Bug in Solver parameters?

  • Thread starter Thread starter Greg Soulsby
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Greg Soulsby

I have created a solver applicaton for selecting project
combinations. One of the variables is "run_flag", whether
the project is run or not. This is implemented with the
parameter run_flags = binary.

The solver is run within a macro loop, (using different
levels of maximum_budget).

When run the solutions include run_flags with fractions
between 0 and 1. But it is supposed to be either 0 or 1.

I have tried making the paramter run_flags = integer,
run_flags > -.5 and run flags < 1.5 but that makes it
worse - not only are the solution values for run_flags
real numbers not integers but negative numbers are
provided as solutions. Having our suppliers pay us for
running our projects wont wash with them - but 10/10 for
creativity excell.

Am I doing something wrong? Workarounds?

Thanks

Greg Soulsby
 
Solver, as other optimization software, uses real numbers for most of
its work and only when it reaches a valid solution does it ensure that
binary (or integer) constraints are satisfied (or almost satisfied). I
suspect that in the cases where the binary constraint is not satisfied,
Solver failed to find a solution in the first place.

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Tushar Mehta
www.tushar-mehta.com
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Yes, I now know your are right. It helps to set some of the parameters differently to the default, which asume things like small changes in input do not make a major change in the output, which is not true for our binary conditions.

I think the "bug" is that the thing reports back "all conditions met" even when our binary conditions are not met.

Know of any more software we could try?

Thanks

Greg
 
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