[random] deprecate named key creation functions

CHANGELOG.md

@@ -10,6 +10,11 @@ Remember to align the itemized text with the first line of an item within a list
 
 * Deprecations
   * Removed the deprecated module `jax.abstract_arrays` and all its contents.
+  * Named key constructors in {mod}`jax.random` are deprecated. Pass the `impl` argument
+    to {func}`jax.random.PRNGKey` or {func}`jax.random.key` instead:
+    * `random.threefry2x32_key(seed)` becomes `random.PRNGKey(seed, impl='threefry2x32')`
+    * `random.rbg_key(seed)` becomes `random.PRNGKey(seed, impl='rbg')`
+    * `random.unsafe_rbg_key(seed)` becomes `random.PRNGKey(seed, impl='unsafe_rbg')`
 
 # jaxlib 0.4.17
 

jax/_src/random.py

@@ -195,8 +195,8 @@ def _check_default_impl_with_no_custom_prng(impl, name):
   default_name = config.jax_default_prng_impl
   if not config.jax_enable_custom_prng and default_impl is not impl:
     raise RuntimeError('jax_enable_custom_prng must be enabled in order '
-                       f'to seed an RNG with an implementation "f{name}" '
-                       f'differing from the default "f{default_name}".')
+                       f'to seed an RNG with an implementation "{name}" '
+                       f'differing from the default "{default_name}".')
 
 def threefry2x32_key(seed: int) -> KeyArray:
   """Creates a threefry2x32 PRNG key from an integer seed."""

jax/random.py

@@ -170,17 +170,17 @@
   randint as randint,
   random_gamma_p as random_gamma_p,
   rayleigh as rayleigh,
-  rbg_key as rbg_key,
+  rbg_key as _deprecated_rbg_key,
   shuffle as shuffle,
   split as split,
   t as t,
   threefry_2x32 as threefry_2x32,
-  threefry2x32_key as threefry2x32_key,
+  threefry2x32_key as _deprecated_threefry2x32_key,
   threefry2x32_p as threefry2x32_p,
   triangular as triangular,
   truncated_normal as truncated_normal,
   uniform as uniform,
-  unsafe_rbg_key as unsafe_rbg_key,
+  unsafe_rbg_key as _deprecated_unsafe_rbg_key,
   wald as wald,
   weibull_min as weibull_min,
   wrap_key_data as wrap_key_data,
@@ -202,12 +202,25 @@
         "jax.dtypes.issubdtype(arr, jax.dtypes.prng_key) for runtime detection of "
         "typed prng keys.", _PRNGKeyArray
     ),
+    # Added September 21, 2023
+    "threefry2x32_key": (
+        "jax.random.threefry2x32_key(seed) is deprecated. "
+        "Use jax.random.PRNGKey(seed, 'threefry2x32')", _deprecated_threefry2x32_key),
+    "rbg_key": (
+        "jax.random.rbg_key(seed) is deprecated. "
+        "Use jax.random.PRNGKey(seed, 'rbg')", _deprecated_rbg_key),
+    "unsafe_rbg_key": (
+        "jax.random.unsafe_rbg_key(seed) is deprecated. "
+        "Use jax.random.PRNGKey(seed, 'unsafe_rbg')", _deprecated_unsafe_rbg_key),
 }
 
 import typing
 if typing.TYPE_CHECKING:
   PRNGKeyArray = typing.Any
   KeyArray = typing.Any
+  threefry_2x32_key = _deprecated_threefry2x32_key
+  rbg_key = _deprecated_rbg_key
+  unsafe_rbg_key = _deprecated_unsafe_rbg_key
 else:
   from jax._src.deprecations import deprecation_getattr as _deprecation_getattr
   __getattr__ = _deprecation_getattr(__name__, _deprecations)

tests/random_test.py

@@ -522,18 +522,21 @@ def test_default_prng_selection(self, make_key, name, impl):
 
   @skipIf(not config.jax_enable_custom_prng, 'relies on typed key upgrade flag')
   def test_explicit_threefry2x32_key(self):
-    self.check_key_has_impl(random.threefry2x32_key(42),
-                            prng_internal.threefry_prng_impl)
+    with self.assertWarnsRegex(DeprecationWarning, "jax.random.threefry2x32_key"):
+      self.check_key_has_impl(random.threefry2x32_key(42),
+                              prng_internal.threefry_prng_impl)
 
   @skipIf(not config.jax_enable_custom_prng, 'relies on typed key upgrade flag')
   def test_explicit_rbg_key(self):
-    self.check_key_has_impl(random.rbg_key(42),
-                            prng_internal.rbg_prng_impl)
+    with self.assertWarnsRegex(DeprecationWarning, "jax.random.rbg_key"):
+      self.check_key_has_impl(random.rbg_key(42),
+                              prng_internal.rbg_prng_impl)
 
   @skipIf(not config.jax_enable_custom_prng, 'relies on typed key upgrade flag')
   def test_explicit_unsafe_rbg_key(self):
-    self.check_key_has_impl(random.unsafe_rbg_key(42),
-                            prng_internal.unsafe_rbg_prng_impl)
+    with self.assertWarnsRegex(DeprecationWarning, "jax.random.unsafe_rbg_key"):
+      self.check_key_has_impl(random.unsafe_rbg_key(42),
+                              prng_internal.unsafe_rbg_prng_impl)
 
   @parameterized.parameters([{'make_key': ctor, 'name': name, 'impl': impl}
                              for ctor in KEY_CTORS
@@ -579,7 +582,7 @@ def test_legacy_prng_key_flag(self):
 
 class ThreefryPrngTest(jtu.JaxTestCase):
   @parameterized.parameters([{'make_key': ctor} for ctor in [
-      random.threefry2x32_key,
+      jax_random.threefry2x32_key,
       partial(random.PRNGKey, impl='threefry2x32'),
       partial(random.key, impl='threefry2x32')]])
   def test_seed_no_implicit_transfers(self, make_key):
@@ -640,7 +643,7 @@ def _CheckChiSquared(self, samples, pmf):
             f'{expected_freq}\n{actual_freq}')
 
   def make_key(self, seed):
-    return random.threefry2x32_key(seed)
+    return random.PRNGKey(seed, impl='threefry2x32')
 
   @jtu.sample_product(
     num=(None, 6, (6,), (2, 3), (2, 3, 4)),
@@ -2296,7 +2299,7 @@ def test_grad_of_prng_key(self):
 @jtu.with_config(jax_default_prng_impl='rbg')
 class LaxRandomWithRBGPRNGTest(LaxRandomTest):
   def make_key(self, seed):
-    return random.rbg_key(seed)
+    return random.PRNGKey(seed, impl='rbg')
 
   def test_split_shape(self):
     key = self.make_key(73)
@@ -2372,7 +2375,7 @@ def test_randint_out_of_range(self):
 @jtu.with_config(jax_default_prng_impl='unsafe_rbg')
 class LaxRandomWithUnsafeRBGPRNGTest(LaxRandomWithRBGPRNGTest):
   def make_key(self, seed):
-    return random.unsafe_rbg_key(seed)
+    return random.PRNGKey(seed, impl="unsafe_rbg")
 
 
 def _sampler_unimplemented_with_custom_prng(*args, **kwargs):