Excel Solver Problem not an optimal solution

[MarkZuckerberg]

I am using solver GRG nonlinear, to solve this problem.. i have 7 sets of 8 items selected out of 15 total. The solver choosing the changing cells the solver
will try to insert integer values into the cells, and th goal is to have as many combinations that are less similar to each other, by using a countif function to count
which of the 7 sets have values in common with all the others. However the solver gives me a solution that is a higher total than my own manual solution,
any ideas how to get it to solve it the right way?

 

[shg]

If I understand your question ...

There are =combin(15,8) = 6435 ways to choose 8 items from 15.

There are =combin(6435, 7) ~ 9E22 to select 7 of those combinations.

If Solver could evaluate a million arrangements a second, it would take a billion years to evaluate them all.

Solver is great at solving smooth problems, but this isn't one, and it's probably the wrong tool. I think (again, if I understand your question) you need a different approach.

 

[MarkZuckerberg]

Hey found a solution, i had to take away the unique requirement in solver since this conflicts with the bounds, then i added some countifs to get unique items in sets and this worked with evolutionary solver just fine.

 

[shg]

Good job.