TestRKAB: Changed random noise function to deterministic pseudo noise…

… based on the sign of the cossine function

TestRKAB/par/noise.par

@@ -6,14 +6,14 @@ ActiveThorns = "
 "
 
 ###### Settings ######
-$final_time = 1.0
-$out_every_time = 0.25
+$final_time = 100.0
+$out_every_time = 1.0
 
 $start = -1.0
 $end = 1.0
 
-$ncells = 160
-$cfl = 0.25
+$ncells = 128
+$cfl = 0.9
 ######################
 
 # We are using a 5 point centered stencil
@@ -27,8 +27,6 @@ $out_every_it = ceil($out_every_time / $dt)
 
 TestRKAB::compute_error = no
 TestRKAB::initial_condition = "noise"
-TestRKAB::noise_seed = 100.0
-TestRKAB::noise_boundary = 1.0e-7
 
 CarpetX::poison_undefined_values = no
 CarpetX::verbose = no

TestRKAB/param.ccl

@@ -36,12 +36,7 @@ CCTK_REAL gaussian_width "width of Gaussian"
   (0:* :: ""
 } 1.0
 
-CCTK_INT noise_seed "Seed of the RNG for noise initial data"
+CCTK_REAL noise_boundary "Noise will be generated in the [-noise_boundary, noise_boundary] range"
 {
   *:* :: ""
-} 100
-
-CCTK_REAL noise_boundary "Nois will be generated in the [-noise_boundary, noise_boundary] range"
-{
-  *:* :: ""
-} 1.0e-7
+} 1.0e-10

TestRKAB/src/initial.cxx

@@ -48,28 +48,38 @@ extern "C" void TestRKAB_Initial(CCTK_ARGUMENTS) {
         });
 
   } else if (CCTK_EQUALS(initial_condition, "noise")) {
-    // Make sure our RNG structures are initialized only once, regardless of the
-    // number of threads used.
-    static std::mt19937_64 noise_engine{noise_seed};
-    static std::uniform_real_distribution<CCTK_REAL> noise_distrib{
-        -noise_boundary, noise_boundary};
-
     grid.loop_int<0, 0, 0>(
         grid.nghostzones,
         [&] CCTK_HOST(const Loop::PointDesc &p) CCTK_ATTRIBUTE_ALWAYS_INLINE {
-#pragma omp critical
-          {
-            const auto value{noise_distrib(noise_engine)};
-            phi(p.I) = value;
-            Pi(p.I) = value;
-            Dx(p.I) = value;
-            Dy(p.I) = value;
-            Dz(p.I) = value;
-          }
+          using std::cos;
+
+          const auto noise_func{cos(10.0 * p.x / p.dx) *
+                                cos(10.0 * p.y / p.dy) *
+                                cos(10.0 * p.z / p.dz)};
+
+          const auto noise_value{noise_boundary *
+                                 (noise_func > 0 ? 1.0 : -1.0)};
+
+          phi(p.I) = noise_value;
+          Pi(p.I) = noise_value;
+          Dx(p.I) = noise_value;
+          Dy(p.I) = noise_value;
+          Dz(p.I) = noise_value;
         });
   } else {
     CCTK_VERROR("Unknown initial condition \"%s\"", initial_condition);
   }
+
+  // Regardless of ID choice, we initialize the previous RHS with zeros
+  grid.loop_int_device<0, 0, 0>(grid.nghostzones,
+                                [=] CCTK_DEVICE(const Loop::PointDesc &p)
+                                    CCTK_ATTRIBUTE_ALWAYS_INLINE {
+                                      phi_pre(p.I) = 0.0;
+                                      Pi_pre(p.I) = 0.0;
+                                      Dx_pre(p.I) = 0.0;
+                                      Dy_pre(p.I) = 0.0;
+                                      Dz_pre(p.I) = 0.0;
+                                    });
 }
 
 } // namespace TestRKAB