Add version of PC::Checkpoint that allows toggling off certain compon…

…ents. (#4264)

This is useful in the case that some components can be re-initialized
rather than read from the checkpoint file.

## Summary

## Additional background

## Checklist

The proposed changes:
- [ ] fix a bug or incorrect behavior in AMReX
- [ ] add new capabilities to AMReX
- [ ] changes answers in the test suite to more than roundoff level
- [ ] are likely to significantly affect the results of downstream AMReX
users
- [ ] include documentation in the code and/or rst files, if appropriate

Src/Particle/AMReX_ParticleContainer.H

@@ -768,6 +768,24 @@ public:
                      const Vector<std::string>& real_comp_names = Vector<std::string>(),
                      const Vector<std::string>& int_comp_names = Vector<std::string>()) const;
 
+    /**
+     * \brief Writes a particle checkpoint to file, suitable for restarting.
+     *        This version allows some components to be toggled off, if they
+     *        don't need to be stored in the chk file.
+     *
+     * \param dir The base directory into which to write (i.e. "plt00000")
+     * \param name The name of the sub-directory for this particle type (i.e. "Tracer")
+      * \param write_real_comp for each real component, whether or not we include that component in the file
+      * \param write_int_comp for each integer component, whether or not we include that component in the file
+     * \param real_comp_names vector of real component names
+     * \param int_comp_names vector of int component names
+     */
+    void Checkpoint (const std::string& dir, const std::string& name,
+                     const Vector<int>& write_real_comp,
+                     const Vector<int>& write_int_comp,
+                     const Vector<std::string>& real_comp_names,
+                     const Vector<std::string>& int_comp_names) const;
+
      /**
       * \brief Writes particle data to disk in the AMReX native format.
       *

Src/Particle/AMReX_ParticleIO.H

@@ -86,6 +86,21 @@ ParticleContainer_impl<ParticleType, NArrayReal, NArrayInt, Allocator, CellAssig
                             FilterPositiveID{}, true);
 }
 
+template <typename ParticleType, int NArrayReal, int NArrayInt,
+          template<class> class Allocator, class CellAssignor>
+void
+ParticleContainer_impl<ParticleType, NArrayReal, NArrayInt, Allocator, CellAssignor>
+::Checkpoint (const std::string& dir, const std::string& name,
+              const Vector<int>& write_real_comp,
+              const Vector<int>& write_int_comp,
+              const Vector<std::string>& real_comp_names,
+              const Vector<std::string>& int_comp_names) const
+{
+    WriteBinaryParticleData(dir, name, write_real_comp, write_int_comp,
+                            real_comp_names, int_comp_names,
+                            FilterPositiveID{}, true);
+}
+
 template <typename ParticleType, int NArrayReal, int NArrayInt,
           template<class> class Allocator, class CellAssignor>
 void