Add support for groupID i/o in DM-only runs on single nodes.

src/single_io.c

@@ -53,6 +53,7 @@
 #include "stars_io.h"
 #include "tracers_io.h"
 #include "units.h"
+#include "velociraptor_io.h"
 #include "xmf.h"
 
 /**
@@ -646,6 +647,8 @@ void write_output_single(struct engine* e, const char* baseName,
   const struct spart* sparts = e->s->sparts;
   struct swift_params* params = e->parameter_file;
   const int with_cosmology = e->policy & engine_policy_cosmology;
+  const int with_stf = (e->policy & engine_policy_structure_finding) &&
+                       (e->s->gpart_group_data != NULL);
   const int with_cooling = e->policy & engine_policy_cooling;
   const int with_temperature = e->policy & engine_policy_temperature;
 
@@ -950,6 +953,11 @@ void write_output_single(struct engine* e, const char* baseName,
           /* This is a DM-only run without inhibited particles */
           N = Ntot;
           darkmatter_write_particles(gparts, list, &num_fields);
+          if (with_stf) {
+#ifdef HAVE_VELOCIRAPTOR
+            num_fields += velociraptor_write_gparts(gparts, list + num_fields);
+#endif
+          }
         } else {
 
           /* Ok, we need to fish out the particles we want */
@@ -965,6 +973,12 @@ void write_output_single(struct engine* e, const char* baseName,
 
           /* Write DM particles */
           darkmatter_write_particles(gparts_written, list, &num_fields);
+          if (with_stf) {
+#ifdef HAVE_VELOCIRAPTOR
+            num_fields +=
+                velociraptor_write_gparts(gparts_written, list + num_fields);
+#endif
+          }
         }
       } break;
 

src/swift_velociraptor_part.h

@@ -21,7 +21,13 @@
 
 #include "part_type.h"
 
-/* SWIFT/VELOCIraptor particle. */
+/**
+ * @brief SWIFT/VELOCIraptor particle.
+ *
+ * This should match the structure Swift::swift_vel_part
+ * defined in the file NBodylib/src/NBody/SwiftParticle.h
+ * of the VELOCIraptor code.
+ */
 struct swift_vel_part {
 
   /*! Particle ID. */

src/velociraptor_interface.c

@@ -532,7 +532,7 @@ void velociraptor_invoke(struct engine *e, const int linked_with_snap) {
 
     struct velociraptor_gpart_data *data = s->gpart_group_data;
 
-    /* Zero the array (#gpart not in groups have an ID of 0) */
+    /* Zero the array (gparts not in groups have an ID of 0) */
     bzero(data, nr_gparts * sizeof(struct velociraptor_gpart_data));
 
     /* Copy the data at the right place */

src/velociraptor_io.h

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (c) 2019 Matthieu Schaller (schaller@strw.leidenuniv.nl)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+#ifndef SWIFT_VELOCIRAPTOR_IO_H
+#define SWIFT_VELOCIRAPTOR_IO_H
+
+/* Config parameters. */
+#include "../config.h"
+
+INLINE static void velociraptor_convert_groupID(const struct engine* e,
+                                                const struct gpart* gp,
+                                                long long* ret) {
+
+  const ptrdiff_t offset = gp - e->s->gparts;
+  *ret = (e->s->gpart_group_data + offset)->groupID;
+}
+
+__attribute__((always_inline)) INLINE static int velociraptor_write_gparts(
+    const struct gpart* gparts, struct io_props* list) {
+
+  list[0] = io_make_output_field_convert_gpart("GroupID", LONGLONG, 1,
+                                               UNIT_CONV_NO_UNITS, gparts,
+                                               velociraptor_convert_groupID);
+
+  return 1;
+}
+
+#endif /* SWIFT_VELOCIRAPTOR_IO_H */