Hi Matthieu, Yes, I made that mistake. As you mentioned, the strides are [6, 2].
Thanks for the correction. Fran On Mon, Dec 4, 2017, 07:40 Matthieu Pizenberg <[email protected]> wrote: > Hi Francisco, > I think there is a confusion here. If you keep the same buffer, your > matrice [1 3; 7 9] will be represented by { strides = (6, 2), shape = (2,2) > } not strides = (2,2). Because 6 is the jump from one line to the other (1 > to 7). > Let me know if I'm mistaking or not clear. > > > On Friday, December 1, 2017 at 11:22:16 PM UTC+8, Francisco Ramos wrote: >> >> 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. > -- 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.
