[Cbc] reading SOS item from CPLEX LP files

[John Forrest]

Kish,

This was more difficult to fix than I expected.  The coding for readLp 
uses fscanf("%s") which is totally dependent on space as a separator.

I think I have fixed in trunk (you can just copy over CoinLpIO.?pp to 
stable.  I have tried it on all the .lp files I have - which is not that 
many.  Some files had lines with more than 100K characters which caused 
some problems.

Please can people check I have not introduced any bugs.  Also if you 
want any other cosmetic changes - now is the time to ask for them.

John Forrest
On 16/02/18 11:51, Kish Shen wrote:
> Hi,
>
> I posted about this to coin-discuss mailing list yesterday, but it has 
> not appear there, and there seems to be no messages for the list since 
> Sept 2017, so I am posting this here as well, in case something is 
> wrong with the coin-discuss mailing list.
>
> I am getting errors from Cbc when reading an LP format file generated 
> by CPLEX 12:
>
> ### CoinLpIO::readLp(): bad SOS item S1
>
> I assume this is from reading the SOS items in the LP file like:
>
>  s999:  S1 ::  x1154 : 1  x5539 : 2
>
> Looking at CoinLpIO.cpp, the code expects no space between S1 and ::
>
>             if 
> (next>=buff&&(!strncmp(next,"S1::",4)||!strncmp(next,"S2::",4))) {
>               setType = next[1]-'0';
>               gotStart=true;
>             } else {
>               // error
>               goodLine=0;
>             }
>
> I edited the LP file and changed all the 'S1 ::' to 'S1::', and I then 
> got errors about x1154: repeatedly.
> So it looks like the error handling does not advance to the next line 
> after finding an error.
>
> I edited removed all the spaces before ':' for the SOS items, and the 
> file was then read without errors.
>
> Should ReadLp be changed to read the SOS items generated by CPLEX with 
> the extra spaces?
>
> I am running the latest stable branch of Cbc 2.9, downloaded via svn 
> co about 2 days ago.
>
> Thanks and cheers,
>
> Kish
>
>
>
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