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It's unclear to me what this is doing exactly -- is it finding the best ever? If not, why would the best change every time you run this?

Also, does anyone have pointers to a hash function discovery mechanism that discovers a good hash function for integer values within a specific range (i.e I know that my integer values are between, say, 10,000 and 200,000, for example) and I want to hash them into some optimal number of hash buckets?

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It's randomly trying values to find the best of the ones it has tried that run. The values would change between runs because you can't feasibly exhaust the search space in a single run to find the absolute best (+the order you try is random).

If you're just looking for "good" the best approach is almost always to just use a normal hash function. If your numbers are extremely large and the range extremely small you can offset so the minimum becomes 0 again and use a smaller/faster hash. If you're more looking for "perfect choice of the exact range" I think the closest you'll get is something like this randomized approach but modify the tests to occur on your interval.

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