Define: _OPENMP -> AMREX_USE_OMP (#1520)

* Define: _OPENMP -> AMREX_USE_OMP

Replace the define check of `_OPENMP` with the explicit
backend control of `AMREX_USE_OMP` for parallel constructs.

Doing so avoids that we accidentially turn on OpenMP, e.g. if a dependency
pulls it in for linear algebra, I/O, etc. This can led to confusion if the
user explicitly requested a serial build. Also, we might want to use OpenMP
functionality here and there for auxiliary functions w/o having to use the
AMReX OpenMP backend, i.e. because we compile for GPUs.

* Add missing amrex::Gpu::notInLaunchRegion

8 files changed, 12 insertions, 12 deletions

diff --git a/Source/FieldSolver/FiniteDifferenceSolver/ComputeDivE.cpp b/Source/FieldSolver/FiniteDifferenceSolver/ComputeDivE.cpp
index baadd0cfc..bcc7c4460 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/ComputeDivE.cpp
+++ b/Source/FieldSolver/FiniteDifferenceSolver/ComputeDivE.cpp
@@ -63,7 +63,7 @@ void FiniteDifferenceSolver::ComputeDivECartesian (
     amrex::MultiFab& divEfield ) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(divEfield, TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
@@ -109,7 +109,7 @@ void FiniteDifferenceSolver::ComputeDivECylindrical (
     amrex::MultiFab& divEfield ) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(divEfield, TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
diff --git a/Source/FieldSolver/FiniteDifferenceSolver/EvolveB.cpp b/Source/FieldSolver/FiniteDifferenceSolver/EvolveB.cpp
index 0ca576da2..338cc31f9 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/EvolveB.cpp
+++ b/Source/FieldSolver/FiniteDifferenceSolver/EvolveB.cpp
@@ -63,7 +63,7 @@ void FiniteDifferenceSolver::EvolveBCartesian (
     amrex::Real const dt ) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Bfield[0], TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
@@ -122,7 +122,7 @@ void FiniteDifferenceSolver::EvolveBCylindrical (
     amrex::Real const dt ) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Bfield[0], TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
diff --git a/Source/FieldSolver/FiniteDifferenceSolver/EvolveBPML.cpp b/Source/FieldSolver/FiniteDifferenceSolver/EvolveBPML.cpp
index 6fc157653..fbc62f661 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/EvolveBPML.cpp
+++ b/Source/FieldSolver/FiniteDifferenceSolver/EvolveBPML.cpp
@@ -64,7 +64,7 @@ void FiniteDifferenceSolver::EvolveBPMLCartesian (
     const bool dive_cleaning) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Bfield[0], TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
diff --git a/Source/FieldSolver/FiniteDifferenceSolver/EvolveE.cpp b/Source/FieldSolver/FiniteDifferenceSolver/EvolveE.cpp
index db1d1fe1b..3762d3f71 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/EvolveE.cpp
+++ b/Source/FieldSolver/FiniteDifferenceSolver/EvolveE.cpp
@@ -71,7 +71,7 @@ void FiniteDifferenceSolver::EvolveECartesian (
     Real constexpr c2 = PhysConst::c * PhysConst::c;
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Efield[0], TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
@@ -165,7 +165,7 @@ void FiniteDifferenceSolver::EvolveECylindrical (
     amrex::Real const dt ) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Efield[0], TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
diff --git a/Source/FieldSolver/FiniteDifferenceSolver/EvolveEPML.cpp b/Source/FieldSolver/FiniteDifferenceSolver/EvolveEPML.cpp
index d5ef1179b..f93f68414 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/EvolveEPML.cpp
+++ b/Source/FieldSolver/FiniteDifferenceSolver/EvolveEPML.cpp
@@ -76,7 +76,7 @@ void FiniteDifferenceSolver::EvolveEPMLCartesian (
     Real constexpr c2 = PhysConst::c * PhysConst::c;
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Efield[0], TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
diff --git a/Source/FieldSolver/FiniteDifferenceSolver/EvolveF.cpp b/Source/FieldSolver/FiniteDifferenceSolver/EvolveF.cpp
index fdbab39ea..445b62fb6 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/EvolveF.cpp
+++ b/Source/FieldSolver/FiniteDifferenceSolver/EvolveF.cpp
@@ -69,7 +69,7 @@ void FiniteDifferenceSolver::EvolveFCartesian (
     amrex::Real const dt ) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Ffield, TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
@@ -122,7 +122,7 @@ void FiniteDifferenceSolver::EvolveFCylindrical (
     amrex::Real const dt ) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Ffield, TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
diff --git a/Source/FieldSolver/FiniteDifferenceSolver/EvolveFPML.cpp b/Source/FieldSolver/FiniteDifferenceSolver/EvolveFPML.cpp
index cdcab750d..1a49316dd 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/EvolveFPML.cpp
+++ b/Source/FieldSolver/FiniteDifferenceSolver/EvolveFPML.cpp
@@ -62,7 +62,7 @@ void FiniteDifferenceSolver::EvolveFPMLCartesian (
     amrex::Real const dt ) {
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Ffield, TilingIfNotGPU()); mfi.isValid(); ++mfi ) {
diff --git a/Source/FieldSolver/FiniteDifferenceSolver/MacroscopicEvolveE.cpp b/Source/FieldSolver/FiniteDifferenceSolver/MacroscopicEvolveE.cpp
index 4a2d940aa..448c9b57d 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/MacroscopicEvolveE.cpp
+++ b/Source/FieldSolver/FiniteDifferenceSolver/MacroscopicEvolveE.cpp
@@ -94,7 +94,7 @@ void FiniteDifferenceSolver::MacroscopicEvolveECartesian (
 
 
     // Loop through the grids, and over the tiles within each grid
-#ifdef _OPENMP
+#ifdef AMREX_USE_OMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for ( MFIter mfi(*Efield[0], TilingIfNotGPU()); mfi.isValid(); ++mfi ) {