[Help-glpk] Re: GLPK on 64 bit Linux

[Andrew Makhorin]

> Yes you're right, a given input resource may be allocated
> differently and is the case. But one thing that should remain constant
> though is the totals, what I'm talking about is that the totals of the
> allocations at the end of a given input do not equal that input.

> By way of illustration, take the often quoted example where the
> farmer is allocating his land to grow wheat or barley subject to
> constraints. In the output results, even if there are multiple optima,
> all the land should be allocated to either wheat or barley, but I find
> cases where the total land in the output is less or greater than the
> amount coming in, and it's too great to be a rounding error.

It may happen that it is not profitable to allocate all the land
until you require all the land to be allocated by introducing an
appropriate equiality constraint.

> Now my resource allocation problem is clearly different than the
> simple example above, I have many different resources to be allocated
> subject to more constraints, but the problem I have is essentially the
> same as this analogy.

You can write the solution in a text file with glp_print_sol
and see if the optimality conditions are satisfied. If they are,
probably you missed some essential constraints. If not, please
write your instance in mps or better in glpk lp/mip format and post
it to me. Thanks.