make setup env private

mess/__init__.py

@@ -1,4 +1,12 @@
 # Copyright (c) 2024 Graphcore Ltd. All rights reserved.
+"""MESS: Modern Electronic Structure Simulations
+
+The mess simulation environment can be customised by setting the following environment
+variables:
+  * ``MESS_ENABLE_FP64``: enables float64 precision. Defaults to ``True``.
+  * ``MESS_CACHE_DIR``: JIT compilation cache location. Defaults to ``~/.cache/mess``
+"""
+
 import importlib.metadata
 
 __version__ = importlib.metadata.version("mess")
@@ -10,14 +18,7 @@
 __all__ = ["molecule", "Hamiltonian", "minimise", "basisset"]
 
 
-def setup_env():
-    """Setup the environment for MESS
-
-    This can be customised by setting the environment variables:
-
-      MESS_ENABLE_FP64: enables float64 precision. Defaults to True.
-      MESS_CACHE_DIR: JIT compilation cache location. Defaults to ~/.cache/mess
-    """
+def _setup_env():
     import os
     import os.path as osp
 
@@ -31,4 +32,4 @@ def setup_env():
     cc.set_cache_dir(cache_dir)
 
 
-setup_env()
+_setup_env()