ENH: add global meta data

bilby/core/sampler/__init__.py

@@ -7,6 +7,7 @@
     command_line_args,
     env_package_list,
     get_entry_points,
+    global_meta_data,
     loaded_modules_dict,
     logger,
 )
@@ -251,6 +252,7 @@ def run_sampler(
     meta_data["likelihood"] = likelihood.meta_data
     meta_data["loaded_modules"] = loaded_modules_dict()
     meta_data["environment_packages"] = env_package_list(as_dataframe=True)
+    meta_data["global_meta_data"] = global_meta_data
 
     if command_line_args.bilby_zero_likelihood_mode:
         from bilby.core.likelihood import ZeroLikelihood

bilby/core/utils/__init__.py

@@ -10,6 +10,7 @@
 from .introspection import *
 from .io import *
 from .log import *
+from .meta_data import *
 from .plotting import *
 from .samples import *
 from .series import *

bilby/core/utils/meta_data.py

@@ -0,0 +1,25 @@
+from collections import UserDict
+
+from . import random
+
+
+class GlobalMetaData(UserDict):
+    """A class to store global meta data.
+
+    This class is a singleton, meaning that only one instance can exist at a time.
+    """
+
+    _instance = None
+
+    def add_to_meta_data(self, key, value):
+        self[key] = value
+
+    def __new__(cls, *args, **kwargs):
+        if cls._instance is None:
+            cls._instance = super().__new__(cls)
+        return cls._instance
+
+
+global_meta_data = GlobalMetaData({
+    "rng": random.rng
+})

bilby/core/utils/random.py

@@ -11,7 +11,11 @@ class Generator:
 
 
 def seed(seed):
+    from .meta_data import global_meta_data
+
     Generator.rng = default_rng(seed)
+    global_meta_data.add_to_meta_data("rng", Generator.rng)
+    global_meta_data.add_to_meta_data("seed", seed)
 
 
 def generate_seeds(nseeds):

bilby/gw/cosmology.py

@@ -8,10 +8,12 @@
 
 def _set_default_cosmology():
     from astropy import cosmology as cosmo
+    from ..core.utils.meta_data import global_meta_data
     global DEFAULT_COSMOLOGY, COSMOLOGY
     if DEFAULT_COSMOLOGY is None:
         DEFAULT_COSMOLOGY = cosmo.Planck15
         COSMOLOGY = [DEFAULT_COSMOLOGY, DEFAULT_COSMOLOGY.name]
+        global_meta_data.add_to_meta_data("cosmology", COSMOLOGY)
 
 
 def get_available_cosmologies():