Allow snapshots and restarts to be reused directly

Author: Francyrad

examples/parameter_example.yml

@@ -240,6 +240,7 @@ InitialConditions:
 
 # Parameters controlling restarts
 Restarts:
+  restart:           0          # (Optional) whether to continue from existing restart files. Equivalent to passing --restart on the command line.
   enable:             1          # (Optional) whether to enable dumping restarts at fixed intervals.
   save:               1          # (Optional) whether to save copies of the previous set of restart files (named .prev)
   onexit:             0          # (Optional) whether to dump restarts on exit (*needs enable*)

src/engine_config.c

@@ -234,6 +234,41 @@ void engine_config(int restart, int fof, struct engine *e,
   /* Welcome message */
   if (e->nodeID == 0) message("Running simulation '%s'.", e->run_name);
 
+  /* Values that are safe to change between restart cycles. The integer
+   * timeline itself is not changed here; it is part of the restart state. */
+  if (restart && !fof) {
+    if (!(e->policy & engine_policy_cosmology)) {
+      const double time_begin =
+          parser_get_param_double(params, "TimeIntegration:time_begin");
+      const double time_end =
+          parser_get_param_double(params, "TimeIntegration:time_end");
+
+      if (time_begin != e->time_begin || time_end != e->time_end) {
+        if (e->nodeID == 0)
+          message(
+              "WARNING: ignoring changed TimeIntegration:time_begin/time_end "
+              "on restart; the saved integer timeline is preserved.");
+      }
+    }
+
+    e->dt_min = parser_get_param_double(params, "TimeIntegration:dt_min");
+    e->dt_max = parser_get_param_double(params, "TimeIntegration:dt_max");
+
+    e->a_first_snapshot = parser_get_opt_param_double(
+        params, "Snapshots:scale_factor_first", e->a_first_snapshot);
+    e->time_first_snapshot = parser_get_opt_param_double(
+        params, "Snapshots:time_first", e->time_first_snapshot);
+    e->delta_time_snapshot = parser_get_opt_param_double(
+        params, "Snapshots:delta_time", e->delta_time_snapshot);
+
+    e->a_first_statistics = parser_get_opt_param_double(
+        params, "Statistics:scale_factor_first", e->a_first_statistics);
+    e->time_first_statistics = parser_get_opt_param_double(
+        params, "Statistics:time_first", e->time_first_statistics);
+    e->delta_time_statistics =
+        parser_get_param_double(params, "Statistics:delta_time");
+  }
+
   /* Check-pointing properties */
 
   e->restart_stop_steps =

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

@@ -256,11 +256,28 @@ void read_array_parallel(hid_t grp, struct io_props props, size_t N,
   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) {
+        dataset_name = alias;
+        exist = alias_exist;
+      }
+    }
+  }
+
+  if (exist == 0) {
     if (props.importance == COMPULSORY) {
       error("Compulsory data set '%s' not present in the file.", props.name);
     } else {
@@ -279,8 +296,8 @@ 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  */

src/serial_io.c

@@ -95,11 +95,28 @@ void read_array_serial(hid_t grp, const struct io_props props, size_t N,
   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) {
+        dataset_name = alias;
+        exist = alias_exist;
+      }
+    }
+  }
+
+  if (exist == 0) {
     if (props.importance == COMPULSORY) {
       error("Compulsory data set '%s' not present in the file.", props.name);
     } else {
@@ -122,8 +139,8 @@ 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 +175,7 @@ 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 =

src/single_io.c

@@ -92,11 +92,28 @@ void read_array_single(hid_t h_grp, const struct io_props props, size_t N,
   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) {
+        dataset_name = alias;
+        exist = alias_exist;
+      }
+    }
+  }
+
+  if (exist == 0) {
     if (props.importance == COMPULSORY) {
       error("Compulsory data set '%s' not present in the file.", props.name);
     } else {
@@ -119,8 +136,8 @@ 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 +148,7 @@ 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 =

swift.c

@@ -843,6 +843,14 @@ int main(int argc, char *argv[]) {
   MPI_Bcast(params, sizeof(struct swift_params), MPI_BYTE, 0, MPI_COMM_WORLD);
 #endif
 
+  /* Allow restarts to be requested directly from the parameter file. */
+  const int restart_from_params =
+      parser_get_opt_param_int(params, "Restarts:restart", 0);
+  if (restart_from_params) {
+    if (myrank == 0) message("Restart requested by parameter file.");
+    restart = 1;
+  }
+
   /* Read the provided output selection file, if available. Best to
    * do this after broadcasting the parameters as there may be code in this
    * function that is repeated on each node based on the parameter file. */