ENH: fix compatibility issues with newest versions of SWIFT (#4921)

yt/frontends/swift/data_structures.py

@@ -2,11 +2,12 @@
 
 from yt.data_objects.static_output import ParticleFile
 from yt.frontends.sph.data_structures import SPHDataset, SPHParticleIndex
-from yt.frontends.sph.fields import SPHFieldInfo
 from yt.funcs import only_on_root
 from yt.utilities.logger import ytLogger as mylog
 from yt.utilities.on_demand_imports import _h5py as h5py
 
+from .fields import SwiftFieldInfo
+
 
 class SwiftParticleFile(ParticleFile):
     pass
@@ -15,7 +16,7 @@ class SwiftParticleFile(ParticleFile):
 class SwiftDataset(SPHDataset):
     _load_requirements = ["h5py"]
     _index_class = SPHParticleIndex
-    _field_info_class = SPHFieldInfo
+    _field_info_class = SwiftFieldInfo
     _file_class = SwiftParticleFile
 
     _particle_mass_name = "Masses"
@@ -97,7 +98,15 @@ def _parse_parameter_file(self):
         # Read from the HDF5 file, this gives us all the info we need. The rest
         # of this function is just parsing.
         header = self._get_info_attributes("Header")
-        runtime_parameters = self._get_info_attributes("RuntimePars")
+        # RuntimePars were removed from snapshots at SWIFT commit 6271388
+        # between SWIFT versions 0.8.5 and 0.9.0
+        with h5py.File(self.filename, mode="r") as handle:
+            has_runtime_pars = "RuntimePars" in handle.keys()
+
+        if has_runtime_pars:
+            runtime_parameters = self._get_info_attributes("RuntimePars")
+        else:
+            runtime_parameters = {}
 
         policy = self._get_info_attributes("Policy")
         # These are the parameterfile parameters from *.yml at runtime
@@ -113,7 +122,10 @@ def _parse_parameter_file(self):
         self.dimensionality = int(header["Dimension"])
 
         # SWIFT is either all periodic, or not periodic at all
-        periodic = int(runtime_parameters["PeriodicBoundariesOn"])
+        if has_runtime_pars:
+            periodic = int(runtime_parameters["PeriodicBoundariesOn"])
+        else:
+            periodic = int(parameters["InitialConditions:periodic"])
 
         if periodic:
             self._periodicity = [True] * self.dimensionality
@@ -131,7 +143,14 @@ def _parse_parameter_file(self):
                 self.current_redshift = float(header["Redshift"])
                 # These won't be present if self.cosmological_simulation is false
                 self.omega_lambda = float(parameters["Cosmology:Omega_lambda"])
-                self.omega_matter = float(parameters["Cosmology:Omega_m"])
+                # Cosmology:Omega_m parameter deprecated at SWIFT commit d2783c2
+                # Between SWIFT versions 0.9.0 and 1.0.0
+                if "Cosmology:Omega_cdm" in parameters:
+                    self.omega_matter = float(parameters["Cosmology:Omega_b"]) + float(
+                        parameters["Cosmology:Omega_cdm"]
+                    )
+                else:
+                    self.omega_matter = float(parameters["Cosmology:Omega_m"])
                 # This is "little h"
                 self.hubble_constant = float(parameters["Cosmology:h"])
             except KeyError:
@@ -155,9 +174,10 @@ def _parse_parameter_file(self):
         # Store the un-parsed information should people want it.
         self.parameters = {
             "header": header,
-            "runtime_parameters": runtime_parameters,
             "policy": policy,
             "parameters": parameters,
+            # NOTE: runtime_parameters may be empty
+            "runtime_parameters": runtime_parameters,
             "hydro": hydro,
             "subgrid": subgrid,
         }

yt/frontends/swift/fields.py

@@ -0,0 +1,27 @@
+from yt.frontends.sph.fields import SPHFieldInfo
+
+
+class SwiftFieldInfo(SPHFieldInfo):
+    def __init__(self, ds, field_list, slice_info=None):
+        self.known_particle_fields += (
+            (
+                "InternalEnergies",
+                ("code_specific_energy", ["specific_thermal_energy"], None),
+            ),
+            ("Densities", ("code_mass / code_length**3", ["density"], None)),
+            ("SmoothingLengths", ("code_length", ["smoothing_length"], None)),
+        )
+        super().__init__(ds, field_list, slice_info)
+
+    def setup_particle_fields(self, ptype, *args, **kwargs):
+        super().setup_particle_fields(ptype, *args, **kwargs)
+
+        if ptype in ("PartType0", "Gas"):
+            self.setup_gas_particle_fields(ptype)
+
+    def setup_gas_particle_fields(self, ptype):
+        self.alias((ptype, "temperature"), (ptype, "Temperatures"))
+        self.alias(("gas", "temperature"), (ptype, "Temperatures"))
+
+        for ax in ("x", "y", "z"):
+            self.alias((ptype, ax), (ptype, "particle_position_" + ax))

yt/frontends/swift/io.py

@@ -65,8 +65,14 @@ def _get_smoothing_length(self, sub_file, pdtype=None, pshape=None):
         with h5py.File(sub_file.filename, mode="r") as f:
             pcount = f["/Header"].attrs["NumPart_ThisFile"][ind].astype("int64")
             pcount = np.clip(pcount - si, 0, ei - si)
+            keys = f[ptype].keys()
+            # SWIFT commit a94cc81 changed from "SmoothingLength" to "SmoothingLengths"
+            # between SWIFT versions 0.8.2 and 0.8.3
+            if "SmoothingLengths" in keys:
+                hsml = f[ptype]["SmoothingLengths"][si:ei, ...]
+            else:
+                hsml = f[ptype]["SmoothingLength"][si:ei, ...]
             # we upscale to float64
-            hsml = f[ptype]["SmoothingLength"][si:ei, ...]
             hsml = hsml.astype("float64", copy=False)
             return hsml