add loader for osyris

src/galaxy_ninja/loaders/load_data_osyris.py

@@ -0,0 +1,55 @@
+# coding: utf-8
+
+import numpy as np
+import osyris
+
+
+def load_fields_osyris(path="", snap_id=0, data=None):
+    """
+    Returns
+    -------
+    dict
+        A dataset of cells in the following format:
+        gas:
+            position (Ngas, 3) [kpc], centered
+            volume   (Ngas)    [pc^3]
+            velocity (Ngas, 3) [km/s]
+            mass     (Ngas)    [Msun]
+        stars:
+            position (Nstar, 3) [kpc], centered
+            velocity (Nstar, 3) [km/s]
+            mass     (Nstar)    [Msun]
+            birth_time      (Nstar)    [Myr]
+        dm:
+            position (Ngas, 3) [kpc], centered
+            velocity (Ngas, 3) [km/s]
+            mass     (Ngas)    [Msun]
+        maps:
+            extent      (xmin, xmax, ymin, ymax) Coordinates of the edges of the map, centered
+            gas_coldens (Nx, Ny) [Msun/pc^2], map of column density
+    """
+
+    if data is None:
+        data = osyris.RamsesDataset(snap_id, path=path).load(select=["mesh", "part"])
+    
+    
+    time = data.meta["time"].to("Myr").magnitude
+    boxlen = data.meta["boxlen"] * data.units["x"].to("kpc")
+    
+    gas = data["mesh"]
+    center = osyris.Vector(x=500, y=500, z=500, unit="pc")
+    
+    # Create dataset
+    data = {
+        "header": {"time": time, 
+                   "fluids": ["gas"],
+                   "box_size": boxlen },
+        "gas": {
+            "position": (gas["position"] - center).to("kpc").values,
+            "volume": (gas["dx"]**3).to("pc^3").values,
+            "velocity": gas["velocity"].to("km/s").values,
+            "mass": (gas["density"] * gas["dx"]**3).to("M_sun").values
+        },
+    }
+    return data
+