There is an alphabet of following 16 characters: acdegilmnoprstuw. Hash of 9-letter word created based on this alphabet is provided and so is the hashing function. Would You kindly find the original word for us ?
Originally posted at Fog Creek careers page.
Use make: make run. The only non standard thing in makefile is location of the MinGW - remove/change as fit. It is also recommended to use OpenCL.dll found in Your PATH, not one in lib.
We have 9 letters in word, each letter is one of 16 characters. This gives us 2^38 total permutations. Quite a lot. We are going to split the iterations between 3 groups:
- iterate over first 3 letters on cpu, invoking opencl kernel each time
- with each kernel invocation we are going to create 2^16 work items('threads' loosely speaking), which is equal to iterating over 4 letters
- each work item is going to do 2^8 iterations
| letter: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|---|
| on: | cpu | cpu | cpu | kernel id | kernel id | kernel id | kernel id | inside kernel |
inside kernel |
You can find old version of this project here. It contains both GPU & CPU implementation, but it is much, much slower.