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我认为这可以归结为愚蠢的类型错误,但我无法弄清楚。我有以下代码:为什么我在这种情况下使用Data.Array.Repa.Algorithms.Matrix.mmultP得到类型错误?
{-# LANGUAGE TypeOperators #-}
import qualified Data.Array.Repa as R
import System.Random
import Data.Random.Normal
import Data.List
import Data.Function
import qualified Data.Array.Repa.Algorithms.Matrix as M
weights:: (Int,Int)->(Double,Double) -> R.Array R.U (R.Z R.:. Int R.:. Int) Double
weights (nodes,features) range = R.fromListUnboxed (R.Z R.:. nodes R.:. features) values
where
values = take (nodes * features) $ randomRs range gen
gen = mkStdGen 1
powerIteration :: R.Array R.U (R.Z R.:. Int R.:. Int) Double -> R.Array R.U (R.Z R.:. Int R.:. Int) Double
powerIteration m = M.mmultP m rb
where
rb = weights (rows,1) (0,1)
(R.Z R.:. _ R.:. rows) = R.extent m
main = do
let matrix = weights (10,3) (0,1)
print $ powerIteration matrix
这将创建一个二维阵列10行和3列,我想利用的(使用M.mmultP)的点积与一维阵列的惹巴表示的随机数(在0,1之间),列长度等于2D数组的行数。我在ghci中得到了类似的工作,但是这可能会产生这个错误;
Couldn't match type ‘R.Array R.U R.DIM2 Double’ with ‘Double’
Expected type: R.Array R.U ((R.Z R.:. Int) R.:. Int) Double
Actual type: R.Array
R.U ((R.Z R.:. Int) R.:. Int) (R.Array R.U R.DIM2 Double)
In the expression: M.mmultP m rb
In an equation for ‘powerIteration’:
powerIteration m
= M.mmultP m rb
where
rb = weights (rows, 1) (0, 1)
(R.Z R.:. _ R.:. rows) = R.extent m
这是一个类型错误,但我似乎无法弄清楚。有人可以帮我吗?
'mmultP'不* *并行工作,所以它在IO单子运行。或者将其更改为'mmultS' - 执行相同的操作,但是按顺序执行,或者将'powerIteration'的类型更改为'R.Array ... - > IO(R.Array ...)' – user2407038
哇,我没有注意并行和顺序之间的不同功能签名。如果你把它写成答案,我会接受它作为答案。 – stian