Address code reviews

Co-authored-by: Diego Ferigo <diego.ferigo@iit.it>

src/jaxsim/__init__.py

@@ -11,34 +11,32 @@ def _jnp_options() -> None:
     # Check if running on TPU
     is_tpu = jax.devices()[0].platform == "tpu"
 
-    # Determine if 64-bit precision is requested
+    # Enable by default 64-bit precision to get accurate physics.
+    # Users can enforce 32-bit precision by setting the following variable to 0.
     use_x64 = os.environ.get("JAX_ENABLE_X64", "1") != "0"
 
-    # Raise an error if 64-bit precision is not allowed on TPU
+    # Notify the user if unsupported 64-bit precision was enforced on TPU.
     if is_tpu and use_x64:
         msg = "64-bit precision is not allowed on TPU. Enforcing 32bit precision."
-        logging.error(msg)
+        logging.warning(msg)
+        use_x64 = False
 
-    # Enable 64-bit precision in JAX
-    elif not is_tpu and use_x64:
-        logging.info("Enabling JAX to use 64bit precision")
+    # Enable 64-bit precision in JAX.
+    if use_x64:
+        logging.info("Enabling JAX to use 64-bit precision")
         jax.config.update("jax_enable_x64", True)
 
         import jax.numpy as jnp
         import numpy as np
 
-        # Verify 64-bit precision is correctly set
+        # Verify that 64-bit precision is correctly set.
         if jnp.empty(0, dtype=float).dtype != jnp.empty(0, dtype=np.float64).dtype:
-            logging.warning("Failed to enable 64bit precision in JAX")
+            logging.warning("Failed to enable 64-bit precision in JAX")
 
-    # Enforce 32-bit precision on TPU
-    elif is_tpu:
-        logging.warning("JAX is running on TPU; 32bit precision is enforced.")
-
-    # Warn about experimental use of 32-bit precision
+    # Warn about experimental usage of 32-bit precision.
     else:
         logging.warning(
-            "Using 32bit precision in JaxSim is still experimental, please avoid to use variable step integrators."
+            "Using 32-bit precision in JaxSim is still experimental, please avoid to use variable step integrators."
         )