Hi Phil, On 22/01/11 14:07, gutti wrote:
Dear Haskellers,
I'm looking for Vector and especially Matric interpolation ala:
z = interp2 (xMatrix, yMatrix, zMatrix, x, y)
- x and y can be single values or also vectors or matrices - indeally with the options nearest, linear, quadratic, qubic..
Any hope that there is something similar especially using the HMatrix matrices (Matrix Double). - If I have to code it any suggestions ?
Cheers Phil
I'm not sure if this is what you mean, as I'm not familiar with matlab, so apologies if this is totally a waste of time.. But I had a simple cubic interpolation implemented already, it wasn't too hard to lift it into matrices (there are many elevation permutations, I imagine), I used (fromLists ...stuff... toLists), but maybe there's a better way: {-# LANGUAGE NoMonomorphismRestriction #-} module Interpolate where import Numeric.LinearAlgebra import Data.List (zipWith5) -- cubic interpolation cubic t a b c d = let a1 = 0.5 * (c - a) a2 = a - 2.5 * b + 2.0 * c - 0.5 * d a3 = 0.5 * (d - a) + 1.5 * (b - c) in ((a3 * t + a2) * t + a1) * t + b -- boring manual lifting liftMatrix5 f a b c d e = let la = toLists a lb = toLists b lc = toLists c ld = toLists d le = toLists e in fromLists (zipWith5 (zipWith5 f) la lb lc ld le) -- test mt = (3><3) [0, 0.1 ..] ma = (3><3) [0, 1 ..] mb = (3><3) [0, 2 ..] mc = (3><3) [0, 3 ..] md = (3><3) [0, 4 ..] test = liftMatrix5 cubic mt ma mb mc md {- test output (3><3) [ 0.0, 2.1, 4.4 , 6.9, 9.6, 12.5 , 15.600000000000001, 18.9, 22.4 ] -} -- http://claudiusmaximus.goto10.org