[Clp] Help - Input file .lp doesnot run

[Matthew Saltzman]

On Mon, 2012-07-16 at 16:40 -0400, Francois Margot wrote: 
> 
> On 07/16/2012 04:25 PM, Matthew Saltzman wrote:
> > On Mon, 2012-07-16 at 12:20 -0400, Francois Margot wrote:
> >> Hi Jack:
> >>
> >>   > I need some help. I´m testing a problem in Clp, I wrote it in .lp to
> >>   > input but the Clp doesn´t recognize the name of the constraints.
> >>   >
> >>   > I thought my .lp was wrong, but it works perfectly on GLPK, and it
> >>   > finds the optimal solution (obj 5169.13). I tried all the
> >>   > combinations I could imagine and all didn´t work. Clp tell the name
> >>   >contains illegal character ":", which the documentation tell, it works
> >>   > to identify the end of the name of each constraint.
> >>
> >>   > I have no idea how to solve this. The file is attached on email. The
> >>   > Clp version was 1.14.4.
> >>
> >>   > The most strange thing is I used GLPK to convert the .lp file to .mps
> >>   > and solved it on Clp. It works! So, I thought it could be some
> >>   > problem with the .lp files.
> >>
> >>   > All the constraints name are according to the function
> >>   > is_invalid_name( ). It must return 0 to all of them.
> >>
> >>   > It should be something stupid but I have no idea what it could be. I
> >>   > think that´s something wrong in the line 5.
> >>
> >>   > Does somebody know what how can I solve this problem?
> >>
> >> The problem is that there is a white space between '-' and '1250' in the
> >> rhs of constraint a2.
> >
> > Is that a bug or a feature?
> >
> 
> Neither. The code expects negative numbers to be written without white 
> space, as the code uses scanf() to get the rhs. No big deal to change 
> it, if necessary, but this case does not seem to rattle many users.

Where is this code?  If the input file really does work in GMPL and/or
AMPL and doesn't work for us, we should probably consider it a bug.

> 
> Francois

-- 
Matthew Saltzman
Clemson University Math Sciences
mjs AT clemson DOT edu