On Monday, November 20, 2017 at 5:29:25 PM UTC, Francisco Ramos wrote: > > Ultimately, I'd like to rewrite NumElm using the elm-ndarray. Not sure how > I'm gonna do this without writing kernel code. Linear algebra operations > such as Inverse, Pseudo-inverse, Singular value decomposition, Eigenvalues > and eigenvectors, etc... I simply have no idea how I'm gonna implement > this. Need to have a look at solutions in Haskell for inspiration. >
I suspect you are up against a tough impedance mismatch between immutable arrays for functional languages, and fast flat arrays for pure number crunching. The tree structured arrays for functional languages are designed to allow a new version to be created from an existing array, without copying the entire array. Well, a balance between copying the least amount whilst keeping the tree fairly shallow for fast access. Arrays of floats for number crunching ideally just want to be stored flat in RAM, so you can point an optimized for-loop at them or your GPU. You could also look at Java nio.Buffer for some inspiration? These allow off-heap 'direct' buffers to be created, but have an interface on the Java language side to manipulate them. You can for example take a 'slice' of such a buffer, and it give you a so-called flyweight object as the result, that is, a start offset and length into the original buffer, but sharing the same data. 'slice' therefore is a very efficient operation. This scheme won't translate into immutable functional data structures without modification. For example, to modify such a buffer in an immutable way, would mean copying the entire thing. I just mention it as a possible source of inspiration to help you think about your design. Perhaps this is already what you have in mind for ndarray? A structure that is more efficient for your use case, but that is wrapped in an immutable functional API to make it play nicely with the host language. -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
