Print the dimension information to the HDF5 header group. Allows restart from a snapshot.

src/parallel_io.c

@@ -677,6 +677,8 @@ void write_output_parallel(struct engine* e, const char* baseName,
   writeAttribute(h_grp, "BoxSize", DOUBLE, e->s->dim, 3);
   double dblTime = e->time;
   writeAttribute(h_grp, "Time", DOUBLE, &dblTime, 1);
+  int dimension = (int)hydro_dimension;
+  writeAttribute(h_grp, "Dimension", INT, &dimension, 1);
 
   /* GADGET-2 legacy values */
   /* Number of particles of each type */

src/serial_io.c

@@ -739,6 +739,8 @@ void write_output_serial(struct engine* e, const char* baseName,
     writeAttribute(h_grp, "BoxSize", DOUBLE, e->s->dim, 3);
     double dblTime = e->time;
     writeAttribute(h_grp, "Time", DOUBLE, &dblTime, 1);
+    int dimension = (int)hydro_dimension;
+    writeAttribute(h_grp, "Dimension", INT, &dimension, 1);
 
     /* GADGET-2 legacy values */
     /* Number of particles of each type */

src/single_io.c

@@ -592,6 +592,8 @@ void write_output_single(struct engine* e, const char* baseName,
   writeAttribute(h_grp, "BoxSize", DOUBLE, e->s->dim, 3);
   double dblTime = e->time;
   writeAttribute(h_grp, "Time", DOUBLE, &dblTime, 1);
+  int dimension = (int)hydro_dimension;
+  writeAttribute(h_grp, "Dimension", INT, &dimension, 1);
 
   /* GADGET-2 legacy values */
   /* Number of particles of each type */