Use unboxed array for the main matrix

Question

Use unboxed array for the main matrix

huffyhenry opened this issue 6 years ago · 5 comments

Answer 1 · 2018-12-01T19:30:13.000Z

See https://stackoverflow.com/questions/32123475/profiling-builds-with-stack for instructions how to profile with stack and https://making.pusher.com/memory-profiling-in-haskell/ for an example.

Answer 2 · 2018-12-09T13:09:34.000Z

Asked a question on SO https://stackoverflow.com/questions/53692617/memory-usage-of-a-recursive-array-in-haskell

Answer 3 · 2018-12-17T09:23:04.000Z

Relevant: https://stackoverflow.com/questions/38206377/possible-to-do-recursive-definitions-with-unboxed-vectors/38207838

Answer 4 · 2018-12-22T19:46:57.000Z

The cause of the high memory footprint is "boxing": as I understand it, Haskell keeps the full computation of the array entries instead of the final value. Use unboxed arrays instead. Things to keep in mind:

Only simple types can be held in unboxed arrays, how do we keep an Entry? Do we need two arrays here?
We need to define the entries in the correct order - not hard, since N-W arrays can be filled row by row.

Answer 5 · 2018-12-24T23:11:41.000Z

Example use of the key STUArray type: https://stackoverflow.com/questions/8197032/starray-documentation-for-newbies-and-state-st-related-questions