[Haskell-beginners] numerical integration over lists

Thomas Engel thomas.engel1 at gmx.net
Sun Feb 5 09:19:02 CET 2012


I have two list (one with x values, the other with y values)
What I want to do is a numercial integration according the following formula:

Result x2 = Result x1 + ((y(x1) + y(x2))/2) * (x2 -x1)

and put the result in another list.

below my first try:

integriereListe [][]  = [0.0]
integriereListe (x:xs) (y:ys)   = ((y - y2) /2) * (x2 -x)
                                  x2 = head xs
                                  y2 = head ys    

but I got the failure

 Couldn't match type `[t0]' with `[[t0]]'
    In the pattern: y : ys
    In an equation for `integriereListe':
        integriereListe (x : xs) (y : ys)
          = ((y - y2) / 2) * (x2 - x)
              x2 = head xs
              y2 = head ys

another problem is how get the result  x1 (see above)

any hints are welcome.


More information about the Beginners mailing list