To answer the question in your subject, yes! We have a complex type. Not only does that make the code simpler and more obvious and idiomatic, but it's also more efficient because for this use you'd really prefer a strict pair type for "Point", and complex is strict in it's components.
On Sun, 2008-07-06 at 21:02 -0400, Michael Feathers wrote: > Decided a while ago to write some code to calculate the Mandelbrot set > using the escape iterations algorithm. Discovered after mulling it > about that I could just built it as an infinite list of infinite lists > and then extract any rectangle of values that I wanted: > > type Point = (Double, Double) > sq :: Double -> Double > sq x = x ^ 2 > > translate :: Point -> Point -> Point > translate (r0, i0) (r1, i1) = > (r0 + r1, i0 + i1) > > mandel :: Point -> Point > mandel (r, i) = > (sq r + sq i, 2 * r * i) > > notEscaped :: Point -> Bool > notEscaped (r, i) = > (sq r + sq i) <= 4.0 > > trajectory :: (Point -> Point) -> [Point] > trajectory pointFunction = > takeWhile notEscaped $ iterate pointFunction seed > where seed = (0.0, 0.0) > > escapeIterations :: (Point -> Point) -> Int > escapeIterations = > length . tail . take 1024 . trajectory > > mandelbrot :: Double -> [[Int]] > mandelbrot incrementSize = > [[ escapeIterations $ translate (x, y) . mandel > | x <- increments] > | y <- increments] where > increments = [0.0, incrementSize .. ] > > window :: (Int, Int) -> (Int, Int) -> [[a]] -> [[a]] > window (x0, y0) (x1, y1) = range x0 x1 . map (range y0 y1) where > range m n = take (n - m) . drop m > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
