Allow SWIFT snapshots to be reused as ICs explicitly

examples/parameter_example.yml

@@ -226,6 +226,7 @@ Statistics:
 InitialConditions:
   file_name:  SedovBlast/sedov.hdf5 # The file to read
   periodic:                    1    # Are we running with periodic ICs?
+  accept_snapshot:             0    # (Optional) Accept SWIFT snapshot field names when reading ICs.
   generate_gas_in_ics:         0    # (Optional) Generate gas particles from the DM-only ICs (e.g. from panphasia).
   cleanup_h_factors:           0    # (Optional) Clean up the h-factors used in the ICs (e.g. in Gadget files).
   cleanup_velocity_factors:    0    # (Optional) Clean up the scale-factors used in the definition of the velocity variable in the ICs (e.g. in Gadget files).

src/io_properties.h

@@ -209,6 +209,22 @@ INLINE static void safe_strcpy(char *restrict dst, const char *restrict src,
   dst[dst_len - 1] = '\0';
 }
 
+/**
+ * @brief Return a snapshot-output alias for legacy/singular IC field names.
+ *
+ * SWIFT follows GADGET-style singular names in ICs but writes plural field
+ * names in snapshots. Accepting these aliases lets a snapshot be reused as an
+ * IC without an external conversion step.
+ */
+INLINE static const char *io_get_input_field_alias(const char *name) {
+
+  if (strcmp(name, "SmoothingLength") == 0) return "SmoothingLengths";
+  if (strcmp(name, "InternalEnergy") == 0) return "InternalEnergies";
+  if (strcmp(name, "Density") == 0) return "Densities";
+
+  return NULL;
+}
+
 /**
  * @brief Constructs an #io_props from its parameters
  *

src/parallel_io.c

@@ -251,16 +251,40 @@ void read_array_parallel(hid_t grp, struct io_props props, size_t N,
                          long long N_total, int mpi_rank, long long offset,
                          const struct unit_system *internal_units,
                          const struct unit_system *ic_units, int cleanup_h,
-                         int cleanup_sqrt_a, double h, double a) {
+                         int cleanup_sqrt_a, double h, double a,
+                         const int accept_snapshot) {
 
   const size_t typeSize = io_sizeof_type(props.type);
   const size_t copySize = typeSize * props.dimension;
 
+  const char *dataset_name = props.name;
+
   /* Check whether the dataspace exists or not */
-  const htri_t exist = H5Lexists(grp, props.name, 0);
+  htri_t exist = H5Lexists(grp, dataset_name, 0);
   if (exist < 0) {
-    error("Error while checking the existence of data set '%s'.", props.name);
-  } else if (exist == 0) {
+    error("Error while checking the existence of data set '%s'.", dataset_name);
+  }
+
+  if (exist == 0) {
+    const char *alias = io_get_input_field_alias(props.name);
+    if (alias != NULL) {
+      const htri_t alias_exist = H5Lexists(grp, alias, 0);
+      if (alias_exist < 0) {
+        error("Error while checking the existence of data set '%s'.", alias);
+      } else if (alias_exist > 0 && accept_snapshot) {
+        dataset_name = alias;
+        exist = alias_exist;
+      } else if (alias_exist > 0 && props.importance == COMPULSORY) {
+        error(
+            "Compulsory data set '%s' not present in the file. Found snapshot "
+            "field '%s' instead. Set InitialConditions:accept_snapshot to 1 "
+            "to accept snapshot field names.",
+            props.name, alias);
+      }
+    }
+  }
+
+  if (exist == 0) {
     if (props.importance == COMPULSORY) {
       error("Compulsory data set '%s' not present in the file.", props.name);
     } else {
@@ -279,8 +303,8 @@ void read_array_parallel(hid_t grp, struct io_props props, size_t N,
   }
 
   /* Open data space in file */
-  const hid_t h_data = H5Dopen2(grp, props.name, H5P_DEFAULT);
-  if (h_data < 0) error("Error while opening data space '%s'.", props.name);
+  const hid_t h_data = H5Dopen2(grp, dataset_name, H5P_DEFAULT);
+  if (h_data < 0) error("Error while opening data space '%s'.", dataset_name);
 
