Fix compiler warnings and doctests.

[numerical-analysis.git] / src / Integration / Trapezoid.hs

diff --git a/src/Integration/Trapezoid.hs b/src/Integration/Trapezoid.hs
index c358feffec5d536f913d8e3a1c080391b17762d4..444d92d2eb9a0ed2e6911970f54cd88aafd71b3a 100644 (file)
--- a/src/Integration/Trapezoid.hs
+++ b/src/Integration/Trapezoid.hs
@@ -6,10 +6,8 @@ where
 import Misc (partition)
 
 import NumericPrelude hiding (abs)
-import Algebra.Absolute (abs)
 import qualified Algebra.Field as Field
 import qualified Algebra.RealField as RealField
-import qualified Algebra.RealRing as RealRing
 import qualified Algebra.ToInteger as ToInteger
 import qualified Algebra.ToRational as ToRational
 
@@ -48,11 +46,13 @@ trapezoid_1 f a b =
 --
 --   Examples:
 --
+--   >>> import Algebra.Absolute (abs)
 --   >>> let f x = x^2
 --   >>> let area = trapezoid 1000 f (-1) 1
 --   >>> abs (area - (2/3)) < 0.00001
 --   True
 --
+--   >>> import Algebra.Absolute (abs)
 --   >>> let area = trapezoid 1000 sin 0 pi
 --   >>> abs (area - 2) < 0.0001
 --   True