Henning Thielemann wrote:
On Wed, 13 Jun 2007, L.Guo wrote:
I already have one matrix of type [[a]] to store one image.
What I want to do is to devide the image into severial small blocks in same size.
To do that, I wrote this tool function.
chop :: Int -> [a] -> [[a]] chop _ [] = [] chop n ls = take n ls : chop n (drop n ls)
I assume that it is more efficient to use 'splitAt' instead of 'take' and 'drop'.
But I do not know how to use it to write the function.
chop blockHeight (map (chop blockWidth) image)
That would divide abcd efgh ijkl mnop into [ [ ab cd , ef gh ] , [ ij kl , mn op ] ] at block size 2. In any case, the original poster was not very clear about what they want... -- Dr. Janis Voigtlaender http://wwwtcs.inf.tu-dresden.de/~voigt/ mailto:voigt@tcs.inf.tu-dresden.de