diff --git a/logger/examples/reader_example.py b/logger/examples/reader_example.py
index f75d438347f277e8cb86c90501b55b8a75538309..6fe65399cc70de43b6638820c19f41486ee2d9df 100644
--- a/logger/examples/reader_example.py
+++ b/logger/examples/reader_example.py
@@ -47,9 +47,17 @@ print("basename: %s" % basename)
print("time: %g" % time)
# read the logger
+gas_type = 0
with logger.Reader(basename, verbose=0) as reader:
t = reader.get_time_limits()
- pos, ent = reader.get_particle_data(["Coordinates", "Entropies"], time)
+
+ fields = reader.get_list_fields(gas_type)
+ if ("Coordinates" not in fields or
+ "Entropies" not in fields):
+ raise Exception("Field not found in the logfile")
+
+ pos, ent = reader.get_particle_data(
+ ["Coordinates", "Entropies"], time, gas_type)
print("Min/Max of the position:", pos.min(), pos.max())
print("Min/Max of the entropy:", ent.min(), ent.max())
diff --git a/logger/logger_python_wrapper.c b/logger/logger_python_wrapper.c
index 7278a5f357e213a43d220f06022a85970e9c22a4..9c7336dacd09e868cab2f879a398f38e2ec6a4bd 100644
--- a/logger/logger_python_wrapper.c
+++ b/logger/logger_python_wrapper.c
@@ -272,6 +272,138 @@ static PyObject *pyExit(__attribute__((unused)) PyObject *self,
Py_RETURN_NONE;
}
+
+static PyObject *pyGetListFields(__attribute__((unused)) PyObject *self,
+ PyObject *args) {
+ PyObjectReader *self_reader = (PyObjectReader *)self;
+ if (!self_reader->ready) {
+ error_python(
+ "The logger is not ready yet."
+ "Did you forget to open it with \"with\"?");
+ }
+
+ /* input variables. */
+ PyObject *types = Py_None;
+
+ /* parse the arguments. */
+ if (!PyArg_ParseTuple(args, "|O", &types)) return NULL;
+
+ /* Get the type of particles to read. */
+ int read_types[swift_type_count] = {0};
+ /* By default, we read everything */
+ if (types == Py_None) {
+ for (int i = 0; i < swift_type_count; i++) {
+ read_types[i] = 1;
+ }
+ }
+ /* Deal with the case of a single int. */
+ else if (PyLong_Check(types)) {
+ const size_t type = PyLong_AsSize_t(types);
+ if (type >= swift_type_count) {
+ error_python("Unexpected particle type %zi", type);
+ }
+ read_types[type] = 1;
+ }
+ /* Deal with the case of a list */
+ else if (PyList_Check(types)) {
+ const size_t size = PyList_Size(types);
+ for (size_t i = 0; i < size; i++) {
+ PyObject *cur = PyList_GetItem(types, i);
+ const size_t type = PyLong_AsSize_t(cur);
+ if (type >= swift_type_count) {
+ error_python("Unexpected particle type %zi", type);
+ }
+ read_types[type] = 1;
+ }
+ }
+
+ /* initialize the reader. */
+ struct logger_reader *reader = &self_reader->reader;
+ const struct header *h = &reader->log.header;
+
+ /* Create the array to check if a field is present. */
+ int *field_present = (int *)malloc(h->masks_count * sizeof(int));
+ if (field_present == NULL) {
+ error("Failed to allocate the memory for the fields present.");
+ }
+
+ /* Initialize the array */
+ for (int i = 0; i < h->masks_count; i++) {
+ field_present[i] = 1;
+ }
+
+ /* Check all the fields */
+ for (int i = 0; i < swift_type_count; i++) {
+ /* Skip the types that are not required */
+ if (read_types[i] == 0) continue;
+
+ /* Get the list of fields for each particle types. */
+ const char **field_names = NULL;
+ int number_fields = -1;
+ switch (i) {
+ case swift_type_gas:
+ number_fields = hydro_logger_field_count;
+ field_names = hydro_logger_field_names;
+ break;
+
+ case swift_type_dark_matter:
+ case swift_type_dark_matter_background:
+ number_fields = gravity_logger_field_count;
+ field_names = gravity_logger_field_names;
+ break;
+
+ case swift_type_stars:
+ number_fields = stars_logger_field_count;
+ field_names = stars_logger_field_names;
+ break;
+
+ default:
+ message("Particle type %i not implemented, skipping it", i);
+ continue;
+ }
+
+ for (int j = 0; j < h->masks_count; j++) {
+ /* Skip the fields not found in previous type. */
+ if (field_present[j] == 0) continue;
+
+ /* Check if the field is present */
+ int found = 0;
+ for (int k = 0; k < number_fields; k++) {
+ if (strcmp(h->masks[j].name, field_names[k]) == 0) {
+ found = 1;
+ break;
+ }
+ }
+
+ /* Set the field as not found */
+ if (!found) field_present[j] = 0;
+ }
+ }
+
+ /* Count the number of fields found */
+ int number_fields = 0;
+ for (int i = 0; i < h->masks_count; i++) {
+ number_fields += field_present[i];
+ }
+
+ /* Create the python list for the output*/
+ PyObject *list = PyList_New(number_fields);
+ int current = 0;
+ for (int i = 0; i < h->masks_count; i++) {
+ /* Keep only the field present. */
+ if (field_present[i] == 0) continue;
+
+ PyObject *name = PyUnicode_FromString(h->masks[i].name);
+ PyList_SetItem(list, current, name);
+ current += 1;
+ }
+
+ /* Free the memory. */
+ free(field_present);
+
+ return list;
+}
+
/**
* @brief Read some fields at a given time.
*
@@ -391,9 +523,20 @@ static PyMethodDef libloggerReaderMethods[] = {
" The list of fields (e.g. 'Coordinates', 'Entropies', ...)\n\n"
"time: float\n"
" The time at which the fields must be read.\n\n"
+ "Returns\n"
"-------\n\n"
"list_of_fields: list\n"
" Each element is a numpy array containing the corresponding field.\n"},
+ {"get_list_fields", pyGetListFields, METH_VARARGS,
+ "Read the list of available fields in the logfile.\n\n"
+ "Parameters\n"
+ "----------\n\n"
+ "type: int, list\n"
+ " The particle type for the list of fields\n\n"
+ "Returns\n"
+ "-------\n"
+ "fields: tuple\n"
+ " The list of fields present in the logfile.\n"},
{"__enter__", pyEnter, METH_VARARGS, ""},
{"__exit__", pyExit, METH_VARARGS, ""},
{NULL, NULL, 0, NULL} /* Sentinel */
@@ -438,6 +581,10 @@ static PyTypeObject PyObjectReader_Type = {
">>> import liblogger as logger\n"
">>> with logger.Reader(\"index_0000\") as reader:\n"
">>> t0, t1 = reader.get_time_limits()\n"
+ ">>> fields = reader.get_list_fields()\n"
+ ">>> if \"Coordinates\" not in fields:\n"
+ ">>> raise Exception(\"Field Coordinates not present in the "
+ "logfile.\")\n"
">>> pos, ent = reader.get_particle_data([\"Coordinates\", "
"\"Entropies\"]"
", 0.5 * (t0 + t1))\n",