 /* Parallel-HDF5 1.10.2 incorrectly reads data that was compressed */
 /* We detect this here and crash with an error message instead of  */
@@ -796,7 +820,8 @@ void read_ic_parallel(char *fileName, const struct unit_system *internal_units,
                       const int cleanup_sqrt_a, const double h, const double a,
                       const int mpi_rank, const int mpi_size, MPI_Comm comm,
                       MPI_Info info, const int n_threads, const int dry_run,
-                      const int remap_ids, struct ic_info *ics_metadata) {
+                      const int remap_ids, const int accept_snapshot,
+                      struct ic_info *ics_metadata) {
 
   hid_t h_file = 0, h_grp = 0;
   /* GADGET has only cubic boxes (in cosmological mode) */
@@ -1100,7 +1125,8 @@ void read_ic_parallel(char *fileName, const struct unit_system *internal_units,
         /* Read array. */
         read_array_parallel(h_grp, list[i], Nparticles, N_total[ptype],
                             mpi_rank, offset[ptype], internal_units, ic_units,
-                            cleanup_h, cleanup_sqrt_a, h, a);
+                            cleanup_h, cleanup_sqrt_a, h, a,
+                            accept_snapshot);
       }
 
     /* Close particle group */

src/parallel_io.h

@@ -47,7 +47,8 @@ void read_ic_parallel(char *fileName, const struct unit_system *internal_units,
                       const int cleanup_sqrt_a, const double h, const double a,
                       const int mpi_rank, const int mpi_size, MPI_Comm comm,
                       MPI_Info info, const int nr_threads, const int dry_run,
-                      const int remap_ids, struct ic_info *ics_metadata);
+                      const int remap_ids, const int accept_snapshot,
+                      struct ic_info *ics_metadata);
 
 void write_output_parallel(struct engine *e,
                            const struct unit_system *internal_units,

src/serial_io.c

@@ -89,17 +89,41 @@ void read_array_serial(hid_t grp, const struct io_props props, size_t N,
                        long long N_total, long long offset,
                        const struct unit_system *internal_units,
                        const struct unit_system *ic_units, int cleanup_h,
-                       int cleanup_sqrt_a, double h, double a) {
+                       int cleanup_sqrt_a, double h, double a,
+                       const int accept_snapshot) {
 
   const size_t typeSize = io_sizeof_type(props.type);
   const size_t copySize = typeSize * props.dimension;
   const size_t num_elements = N * props.dimension;
 
+  const char *dataset_name = props.name;
+
   /* Check whether the dataspace exists or not */
-  const htri_t exist = H5Lexists(grp, props.name, 0);
+  htri_t exist = H5Lexists(grp, dataset_name, 0);
   if (exist < 0) {
-    error("Error while checking the existence of data set '%s'.", props.name);
-  } else if (exist == 0) {
+    error("Error while checking the existence of data set '%s'.", dataset_name);
+  }
+
+  if (exist == 0) {
+    const char *alias = io_get_input_field_alias(props.name);
+    if (alias != NULL) {
+      const htri_t alias_exist = H5Lexists(grp, alias, 0);
+      if (alias_exist < 0) {
+        error("Error while checking the existence of data set '%s'.", alias);
+      } else if (alias_exist > 0 && accept_snapshot) {
+        dataset_name = alias;
+        exist = alias_exist;
+      } else if (alias_exist > 0 && props.importance == COMPULSORY) {
+        error(
+            "Compulsory data set '%s' not present in the file. Found snapshot "
+            "field '%s' instead. Set InitialConditions:accept_snapshot to 1 "
+            "to accept snapshot field names.",
+            props.name, alias);
+      }
+    }
+  }
+
+  if (exist == 0) {
     if (props.importance == COMPULSORY) {
       error("Compulsory data set '%s' not present in the file.", props.name);
     } else {
@@ -122,8 +146,8 @@ void read_array_serial(hid_t grp, const struct io_props props, size_t N,
   /* fflush(stdout); */
 
   /* Open data space */
-  const hid_t h_data = H5Dopen(grp, props.name, H5P_DEFAULT);
-  if (h_data < 0) error("Error while opening data space '%s'.", props.name);
+  const hid_t h_data = H5Dopen(grp, dataset_name, H5P_DEFAULT);
+  if (h_data < 0) error("Error while opening data space '%s'.", dataset_name);
 
   /* Allocate temporary buffer */
   void *temp = malloc(num_elements * typeSize);
@@ -158,7 +182,7 @@ void read_array_serial(hid_t grp, const struct io_props props, size_t N,
   /* Using HDF5 dataspaces would be better */
   const hid_t h_err = H5Dread(h_data, io_hdf5_type(props.type), h_memspace,
                               h_filespace, H5P_DEFAULT, temp);
-  if (h_err < 0) error("Error while reading data array '%s'.", props.name);
+  if (h_err < 0) error("Error while reading data array '%s'.", dataset_name);
 
