1 files changed, 86 insertions, 0 deletions
diff --git a/Source/Particles/ParticleCreation/DefaultInitialization.H b/Source/Particles/ParticleCreation/DefaultInitialization.H
new file mode 100644
index 000000000..f2f0dd3d8
--- /dev/null
+++ b/Source/Particles/ParticleCreation/DefaultInitialization.H
@@ -0,0 +1,86 @@
+#ifndef DEFAULTINITIALIZATION_H_
+#define DEFAULTINITIALIZATION_H_
+
+#include "AMReX_REAL.H"
+#include "AMReX_GpuContainers.H"
+
+#include <map>
+#include <string>
+
+/**
+ * \brief This set of initialization policies describes what happens
+ * when we need to create a new particle due to an elementary process.
+ * For example, when an ionization event creates an electron, these
+ * policies control the initial values of the electron's components.
+ * These can always be over-written later.
+ *
+ * The specific meanings are as follows:
+ *     Zero         - set the component to zero
+ *     One          - set the component to one
+ *     SignalingNan - set the component to a signalling nan. If you run
+ *                    with amrex.fpe_trap_invalid=1 AND built the code
+ *                    with gcc, this will throw an exception the first time
+ *                    it is used.
+ *     RandomTau    - a special flag for the "tau" component used by certain
+ *                    QED processes, which gets a random initial value.
+ *
+ */
+enum struct InitializationPolicy {Zero=0, One, SignalingNan, RandomTau};
+
+/**
+ * \brief This map sets the initialization policy for each particle component
+ * used in WarpX.
+ */
+static std::map<std::string, InitializationPolicy> initialization_policies = {
+    {"w",     InitializationPolicy::Zero },
+    {"ux",    InitializationPolicy::Zero },
+    {"uy",    InitializationPolicy::Zero },
+    {"uz",    InitializationPolicy::Zero },
+    {"Ex",    InitializationPolicy::Zero },
+    {"Ey",    InitializationPolicy::Zero },
+    {"Ez",    InitializationPolicy::Zero },
+    {"Bx",    InitializationPolicy::Zero },
+    {"By",    InitializationPolicy::Zero },
+    {"Bz",    InitializationPolicy::Zero },
+#ifdef WARPX_DIM_RZ
+    {"theta", InitializationPolicy::Zero},
+#endif
+    {"tau",   InitializationPolicy::RandomTau}
+};
+
+AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+amrex::ParticleReal initializeRealValue (const InitializationPolicy policy) noexcept
+{
+    switch (policy) {
+        case InitializationPolicy::Zero : return 0.0;
+        case InitializationPolicy::One  : return 1.0;
+        case InitializationPolicy::SignalingNan : {
+            return 1.0;
+        }
+        case InitializationPolicy::RandomTau : {
+            return 1.0;
+        }
+        default : {
+            amrex::Abort("Initialization Policy not recognized");
+            return 1.0;
+        }
+    }
+}
+
+AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+int initializeIntValue (const InitializationPolicy policy) noexcept
+{
+    switch (policy) {
+        case InitializationPolicy::Zero : return 0;
+        case InitializationPolicy::One  : return 1;
+        case InitializationPolicy::SignalingNan : {
+            return 1;
+        }
+        default : {
+            amrex::Abort("Initialization Policy not recognized");
+            return 1;
+        }
+    }
+}
+
+#endif