Added `none` as an option for fields_to_plot (#2419)

* Added `none` as an option for fields_to_plot

* Added CI test case

* Further updates, for picmi and CI tests

* Skip the call to amrex::WriteMultiLevelPlotfile when writing no fields

* Now clears m_varnames_fields

* Don't allocate m_mf_output if no varnames

* Updated WarpX-tests.ini

3 files changed, 19 insertions, 10 deletions

diff --git a/Source/Diagnostics/Diagnostics.cpp b/Source/Diagnostics/Diagnostics.cpp
index caf9aea13..3259994bd 100644
--- a/Source/Diagnostics/Diagnostics.cpp
+++ b/Source/Diagnostics/Diagnostics.cpp
@@ -169,6 +169,10 @@ Diagnostics::BaseReadParameters ()
         );
     }
 
+    if (WarpXUtilStr::is_in(m_varnames_fields, "none")){
+        m_varnames_fields.clear();
+    }
+
     m_varnames = m_varnames_fields;
     // Generate names of averaged particle fields and append to m_varnames
     for (int ivar=0; ivar<m_pfield_varnames.size(); ivar++) {
diff --git a/Source/Diagnostics/FlushFormats/FlushFormatPlotfile.cpp b/Source/Diagnostics/FlushFormats/FlushFormatPlotfile.cpp
index 4655128d5..513d97f3a 100644
--- a/Source/Diagnostics/FlushFormats/FlushFormatPlotfile.cpp
+++ b/Source/Diagnostics/FlushFormats/FlushFormatPlotfile.cpp
@@ -71,15 +71,17 @@ FlushFormatPlotfile::WriteToFile (
     VisMF::Header::Version current_version = VisMF::GetHeaderVersion();
     VisMF::SetHeaderVersion(amrex::VisMF::Header::Version_v1);
     if (plot_raw_fields) rfs.emplace_back("raw_fields");
-    amrex::WriteMultiLevelPlotfile(filename, nlev,
-                                   amrex::GetVecOfConstPtrs(mf),
-                                   varnames, geom,
-                                   static_cast<Real>(time), iteration, warpx.refRatio(),
-                                   "HyperCLaw-V1.1",
-                                   "Level_",
-                                   "Cell",
-                                   rfs
-                                   );
+    if (varnames.size() > 0) {
+        amrex::WriteMultiLevelPlotfile(filename, nlev,
+                                       amrex::GetVecOfConstPtrs(mf),
+                                       varnames, geom,
+                                       static_cast<Real>(time), iteration, warpx.refRatio(),
+                                       "HyperCLaw-V1.1",
+                                       "Level_",
+                                       "Cell",
+                                       rfs
+                                       );
+    }
 
     WriteAllRawFields(plot_raw_fields, nlev, filename, plot_raw_fields_guards);
 
diff --git a/Source/Diagnostics/FullDiagnostics.cpp b/Source/Diagnostics/FullDiagnostics.cpp
index cb51301ee..5fb9abbcb 100644
--- a/Source/Diagnostics/FullDiagnostics.cpp
+++ b/Source/Diagnostics/FullDiagnostics.cpp
@@ -541,7 +541,10 @@ FullDiagnostics::InitializeBufferData (int i_buffer, int lev ) {
     // Allocate output MultiFab for diagnostics. The data will be stored at cell-centers.
     int ngrow = (m_format == "sensei" || m_format == "ascent") ? 1 : 0;
     // The zero is hard-coded since the number of output buffers = 1 for FullDiagnostics
-    m_mf_output[i_buffer][lev] = amrex::MultiFab(ba, dmap, static_cast<int>(m_varnames.size()), ngrow);
+    int const ncomp = static_cast<int>(m_varnames.size());
+    if (ncomp > 0) {
+        m_mf_output[i_buffer][lev] = amrex::MultiFab(ba, dmap, ncomp, ngrow);
+    }
 
 
     if (lev == 0) {