X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FComparisons.hs;fp=src%2FComparisons.hs;h=6d8dc70d846e08159c9c4ae6ea49b11a530a25a2;hb=8c8a0f9d8df50b2fe29562790360dd615cf3e56a;hp=b5d76d5b11d6da85ca386021be918041d83abd53;hpb=374d036a09ca086d73dabd7196d888ff76b90610;p=spline3.git

diff --git a/src/Comparisons.hs b/src/Comparisons.hs
index b5d76d5..6d8dc70 100644
--- a/src/Comparisons.hs
+++ b/src/Comparisons.hs
@@ -18,6 +18,20 @@ infix 4 ~=
 (~=) = almost_equals
 
 
+-- | Like 'almost_equals', except much more tolerant. The difference
+--   between the two arguments must be less than one percent of the sum
+--   of their magnitudes.
+kinda_equals :: Double -> Double -> Bool
+kinda_equals x y =
+    (abs (x - y)) < threshold
+    where
+      threshold = ((abs x) + (abs y)) / 100.0
+
+infix 4 ~~=
+(~~=) :: Double -> Double -> Bool
+(~~=) = kinda_equals
+
+
 -- | x is very positive if it is 'epsilon' greater than zero.
 very_positive :: Double -> Bool
 very_positive x =  x - epsilon > 0