howellg@idec.UUCP (Gareth Howell) (08/05/85)
Hi, I'm looking for any packages that run under UNIX (any variety) that implement linear programming algorithms that could be used for network planning etc. Any pointers would be gratefully received. Thanks in advance gareth. -- Gareth Howell <howellg@idec.UUCP> <UK>ukc!stc!idec!howellg STC IDEC LIMITED Stevenage Herts England +44 (0)438 738294
rimey@ucbvax.ARPA (Ken Rimey) (08/12/85)
>I'm looking for any packages that run under UNIX (any variety) that >implement linear programming algorithms that could be used for network >planning etc. > Gareth Howell <howellg@idec.UUCP> > <UK>ukc!stc!idec!howellg You can use the IMSL programs zx0lp, zx3lp, and zx4lp. However, these programs have been known to give absurd results on occcasion. When run on single precision on a Vax-750 zx3lp and zx4lp gave nonsense results with as few as 4 variables. Since zx3lp is just a front-door program for zx0lp, one assumes that zx0lp fails as well. Surprisingly, the double precision versions of these routines work just fine in most cases. Only on large problems (e.g. 72 variables, 25 equality constraints) do they occasionally fail. Even in those cases the failure is only in one out of 50 cases, and carries a distinct signature. When the objective function and the dual objective function differ, the routine has bombed. In short, the double precision routines are usable in most cases, but you should watch out for mistakes. There is a Nag routine (E04mbf?) that does linear programming. It is available on Mark 11 Nag but not on earlier version. I don't know how well it works. Lorenzo Sadun sadun@ucbbach.BERKELEY.EDU "Stupidity Knows No Bounds", and "Dirac Delta Del Dot Duck"