) in 0.235
seconds - new frequency is -100</font>
<br><font size=2 face="sans-serif">Cbc0014I Cut generator 6 (TwoMirCuts)
- 225 row cuts average 165.6 elements, 0 column cuts (0 active) in
0.143 seconds - new frequency is -100</font>
<br><font size=2 face="sans-serif">Segmentation fault (core dumped)</font>
<br><font size=2 face="sans-serif">[acw@ARVON coin-Cbc]$ </font>