Merge branch 'InitFromHDF5' of github.com:EXP-code/EXP into InitFromHDF5

Author: Martin D. Weinberg

src/Component.H

@@ -216,9 +216,10 @@ struct loadb_datum
 
   <li> The datatype for the <code>m</code>, <code>x</code>,
   <code>y</code>, <code>z</code>, <code>u</code>, <code>v</code>,
-  <code>w</code> and <code>aux_float_*</code> datasets maybe float or
-  double (i.e. float32 or float64) but they all must are assumed to
-  have the same datatype as <code>m</code>.
+  <code>w</code> and <code>aux_float_*</code> datasets may be float or
+  double (i.e. float32 or float64).  Each dataset's precision is
+  detected independently, so datasets may have mixed precision within
+  the same file.
 
   </ol>
 */

src/Component.cc

@@ -1699,16 +1699,21 @@ void Component::read_bodies_and_distribute_hdf5(void)
     // Offset into the next node's data in the HDF5 datasets
     offset += nbodies_table[0];
 
-    unsigned icount, ibufcount;
     for (int n=1; n<numprocs; n++) {
 
+      // Some ranks may legitimately receive 0 particles (e.g., more ranks than particles).
+      // In that case, ship an empty batch and skip all dataset reads.
+      if (nbodies_table[n] == 0) {
+        pf->ShipParticles(n, 0, 0);
+        continue;
+      }
+
       // Read core PSP fields
       if (has_index) {
         index = particles_group.getDataSet("index")
           .select({offset}, {nbodies_table[n]}).read<std::vector<unsigned long>>();
       }
       m = read_dataset("m", offset, nbodies_table[n]);
-
       x = read_dataset("x", offset, nbodies_table[n]);
       y = read_dataset("y", offset, nbodies_table[n]);
       z = read_dataset("z", offset, nbodies_table[n]);

utils/PhaseSpace/hdf5bods.cc

@@ -116,9 +116,11 @@ createFilterProps(const std::vector<hsize_t>& chunk_dims,
   HighFive::DataSetCreateProps props;
   props.add(HighFive::Chunking(chunk_dims));
 
+  // For most compressors, applying shuffle improves compression for floating-point data.
+  // (Blosc can do its own shuffling internally; shuffle-only/checksum-only are handled below.)
   if (filter_id != 3 && filter_id != 4 && filter_id != 32001) {
+    props.add(HighFive::Shuffle());
   }
-  
   hid_t plist_id = props.getId();
   std::vector<unsigned int> cd_values;