From: Wolfgang Bangerth <bangerth@math.tamu.edu>
Date: Mon, 29 Jun 2015 23:01:45 +0000 (-0500)
Subject: Avoid computing atan(y/x) where x=0.
X-Git-Tag: v8.3.0-rc1~75^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8fc44f99cc58f95d24f26ad1ec82c09547764e7a;p=dealii.git

Avoid computing atan(y/x) where x=0.

Rather, use atan2(y,x).
---

diff --git a/tests/codim_one/bem_integration.cc b/tests/codim_one/bem_integration.cc
index 063d2dd28b..9b03d82c94 100644
--- a/tests/codim_one/bem_integration.cc
+++ b/tests/codim_one/bem_integration.cc
@@ -165,7 +165,7 @@ LaplaceKernelIntegration<dim>::term_S (const Tensor<1,3> &r,
     *(
       - ra1*n/a1.norm() * asinh( r*a1/ra1.norm() )
       + ra2*n/a2.norm() * asinh( r*a2/ra2.norm() )
-      + rn_c * atan( ra1*ra2 / (r.norm()* (r*(a12))))
+      + rn_c * atan2( ra1*ra2, r.norm()* (r*a12) )
     );
 
   return integral;
@@ -185,7 +185,7 @@ LaplaceKernelIntegration<dim>::term_D (const Tensor<1,3> &r,
   cross_product(a12,a1,a2);
 
   double integral = 1./2./numbers::PI
-                    *atan( ra1*ra2 / (r.norm()* (r*(a12))));
+                    *atan2( ra1*ra2, (r.norm()* (r*a12)));
 
   return integral;