Fixed error setting solution at special case of r=0

Closes Cactus/1085

Also made the gaussian in IDScalarWaveCXX consistent with gaussians in
the other ID thorns, hence new testsuite results.


git-svn-id: http://svn.cactuscode.org/arrangements/CactusWave/IDScalarWaveCXX/trunk@37 7ec00dc9-1e7a-42ad-bf73-a299ee168e72

1 files changed, 11 insertions, 2 deletions

diff --git a/src/InitialData.cc b/src/InitialData.cc
index 5e457d8..d5c6682 100644
--- a/src/InitialData.cc
+++ b/src/InitialData.cc
@@ -83,8 +83,17 @@ extern "C" void IDScalarWaveCXX_InitialData(CCTK_ARGUMENTS)
           CCTK_REAL R = sqrt(X*X + Y*Y + Z*Z);
 
           phi[index] = amplitude*exp( - sqr( (R - radius) / sigma ) );
-          phi_p[index] = amplitude*exp( - sqr( (R - radius - dt) / sigma ) );
-
+ 	  if (R == 0.0) 
+	  {
+	    phi_p[index] = amplitude*(1.0 - 2.0*dt*dt/sigma)*exp(-dt*dt/sigma);
+	  }
+	  else
+	  {
+	    phi_p[index] = amplitude/2.0*(R-dt)/R*
+	      exp( - sqr( (R - radius - dt)/ sigma ) )
+	      + amplitude/2.0*(R+dt)/R*
+	      exp( - sqr( (R - radius + dt)/ sigma ) );
+	  }
         } 
       }
     }