1 files changed, 62 insertions, 0 deletions
diff --git a/src/id_noise.c b/src/id_noise.c
new file mode 100644
index 0000000..e94ec2b
--- /dev/null
+++ b/src/id_noise.c
@@ -0,0 +1,62 @@
+/*
+  IDRandom
+
+  Denis Pollney <pollney@aei.mpg.de>
+  14 February 2002
+
+  Put random data into the evolution variables for robust stability
+  testing a-la-winicour.
+
+  $Header$
+*/
+
+#include <stdlib.h>
+
+#include "noise.h"
+
+#include "cctk_Arguments.h"
+#include "cctk_Parameters.h"
+
+void
+add_noise_to_group (int idx, const char* optstring, void* cctkGH)
+{
+  int i, j, k, ijk;
+  CCTK_REAL* data;
+  CCTK_REAL amplitude;
+  CCTK_REAL offset;
+  cGH* GH = cctkGH;
+  int type;
+
+  data = (CCTK_REAL*) CCTK_VarDataPtrI(GH, 0, idx);
+
+  amplitude = *((CCTK_REAL*) CCTK_ParameterGet("amplitude", "Noise", &type))
+    / RAND_MAX;
+  offset = 0.5 * amplitude;
+
+  for (k=1; k< GH->cctk_lsh[2]-1; ++k)
+    {
+      for (j=1; j< GH->cctk_lsh[1]-1; ++j)
+	{
+	  for (i=1; i< GH->cctk_lsh[0]-1; ++i)
+	    {
+	      ijk = CCTK_GFINDEX3D(GH, i, j, k);
+
+	      data[ijk] += RAND_VAL;
+      	    }
+	}
+    }
+}
+
+
+void
+id_noise(CCTK_ARGUMENTS)
+{
+  DECLARE_CCTK_ARGUMENTS
+  DECLARE_CCTK_PARAMETERS
+
+  if (CCTK_TraverseString(noisy_id_vars, add_noise_to_group, cctkGH,
+			  CCTK_GROUP_OR_VAR) < 0)
+    {
+      CCTK_WARN (1, "Failed to parse 'IDRandom::noisy_id_vars' parameter");
+    }
+}