[Haskell-cafe] Matlab Style Logic Operations ala V1.*(V2>0) on Vectors and Matrices with HMatrix ??

[gutti]

Hi Henning, 

You definitly caught me on that little Germanism :-)

About Your comments - a lot to learn and take in, but it really helps. -
Thanks a lot.
I just manged to get the Matrix masking running code looks like (code A see
below). Two quick questions:

question 1.  u see the two commented lines I tried to get ur original line
running, but didn't know how to specify f

## Code ########

import Numeric.LinearAlgebra
import Graphics.Plot

matrix1 = fromLists [[0 .. 5],[30 .. 35],[50 .. 55]]
matrix2 = fromLists [[-1,2],[-3,4],[5,-6]]

-- matrix1 = buildMatrix 3 4 ( (r,c) -> fromIntegral r * fromIntegral c)
(3><4)
-- posPart v  =  mapVector (\a -> if a>=0 then a else 0) v 

-- function2map a1 a2 = (\a1 a2 -> if a1>=0 then a2/a1 else a1/a2)
matrixfunction x y = liftMatrix2 (zipVectorWith(\a1 a2 -> if a2>=0 then a1
else 0)) x y 

matrix3 = matrixfunction matrix1 matrix2

disp = putStr . disps 2
          
main = do 

  disp matrix1
  disp matrix2
--  disp matrix3
  mesh matrix1


#########


question 2: - the compiler comes up with some weired data type problem --
ghci has no problem this line :

matrixTest_Fail.hs:5:10:
    Ambiguous type variable `t' in the constraints:
      `Element t'
        arising from a use of `fromLists' at matrixTest_Fail.hs:5:10-38
      `Num t' arising from the literal `1' at matrixTest_Fail.hs:5:22
    Possible cause: the monomorphism restriction applied to the following:
      matrix2 :: Matrix t (bound at matrixTest_Fail.hs:5:0)
    Probable fix: give these definition(s) an explicit type signature
                  or use -XNoMonomorphismRestriction
 
## Code #####

import Numeric.LinearAlgebra
import Graphics.Plot

matrix1 = fromLists [[1,2],[3,4],[5,6]]
matrix2 = fromLists [[1,2],[3,4],[5,6]]

disp = putStr . disps 2

main = do 

  disp matrix1

#########
-- 
View this message in context: http://haskell.1045720.n5.nabble.com/Matlab-Style-Logic-Operations-ala-V1-V2-0-on-Vectors-and-Matrices-with-HMatrix-tp3312601p3315761.html
Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.