minor fixes

.gitignore

@@ -10,3 +10,4 @@ billiard_words
 *.pnm
 *.png
 *.hi
+gmon.out

billiard_words.hs

@@ -11,18 +11,13 @@ wordlist = nub $ sortBy (comparing sl) [((p `div` gcd p q, q `div` gcd p q), slo
 
 -- only allows slopes 0 <= p/q <= 1
 slopeWord :: Int -> Int -> String
-slopeWord p q =
-    concat $ map word $ zipWith step list (tail list)
+slopeWord p q = concat $ map word $ zipWith step list (tail list)
     where
       p_ = p `div` gcd p q
       q_ = q `div` gcd p q
-      xmax = if (p_ - q_) `mod` 3 == 0 then q_ else 3*q_
-      list = [(x,y) | x <- ([0..xmax] :: [Int]), let y = floor (fromIntegral x*fromIntegral p/fromIntegral q)]
-
-      step :: (Int,Int) -> (Int,Int) -> (Int,Int)
-      step (x1,y1) (x2,y2) = ((x1-y1) `mod` 3, y2 - y1)
-
-      word :: (Int,Int) -> String
+      xmax = if (p_-q_) `mod` 3 == 0 then q_ else 3*q_ :: Int
+      list = [(x,(x*p) `div` q) | x <- [0..xmax]]
+      step (x1,y1) (x2,y2) = ((x1-y1) `mod` 3, y2-y1)
       word (0,0) = "bc"
       word (1,0) = "ab"
       word (2,0) = "ca"

max_slope_picture_billiards/generate.hs

@@ -9,6 +9,6 @@ col = map (\(r,g,b) -> (round $ r*255, round $ g*255, round $ b*255)) colors ::
 main = do
   foo <- readFile "max_slopes_billiard"
   let dat = map (read.(!!2).words) $ lines foo :: [Int]
-  writeFile "max_slope_billiards.pnm" $ header ++ unlines [printf "%d %d %d" r g b | p <- dat, let (r,g,b) = col !! (p `mod` 10)]
+  writeFile "max_slope_billiards.pnm" $ header ++ unlines [printf "%d %d %d" r g b | p <- dat, let (r,g,b) = col !! (p `mod` 14)]
       where
         header = "P3\n300\n123\n255\n"