Option to have absorbing BC for particles, regardless of field BC (#1334)

* option to have absorbing BC for particles, regarless of field BC

* document input parameter particles.absorbing_bc

* minor, just add a small comment

* clarify doc and use better input parameter

* clarify documentation

1 files changed, 42 insertions, 0 deletions

diff --git a/Source/Particles/WarpXParticleContainer.cpp b/Source/Particles/WarpXParticleContainer.cpp
index 10ff7f19c..a50345f4b 100644
--- a/Source/Particles/WarpXParticleContainer.cpp
+++ b/Source/Particles/WarpXParticleContainer.cpp
@@ -889,3 +889,45 @@ WarpXParticleContainer::particlePostLocate(ParticleType& p,
         // to lower level.
     }
 }
+
+void
+WarpXParticleContainer::ApplyBoundaryConditions (ParticleBC boundary_conditions){
+    WARPX_PROFILE("WarpXParticleContainer::ApplyBoundaryConditions()");
+    for (int lev = 0; lev <= finestLevel(); ++lev)
+    {
+        for (WarpXParIter pti(*this, lev); pti.isValid(); ++pti)
+        {
+            auto GetPosition = GetParticlePosition(pti);
+            const Real xmin = Geom(lev).ProbLo(0);
+            const Real xmax = Geom(lev).ProbHi(0);
+#ifdef WARPX_DIM_3D
+            const Real ymin = Geom(lev).ProbLo(1);
+            const Real ymax = Geom(lev).ProbHi(1);
+#endif
+            const Real zmin = Geom(lev).ProbLo(AMREX_SPACEDIM-1);
+            const Real zmax = Geom(lev).ProbHi(AMREX_SPACEDIM-1);
+
+            ParticleTileType& ptile = ParticlesAt(lev, pti);
+            ParticleType * const pp = ptile.GetArrayOfStructs()().data();
+
+            // Loop over particles and apply BC to each particle
+            amrex::ParallelFor(
+                pti.numParticles(),
+                [=] AMREX_GPU_DEVICE (long i) {
+                    ParticleType& p = pp[i];
+                    ParticleReal x, y, z;
+                    GetPosition(i, x, y, z);
+#ifdef WARPX_DIM_3D
+                    if (x < xmin || x > xmax || y < ymin || y > ymax || z < zmin || z > zmax){
+                        if (boundary_conditions == ParticleBC::absorbing) p.id() = -1;
+                    }
+#else
+                    if (x < xmin || x > xmax || z < zmin || z > zmax){
+                        if (boundary_conditions == ParticleBC::absorbing) p.id() = -1;
+                    }
+#endif
+                }
+            );
+        }
+    }
+}