repa Questions
1
Solved
I am confused about why the REPA function computeP packs its result in a monad. It has the following type signature.
computeP :: (Load r1 sh e, Target r2 e, Source r2 e, Monad m) =>
Array r1 s...
2
In my recent work with Gibbs sampling, I've been making great use of the RVar which, in my view, provides a near ideal interface to random number generation. Sadly, I've been unable to make use of ...
Unbridle asked 27/6, 2012 at 16:27
1
Solved
I am trying this REPA library, and i want to process an image in both ways, parallel and sequentially.
I can read the image (with other library, DevIL) and process it with computeP (parallel). Her...
3
Solved
Imagine I want to map a function over an array, but the function has a type not just of
a -> b
but
a -> Int -> b
i.e. the function also takes an index. How do I do that?
2
In GNU Octave this code -
[e, ix] = min(X);
will return minimum element and it's location. How do you this in repa for arbitrary binary function?
This is what I came up with:
min x = z $ foldl...
1
I do not understand why this program using repa:
import Data.Array.Repa
import Data.Array.Repa.Algorithms.Matrix
import Data.Functor.Identity
go = runIdentity $ do
let mat = fromListUnboxed (ix2...
Subtile asked 13/6, 2016 at 5:40
0
I have coded two implementations of an algorithm to calculate all the eigenvalues and eigenvectors of a symmetric matrix. One implementation uses the REPA library
https://github.com/felipeZ/Haske...
1
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Background
I am using repa more as a "management" tool. I pass around reactive-bananas AddHandlers in an Array: Array D DIM2 (AddHandler Bool).
Currently I am using this kludge:
mapMArray :: (Mo...
0
In Repa, I would like to apply a certain d-dimensional linear transform in parallel across the innermost dimension of my array, i.e., on all "column" vectors.
In general, such a transformation can...
Millisent asked 11/6, 2014 at 0:4
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Repa and Accelerate API Similarity
The Haskell repa library is for automatically parallel array computation on CPUs. The accelerate library is automatic data parallelism on GPUs. The APIs are quit...
Landri asked 21/4, 2014 at 17:13
2
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I'm exploring the Haskell repa library by trying out the multitude of programming examples. I'm aiming to implementation common image processing algorithms using repa.
Repa examples
There are som...
1
The Problem
I'm trying to understand how Repa works and I was plaing with a "blur" example code from Repa Examples package. The code uses stencil2 Quasi Quote:
[stencil2| 2 4 5 4 2
4 9 12 9 4
...
Koumis asked 3/11, 2013 at 2:47
1
I have written a simulation of the outer planets of the solar system using the Euler symplectic method and implemented this a) using repa and b) using yarr.
yarr seems to perform about x30 quicker...
1
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I recently read the paper on upcoming generalized stream fusion in vector and DPH libraries. It seems to be very interesting development. I am now starting to experiment with DPH (starting with GHC...
Busty asked 9/3, 2013 at 19:5
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Documentation says,
Sometimes you want to control exactly when in GHC's pipeline the INLINE pragma is switched on.
Why should I ever want this? (Except when I also use RULES pragma, in this c...
Flier asked 21/1, 2013 at 20:8
2
Solved
I'm writing a program that generates images, which I would like to bring into a Repa array. I'm currently using the type:
data Colour = Colour Double Double Double
to represent pixels, and I hav...
1
Solved
Two related questions.
Is there a reason why there is no mutable (ST monad) implementation of repa arrays? Equivalent to Data.Vector.Mutable but with a shape.
Related to this, how is one suppose...
1
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Suppose I want to price a call option using a finite difference method
and repa then the following does the job:
import Data.Array.Repa as Repa
r, sigma, k, t, xMax, deltaX, deltaT :: Double
m, n...
Sextain asked 29/12, 2012 at 13:31
1
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I want to achieve something similar to the bounded arrays in the standard array package but using repa arrays.
What is the nice and clean way to achieve this?
This is what I tried, but there must...
1
Solved
I'm loading an RGB image from disk with JuicyPixels-repa. Unfortunately the Array representation of the image is Array F DIM3 Word8 where the inner dimension is the RGB pixels. That's a bit incompa...
1
Solved
I have a piece of Haskell code that looks like this:
fst . f $ (Z :. i `div` 2)
Z and :. are taken from Repa library and are defined like this:
data Z = Z deriving (Show, Read, Eq, Ord)
infixl ...
2
Is it possible to compute an array which depends on the past value(s) (i.e., lesser indexes), in Repa? Initial part(s) of the array (e.g., a[0]) is given. (Note that I am using C-like notation to i...
2
Solved
To be more specific, I have the following innocuous-looking little Repa 3 program:
{-# LANGUAGE QuasiQuotes #-}
import Prelude hiding (map, zipWith)
import System.Environment (getArgs)
import Dat...
Pavla asked 25/5, 2012 at 0:34
2
Solved
I'm using GHC 7.4.1 to try to compile a program that uses Repa. But partway through compilation, I'm running out of memory. With ghc -v, I can see that it's getting stuck in the SpecConstr phase.
...
Rosinweed asked 13/4, 2012 at 18:2
2
Solved
There is a basic monad question in here, unrelated to Repa, plus several Repa-specific questions.
I am working on a library using Repa3. I am having trouble getting efficient parallel code. If I m...
Karenkarena asked 15/3, 2012 at 2:56
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