Merge branch 'dev' into update_perftest

1 files changed, 41 insertions, 0 deletions

diff --git a/Source/Utils/WarpXUtil.cpp b/Source/Utils/WarpXUtil.cpp
index 4a884330a..a5ea6d75a 100644
--- a/Source/Utils/WarpXUtil.cpp
+++ b/Source/Utils/WarpXUtil.cpp
@@ -3,6 +3,7 @@
 #include <WarpXUtil.H>
 #include <WarpXConst.H>
 #include <AMReX_ParmParse.H>
+#include <WarpX.H>
 
 using namespace amrex;
 
@@ -95,3 +96,43 @@ void ConvertLabParamsToBoost()
       pp_wpx.addarr("fine_tag_hi", fine_tag_hi);
     }
 }
+
+/* \brief Function that sets the value of MultiFab MF to zero for z between 
+ * zmin and zmax.
+ */
+void NullifyMF(amrex::MultiFab& mf, int lev, amrex::Real zmin, amrex::Real zmax){
+    BL_PROFILE("WarpX::NullifyMF()");
+#ifdef _OPENMP
+#pragma omp parallel if (Gpu::notInLaunchRegion())
+#endif
+    for(amrex::MFIter mfi(mf, amrex::TilingIfNotGPU()); mfi.isValid(); ++mfi){
+        const amrex::Box& bx = mfi.tilebox();
+        // Get box lower and upper physical z bound, and dz
+        const amrex::Real zmin_box = WarpX::LowerCorner(bx, lev)[2];
+        const amrex::Real zmax_box = WarpX::UpperCorner(bx, lev)[2];
+        amrex::Real dz  = WarpX::CellSize(lev)[2];
+        // Get box lower index in the z direction
+#if (AMREX_SPACEDIM==3)
+        const int lo_ind = bx.loVect()[2];
+#else
+        const int lo_ind = bx.loVect()[1];
+#endif
+        // Check if box intersect with [zmin, zmax]
+        if ( (zmax>zmin_box && zmin<=zmax_box) ){
+            Array4<Real> arr = mf[mfi].array();
+            // Set field to 0 between zmin and zmax
+            ParallelFor(bx,
+                [=] AMREX_GPU_DEVICE(int i, int j, int k) noexcept{
+#if (AMREX_SPACEDIM==3)
+                    const Real z_gridpoint = zmin_box+(k-lo_ind)*dz;
+#else
+                    const Real z_gridpoint = zmin_box+(j-lo_ind)*dz;
+#endif 
+                    if ( (z_gridpoint >= zmin) && (z_gridpoint < zmax) ) {
+                        arr(i,j,k) = 0.;
+                    };
+                }
+            );
+        }
+    }
+}