Hi Phil, On 22/01/11 23:13, gutti wrote:
- are t a b c d points or curve parameters ?
a b c d are points, t is the interpolation coefficient (between 0 and 1)
- how does lifting to matrix create a 1d spline to a 2d spline ? -- I don't see how it works
essentially, it creates a matrix of 1d splines, but now I see that this isn't what you wanted... for interpolated 2d matrix lookup, something like this, perhaps: -- using the cubic interpolator from earlier in the thread m @@>+ (x, y) = let (i, j) = (floor x, floor y) (s, t) = (x - fromIntegral i, y - fromIntegral j) cx j' = cubic s (m@@>(i-1,j')) (m@@>(i,j')) (m@@>(i+1,j')) (m@@>(i+2,j')) in cubic t (cx (j-1)) (cx j) (cx (j+1)) (cx (j+2)) test = let m = (16><16) [0 ..] n = 36 r = 5 (x0, y0) = (8, 8) in [ m @@>+ (x, y) | a <- [0 .. n - 1] , let a' = 2 * pi * fromIntegral a / fromIntegral n , let x = x0 + r * cos a' , let y = y0 + r * sin a' ] Claude -- http://claudiusmaximus.goto10.org