Lots of changes

lib/Petzval/Calculations.hs

@@ -0,0 +1,21 @@
+module Petzval.Calculations where
+
+import Control.Arrow
+import Data.Foldable
+import Linear
+
+
+
+foldl1' fn (x:xs) = foldl' fn x xs
+
+bimap2 :: (a -> b -> c) -> (a' -> b' -> c') -> (a,a') -> (b,b') -> (c,c')
+bimap2 af bf (a,b) (a',b') = (af a a', bf b b')
+
+rmsSize' :: Floating a => V2 a -> [V2 a] -> a
+rmsSize' centroid = sqrt . uncurry (/) . foldl1' (bimap2 (+) (+))  . map (quadrance . (^-^ centroid) &&& (const 1))
+
+rmsSize :: Floating a => [V2 a] -> a
+rmsSize = centroid >>= rmsSize'
+
+centroid :: Fractional a => [V2 a] -> V2 a
+centroid = uncurry (^/) . foldl1' (bimap2 (^+^) (+)) . map (flip (,) 1)