Hi guys, been trying to figure out for a while now how I can solve this problem. I've implemented my own type of array, it's called NdArray. The way it works is as follow: It has a buffer (an array of something), a shape (list of dimensions), strides (list of steps) and an offset. Imagine we have a NdArray with a buffer of 9 numbers [1, 2, 3, 4, 5, 6, 7, 8, 9], shape [3, 3] (square matrix) and this leads to a list of strides [3, 1]. This last one means, there is a jump of 3 numbers for each of the first dimension. Better visualised:
buffer => [1, 2, 3, 4, 5, 6, 7, 8, 9] view of this buffer with shape [3, 3] => [ 1, 2, 3 , 4, 5, 6 , 7, 8, 9 ] Now, imagine I change the strides to be [2, 2], that means, I'm jumping one per dimension (in this square matrix I'm jumping one column and one row). The result is: [ 1, 3 , 7, 9 ] I'm jumping one number in the last dimension, and an entire row in the first dimension. Shape is now [2, 2]. So I have all this implemented already here https://github.com/jscriptcoder/elm-ndarray. This is port of ndarray by Mikola Lysenko, https://github.com/scijs/ndarray. But I got stuck how to walk this array. I'm trying to implement map, filter and fold (foldl), and to do so I must be able to walk this array, which is not that trivial (or at least not for me). I have implemented a function "index" which takes a location in the form of list of Int and calculates the index based on shape, strides and offset. So I'm trying to find a way to implement this functionality: For example, for a [3, 3] shape then nextLocation [0, 0] => Just [0, 1] nextLocation [0, 1] => Just [0, 2] nextLocation [0, 2] => Just [1, 0] nextLocation [1, 0] => Just [1, 1] nextLocation [1, 1] => Just [1, 2] ... nextLocation [2, 2] => Nothing By far not an expert in functional programming, maybe someone can help me to figur this one out? Thanks a lot. Fran -- 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.
