jax.nn.one_hot: deprecate non-integer inputs

jax/_src/deprecations.py

@@ -125,6 +125,7 @@ def warn(deprecation_id: str, message: str, stacklevel: int) -> None:
 # always registered by the time `accelerate` and `is_acelerated` are called.
 register('jax-aval-named-shape')
 register('jax-dlpack-import-legacy')
+register('jax-nn-one-hot-float-input')
 register("jax-numpy-astype-complex-to-real")
 register("jax-numpy-array-none")
 register('jax-numpy-clip-args')

jax/_src/nn/functions.py

@@ -29,6 +29,7 @@
 from jax import lax
 from jax._src import config
 from jax._src import core
+from jax._src import deprecations
 from jax._src import dtypes
 from jax._src import util
 from jax._src.core import AxisName
@@ -645,34 +646,33 @@ def standardize(x: ArrayLike,
 
 # TODO(slebedev): Change the type of `x` to `ArrayLike`.
 @partial(jax.jit, static_argnames=("num_classes", "dtype", "axis"))
-def _one_hot(x: Any, num_classes: int, *,
+def _one_hot(x: Array, num_classes: int, *,
              dtype: Any, axis: int | AxisName) -> Array:
   num_classes = core.concrete_dim_or_error(
       num_classes,
       "The error arose in jax.nn.one_hot argument `num_classes`.")
   dtype = dtypes.canonicalize_dtype(dtype)
-  x_arr = jnp.asarray(x)
   try:
-    output_pos_axis = util.canonicalize_axis(axis, x_arr.ndim + 1)
+    output_pos_axis = util.canonicalize_axis(axis, x.ndim + 1)
   except TypeError:
     axis_size = lax.psum(1, axis)
     if num_classes != axis_size:
       raise ValueError(f"Expected num_classes to match the size of axis {axis}, "
                        f"but {num_classes} != {axis_size}") from None
     axis_idx = lax.axis_index(axis)
-    return jnp.asarray(x_arr == axis_idx, dtype=dtype)
+    return jnp.asarray(_dot_product_attention_xla == axis_idx, dtype=dtype)
   axis = operator.index(axis)  # type: ignore[arg-type]
-  lhs = lax.expand_dims(x_arr, (axis,))
-  rhs_shape = [1] * x_arr.ndim
+  lhs = lax.expand_dims(x, (axis,))
+  rhs_shape = [1] * x.ndim
   rhs_shape.insert(output_pos_axis, num_classes)
   if config.sharding_in_types.value:
     # TODO(yashkatariya): Maybe expose `out_sharding` on `one_hot` too?
-    rhs_sharding = NamedSharding(x_arr.sharding.mesh, P(*[None] * len(rhs_shape)))
+    rhs_sharding = NamedSharding(x.sharding.mesh, P(*[None] * len(rhs_shape)))  # pytype: disable=attribute-error
   else:
     rhs_sharding = None
-  rhs = lax.broadcasted_iota(x_arr.dtype, rhs_shape, output_pos_axis,
+  rhs = lax.broadcasted_iota(x.dtype, rhs_shape, output_pos_axis,
                              _sharding=rhs_sharding)
-  return jnp.asarray(lhs == rhs, dtype=dtype)
+  return (lhs == rhs).astype(dtype)
 
 # TODO(slebedev): Change the type of `x` to `ArrayLike`.
 def one_hot(x: Any, num_classes: int, *,
@@ -703,7 +703,15 @@ def one_hot(x: Any, num_classes: int, *,
   num_classes = core.concrete_dim_or_error(
       num_classes,
       "The error arose in jax.nn.one_hot argument `num_classes`.")
-  return _one_hot(x, num_classes, dtype=dtype, axis=axis)
+  x_arr = jnp.asarray(x)
+  if not jnp.isdtype(x_arr.dtype, "integral"):
+    # Deprecated 2024-12-18
+    deprecations.warn(
+      'jax-nn-one-hot-float-input',
+      f"jax.nn.one_hot input should be integer-typed; got dtype={x_arr.dtype}",
+      stacklevel=1)
+    x_arr = x_arr.astype('int32')
+  return _one_hot(x_arr, num_classes, dtype=dtype, axis=axis)
 
 
 @jax.custom_jvp

tests/nn_test.py

@@ -24,10 +24,11 @@
 
 import scipy.stats
 
+from jax._src import ad_checkpoint
 from jax._src import config
 from jax._src import core
+from jax._src import deprecations
 from jax._src import test_util as jtu
-from jax._src import ad_checkpoint
 from jax._src.interpreters import mlir
 from jax._src.lib import cuda_versions
 from jax.test_util import check_grads
@@ -530,6 +531,15 @@ def testOneHotAxis(self):
     actual = nn.one_hot(jnp.array([1, 2, 0]), 3, axis=-2)
     self.assertAllClose(actual, expected, check_dtypes=False)
 
+  def testOneHotNonInteger(self):
+    def assert_warns_or_errors(msg):
+      if deprecations.is_accelerated("jax-nn-one-hot-float-input"):
+        return self.assertRaisesRegex(ValueError, msg)
+      else:
+        return self.assertWarnsRegex(DeprecationWarning, msg)
+    with assert_warns_or_errors("jax.nn.one_hot input should be integer-typed"):
+      nn.one_hot(jnp.array([1.0]), 3)
+
   def testTanhExists(self):
     nn.tanh  # doesn't crash
 

tests/shape_poly_test.py

@@ -2760,11 +2760,11 @@ def f(x_ref):
                 expect_error=expect_error_associative_scan),
     PolyHarness("one_hot", "poly_num_classes",
                 lambda x, y: jax.nn.one_hot(x, y.shape[0]),
-                arg_descriptors=[np.arange(16, dtype=_f32), RandArg((16,), _f32)],
+                arg_descriptors=[np.arange(16, dtype=_i32), RandArg((16,), _f32)],
                 polymorphic_shapes=[None, "b0, ..."]),
     PolyHarness("one_hot", "all_poly",
                 lambda x, y: jax.nn.one_hot(x, y.shape[0]),
-                arg_descriptors=[np.arange(16, dtype=_f32), RandArg((16,), _f32)],
+                arg_descriptors=[np.arange(16, dtype=_i32), RandArg((16,), _f32)],
                 polymorphic_shapes=["b, ...", "b, ..."]),
     PolyHarness("ones", "",
                 lambda x: jnp.ones(x.shape, dtype=_f32) + x,