Custom Query (35 matches)

Grigory Sarnitskiy reports:

Hello! I'm using repa 2.1.1.5, so maybe this issue is gone already.

Nevertheless, repa's Show instance is a bit ambiguous, e.g. show of Maybe (Array DIM1 Int)

"Just Array (Z :. 1) [...]"

Wouldn't it be better to have

"Just (Array (Z :. 1) [...])"

just like elsewhere in Haskell? For example

show $ Just $ Just 5
"Just (Just 5)"

​http://stackoverflow.com/questions/8624760/repa-how-to-make-a-read-instance

Report from Chris Reade:

That is why I expected this code to work without the explicit seq , but these are needed to avoid the "Performing nested parallel computation sequentially" problem.

writeHeatMapBMP :: String 
                -> Array U DIM2 Double
                -> IO()
writeHeatMapBMP filename arr
  = do maxVal <- foldAllP max 0.0 arr
       minVal <- foldAllP min 0.0 arr
       arrImageOut <- minVal `seq` maxVal `seq`
                      computeP
                      $  R.map rgb8OfDouble
                      $  R.map (rampColorHotToCold minVal maxVal) arr
       writeImageToBMP filename arrImageOut

The implementation of foldAllP should ensure that the result is evaluated before it returns.