   /* Unit conversion if necessary */
   const double factor =
@@ -569,7 +593,8 @@ void read_ic_serial(char *fileName, const struct unit_system *internal_units,
                     const int cleanup_sqrt_a, double h, double a,
                     const int mpi_rank, int mpi_size, MPI_Comm comm,
                     MPI_Info info, const int n_threads, const int dry_run,
-                    const int remap_ids, struct ic_info *ics_metadata) {
+                    const int remap_ids, const int accept_snapshot,
+                    struct ic_info *ics_metadata) {
 
   hid_t h_file = 0, h_grp = 0;
   /* GADGET has only cubic boxes (in cosmological mode) */
@@ -905,7 +930,8 @@ void read_ic_serial(char *fileName, const struct unit_system *internal_units,
             /* Read array. */
             read_array_serial(h_grp, list[i], Nparticles, N_total[ptype],
                               offset[ptype], internal_units, ic_units,
-                              cleanup_h, cleanup_sqrt_a, h, a);
+                              cleanup_h, cleanup_sqrt_a, h, a,
+                              accept_snapshot);
           }
 
         /* Close particle group */

src/serial_io.h

@@ -49,7 +49,8 @@ void read_ic_serial(char *fileName, const struct unit_system *internal_units,
                     const int cleanup_sqrt_a, const double h, const double a,
                     const int mpi_rank, int mpi_size, MPI_Comm comm,
                     MPI_Info info, const int n_threads, const int dry_run,
-                    const int remap_ids, struct ic_info *ics_metadata);
+                    const int remap_ids, const int accept_snapshot,
+                    struct ic_info *ics_metadata);
 
 void write_output_serial(struct engine *e,
                          const struct unit_system *internal_units,

src/single_io.c

@@ -86,17 +86,41 @@ static const int io_max_size_output_list = 100;
 void read_array_single(hid_t h_grp, const struct io_props props, size_t N,
                        const struct unit_system *internal_units,
                        const struct unit_system *ic_units, int cleanup_h,
-                       int cleanup_sqrt_a, double h, double a) {
+                       int cleanup_sqrt_a, double h, double a,
+                       const int accept_snapshot) {
 
   const size_t typeSize = io_sizeof_type(props.type);
   const size_t copySize = typeSize * props.dimension;
   const size_t num_elements = N * props.dimension;
 
+  const char *dataset_name = props.name;
+
   /* Check whether the dataspace exists or not */
-  const htri_t exist = H5Lexists(h_grp, props.name, 0);
+  htri_t exist = H5Lexists(h_grp, dataset_name, 0);
   if (exist < 0) {
-    error("Error while checking the existence of data set '%s'.", props.name);
-  } else if (exist == 0) {
+    error("Error while checking the existence of data set '%s'.", dataset_name);
+  }
+
+  if (exist == 0) {
+    const char *alias = io_get_input_field_alias(props.name);
+    if (alias != NULL) {
+      const htri_t alias_exist = H5Lexists(h_grp, alias, 0);
+      if (alias_exist < 0) {
+        error("Error while checking the existence of data set '%s'.", alias);
+      } else if (alias_exist > 0 && accept_snapshot) {
+        dataset_name = alias;
+        exist = alias_exist;
+      } else if (alias_exist > 0 && props.importance == COMPULSORY) {
+        error(
+            "Compulsory data set '%s' not present in the file. Found snapshot "
+            "field '%s' instead. Set InitialConditions:accept_snapshot to 1 "
+            "to accept snapshot field names.",
+            props.name, alias);
+      }
+    }
+  }
+
+  if (exist == 0) {
     if (props.importance == COMPULSORY) {
       error("Compulsory data set '%s' not present in the file.", props.name);
     } else {
@@ -119,8 +143,8 @@ void read_array_single(hid_t h_grp, const struct io_props props, size_t N,
   /*         props.name); */
 
   /* Open data space */
-  const hid_t h_data = H5Dopen(h_grp, props.name, H5P_DEFAULT);
-  if (h_data < 0) error("Error while opening data space '%s'.", props.name);
+  const hid_t h_data = H5Dopen(h_grp, dataset_name, H5P_DEFAULT);
+  if (h_data < 0) error("Error while opening data space '%s'.", dataset_name);
 
