X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FComparisons.hs;h=3bf4e246bcfba473634b255fb1befb8187a84b8f;hb=3f7331f579118687cd73b977ce6aa7d401f88a09;hp=6d8dc70d846e08159c9c4ae6ea49b11a530a25a2;hpb=8c8a0f9d8df50b2fe29562790360dd615cf3e56a;p=spline3.git

diff --git a/src/Comparisons.hs b/src/Comparisons.hs
index 6d8dc70..3bf4e24 100644
--- a/src/Comparisons.hs
+++ b/src/Comparisons.hs
@@ -1,5 +1,14 @@
 -- | Functions for comparing 'Double' values.
-module Comparisons
+module Comparisons (
+  (~=),
+  (~~=),
+  almost_equals,
+  kinda_equals,
+  nearly_equals,
+  nearly_ge,
+  non_very_positive_entries,
+  very_positive,
+  )
 where
 
 -- | epsilon is the value that will be used in all tests that require
@@ -8,6 +17,17 @@ where
 epsilon :: Double
 epsilon = 0.0001
 
+-- | A tiny margin of error.
+theta :: Double
+theta = 0.0000000000001
+
+-- | x almost equals y if x is within 'theta' of y.
+nearly_equals :: Double -> Double -> Bool
+nearly_equals x y = (abs (x - y)) < theta
+
+-- | Nearly greater-than or equal-to.
+nearly_ge :: Double -> Double -> Bool
+x `nearly_ge` y = (x > y) || (x `nearly_equals` y)
 
 -- | x almost equals y if x is within 'epsilon' of y.
 almost_equals :: Double -> Double -> Bool