Fix a bug in the relative error.

diff --git a/src/FEM/R1.hs b/src/FEM/R1.hs
index 28317a6faecabaf0a079215a192f961a7d5e5be3..9ce8387e8f5ec980fc252a17bf5698f0510073cf 100644 (file)
--- a/src/FEM/R1.hs
+++ b/src/FEM/R1.hs
@@ -615,8 +615,7 @@ relative_error_pointwise :: forall m n l a.
                          -> a -- ^ The point @x@ at which to compute the error.
                          -> a
 relative_error_pointwise pde params u x =
-  cent * ( u_exact - u_fem ) / u_exact
+  cent * ( abs $ (u x) - u_fem ) / ( abs $ u x )
   where
-    u_exact = abs $ u x
     u_fem = evaluate' (solution pde params) x
     cent = fromInteger 100