Implementation of sift algorithm

[wujilingfeng]

Recently, I implemented the sift algorithm (all its core algorithms have been implemented, just short of some basic assembly), and opened it up haskell-sift.

It still needs more professional optimization, because it is not as fast as opencv under the same CPU acceleration.
It would be better if awhile function could be optimized.

Due to the limited personal level, if anyone can provide professional guidance, this project will be beneficial to everyone.

[tmcdonell]

oh nice! I haven't looked in detail yet, but am curious to try it out.
What do you mean by optimising the awhile function?

[wujilingfeng]

I have updated the code, now it's very fast. The memory usage is still too high

[tomsmeding]

By the way， Why is permute defined like this (Exp a ->Exp a->Exp a)->Acc (Array sh' a)->(Exp sh->Exp (Maybe sh'))->Acc (Array sh a)->Acc (Array sh' a) rather than (Exp b ->Exp a->Exp a)->Acc (Array sh' a)->(Exp sh->Exp (Maybe sh'))->Acc (Array sh b)->Acc (Array sh' a)?

Because of the way permute is implemented. It shoots off an atomic update for every cell in the source array, and there are no guarantees whatsoever in which order those will be executed. That is also why the combination function must usually be commutative and associative for permute to give a well-defined, consistent answer. (If all updates are at distinct indices then these properties are not required, because then there is nothing to reorder.)

[wujilingfeng]

if permute is defined (Exp b ->Exp a->Exp a)->Acc (Array sh' a)->(Exp sh->Exp (Maybe sh'))->Acc (Array sh b)->Acc (Array sh' a), I can solve the memory problem.

[wujilingfeng]

If I want to implement histogram, what other good ways are there?

[wujilingfeng]

I've solved the memory problem and now it's very fast. Thank you for your guidance and suggestions. I will update the code later. I am also trying to install the accelerate library in Windows.
After that, I will also add visual programs, hoping that this project can bring benefits to everyone.
Thank you！