[Cbc] Segmentation fault 11 when providing initial solution in command line

[John Forrest]

Joel,

Unable to reproduce with latest stable.

I get

opening mipstart file ./Matching-pulp-simplify.sol.
MIPStart values read for 32 variables.
Continuous objective value is 745 - 0.00 seconds
Cgl0008I 15 inequality constraints converted to equality constraints
Cgl0004I processed model has 68 rows, 167 columns (162 integer (162 of 
which binary)) and 503 elements
Cutoff increment increased from 1e-05 to 0.9999
Cbc0045I MIPStart provided solution with cost 1195

or

opening mipstart file ./Matching-manual.sol.
MIPStart values read for 15 variables.
Continuous objective value is 745 - 0.00 seconds
Cgl0008I 15 inequality constraints converted to equality constraints
Cgl0004I processed model has 68 rows, 167 columns (162 integer (162 of 
which binary)) and 503 elements
Cutoff increment increased from 1e-05 to 0.9999
Cbc0045I Trying just fixing integer variables.
Cbc0045I Warning: mipstart values could not be used to build a solution.

So try latest version and see if that fixes.

John Forrest
Using On 27/12/15 19:54, Joel Cofield wrote:
> Hi All,
>
> I am trying to run cbc through the command line with an initial 
> solution but it does not work. My .lp and three tries at a .sol file 
> are attached.
>
> My first attempt uses a .sol file generated by an initial run of the 
> same MIP but does not provide all of the variables for some reason:
> cbc Matching-pulp.lp mips Matching-init-pulp.sol solve
> ...
> Cbc0045I MIPStart solution provided values for 1 of 162 integer 
> variables, 22 variables are still fractional.
>
> My second attempt was to simplify the solution file but I get a 
> segmentation fault:
> cbc Matching-pulp.lp mips Matching-init-pulp_simpler.sol solve
>
> So then I tried just making my own solution file and also received a 
> segmentation fault:
>
> cbc Matching-pulp.lp mips Matching-manual.sol solve
> Welcome to the CBC MILP Solver
> Version: 2.9.0
> Build Date: Feb 12 2015
>
> command line - 
> /Library/Python/2.7/site-packages/PuLP-1.5.6-py2.7.egg/pulp/solverdir/cbc/osx/64/cbc 
> Matching-pulp.lp mips Matching-manual.sol solve (default strategy 1)
>  CoinLpIO::readLp(): Maximization problem reformulated as minimization
> will open mipstart file ./Matching-manual.sol.
> mipstart values read for 15 variables.
> Continuous objective value is 745 - 0.00 seconds
> Cgl0008I 15 inequality constraints converted to equality constraints
> Cgl0004I processed model has 68 rows, 167 columns (162 integer (162 of 
> which binary)) and 503 elements
> Cutoff increment increased from 1e-05 to 0.9999
> Segmentation fault: 11
>
>
> If I just run cbc Matching-pulp.lp solve then cbc finds the optimal 
> solution.
>
> Why are these file causing memory issues? Are there mips file 
> standards I can follow or is this a bug?
>
> Thanks,
>
> Joel
>
>
>
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