Re: [Help-glpk] timing

[glpk xypron]

Hello Serveh,

extra.time is determined by coding that is not part of the glpk
package but of octave.

You can find the relevant code in
octave-3.2.4.tar\octave-3.2.4\src\DLD-FUNCTIONS\__glpk__.cc

double *time;
clock_t t_start = clock();
*time = (clock () - t_start) / CLOCKS_PER_SEC;
extra.assign ("time", octave_value (time));

Clocks_per_sec is only a multiplier not the resolution of the
clock() function.

ISO 9899 says:
The clock function returns the implementation’s best approximation
to the processor time used by the program since the beginning of
an implementation-defined era related only to the program invocation.

So clocks_per_sec may be 1000 but clock() may be incremented
once a second only. This is operating system dependent.

Try your code on a problem that needs several seconds
to solve.

If you still get extra.time = 0, please, post you problem to
the octave list.

Best regards

Xypron


-------- Original-Nachricht --------
> hi ,
> one more question, what is the precision for extra.time in  [xmin, fmin, 
> status, extra] = glpk (c, a, b, lb, ub, ctype, vartype, s, param)
> because for every instance of  my MIP problem, I just get zero for time 
> in a case I get the feasible solution.
> bests,
> Serveh

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