   /* Allocate temporary buffer */
   void *temp = malloc(num_elements * typeSize);
@@ -131,7 +155,7 @@ void read_array_single(hid_t h_grp, const struct io_props props, size_t N,
   /* Using HDF5 dataspaces would be better */
   const hid_t h_err = H5Dread(h_data, io_hdf5_type(props.type), H5S_ALL,
                               H5S_ALL, H5P_DEFAULT, temp);
-  if (h_err < 0) error("Error while reading data array '%s'.", props.name);
+  if (h_err < 0) error("Error while reading data array '%s'.", dataset_name);
 
   /* Unit conversion if necessary */
   const double unit_factor =
@@ -466,7 +490,7 @@ void read_ic_single(
     const int with_stars, const int with_black_holes, const int with_cosmology,
     const int cleanup_h, const int cleanup_sqrt_a, const double h,
     const double a, const int n_threads, const int dry_run, const int remap_ids,
-    struct ic_info *ics_metadata) {
+    const int accept_snapshot, struct ic_info *ics_metadata) {
 
   hid_t h_file = 0, h_grp = 0;
   /* GADGET has only cubic boxes (in cosmological mode) */
@@ -754,7 +778,7 @@ void read_ic_single(
 
         /* Read array. */
         read_array_single(h_grp, list[i], Nparticles, internal_units, ic_units,
-                          cleanup_h, cleanup_sqrt_a, h, a);
+                          cleanup_h, cleanup_sqrt_a, h, a, accept_snapshot);
       }
 
     /* Close particle group */

src/single_io.h

@@ -41,7 +41,8 @@ void read_ic_single(
     const int with_stars, const int with_black_holes, const int with_cosmology,
     const int cleanup_h, const int cleanup_sqrt_a, const double h,
     const double a, const int nr_threads, const int dry_run,
-    const int remap_ids, struct ic_info *ics_metadata);
+    const int remap_ids, const int accept_snapshot,
+    struct ic_info *ics_metadata);
 
 void write_output_single(struct engine *e,
                          const struct unit_system *internal_units,

swift.c

@@ -1095,6 +1095,8 @@ int main(int argc, char *argv[]) {
         params, "InitialConditions:generate_gas_in_ics", 0);
     const int remap_ids =
         parser_get_opt_param_int(params, "InitialConditions:remap_ids", 0);
+    const int accept_snapshot =
+        parser_get_opt_param_int(params, "InitialConditions:accept_snapshot", 0);
 
     /* Initialise the cosmology */
     if (with_cosmology)
@@ -1281,23 +1283,25 @@ int main(int argc, char *argv[]) {
                      with_gravity, with_sinks, with_stars, with_black_holes,
                      with_cosmology, cleanup_h, cleanup_sqrt_a, cosmo.h,
                      cosmo.a, myrank, nr_nodes, MPI_COMM_WORLD, MPI_INFO_NULL,
-                     nr_threads, dry_run, remap_ids, &ics_metadata);
+                     nr_threads, dry_run, remap_ids, accept_snapshot,
+                     &ics_metadata);
 #else
     read_ic_serial(ICfileName, &us, dim, &parts, &gparts, &sinks, &sparts,
                    &bparts, &Ngas, &Ngpart, &Ngpart_background, &Nnupart,
                    &Nsink, &Nspart, &Nbpart, &flag_entropy_ICs, with_hydro,
                    with_gravity, with_sinks, with_stars, with_black_holes,
                    with_cosmology, cleanup_h, cleanup_sqrt_a, cosmo.h, cosmo.a,
                    myrank, nr_nodes, MPI_COMM_WORLD, MPI_INFO_NULL, nr_threads,
-                   dry_run, remap_ids, &ics_metadata);
+                   dry_run, remap_ids, accept_snapshot, &ics_metadata);
 #endif
 #else
     read_ic_single(ICfileName, &us, dim, &parts, &gparts, &sinks, &sparts,
                    &bparts, &Ngas, &Ngpart, &Ngpart_background, &Nnupart,
                    &Nsink, &Nspart, &Nbpart, &flag_entropy_ICs, with_hydro,
                    with_gravity, with_sinks, with_stars, with_black_holes,
                    with_cosmology, cleanup_h, cleanup_sqrt_a, cosmo.h, cosmo.a,
-                   nr_threads, dry_run, remap_ids, &ics_metadata);
+                   nr_threads, dry_run, remap_ids, accept_snapshot,
+                   &ics_metadata);
 #endif
 #endif