def _normalize_float(x):
info = dtypes.finfo(dtypes.dtype(x))
int_type = _INT_DTYPES[info.bits]
cond = lax.abs(x) < info.tiny
x1 = _where(cond, x * _lax_const(x, 1 << info.nmant), x)
x2 = _where(cond, int_type(-info.nmant), int_type(0))
return lax.bitcast_convert_type(x1, int_type), x2
def _normalize_float(x): info = dtypes.finfo(dtypes.dtype(x)) cond = lax.abs(x) < info.tiny x1 = _where(cond, x * _lax_const(x, 1 << info.nmant), x) x2 = _where(cond, lax.full_like(x, -info.nmant, dtype=np.int32), lax.full_like(x, 0, dtype=np.int32)) int_type = _INT_DTYPES[info.bits] return lax.bitcast_convert_type(x1, int_type), x2
def testNumpyAndXLAAgreeOnFloatEndianness(self, dtype):
if not FLAGS.jax_enable_x64 and onp.issubdtype(dtype, onp.float64):
raise SkipTest("can't test float64 agreement")
bits_dtype = onp.uint32 if onp.finfo(dtype).bits == 32 else onp.uint64
numpy_bits = onp.array(1., dtype).view(bits_dtype)
xla_bits = api.jit(lambda: lax.bitcast_convert_type(
onp.array(1., dtype), bits_dtype))()
self.assertEqual(numpy_bits, xla_bits)
def testBitcastElementType(
self,
shape,
from_dtype,
to_dtype,
bdims,
):
rng = jtu.rand_default(self.rng())
op = lambda x: lax.bitcast_convert_type(x, to_dtype)
self._CheckBatching(op, 10, bdims, (shape, ), (from_dtype, ), rng)
def ldexp(x1, x2):
_check_arraylike("ldexp", x1, x2)
x1_dtype = dtypes.dtype(x1)
x2_dtype = dtypes.dtype(x2)
if (dtypes.issubdtype(x1_dtype, np.complexfloating)
or dtypes.issubdtype(x2_dtype, np.inexact)):
raise ValueError(
f"ldexp not supported for input types {(x1_dtype, x2_dtype)}")
x1, x2 = _promote_shapes("ldexp", x1, x2)
dtype = dtypes.canonicalize_dtype(dtypes._to_inexact_dtype(x1_dtype))
info = dtypes.finfo(dtype)
int_type = _INT_DTYPES[info.bits]
x1 = lax.convert_element_type(x1, dtype)
x2 = lax.convert_element_type(x2, int_type)
mask = (1 << info.nexp) - 1
bias = ((1 << info.nexp) - 1) >> 1
x, e = _normalize_float(x1)
x2 += e + ((x >> info.nmant) & mask) - bias
# find underflow/overflow before denormalization
underflow_cond = x2 < -(bias + info.nmant)
overflow_cond = x2 > bias
m = lax.full_like(x, 1, dtype=dtype)
# denormals
cond = x2 < -bias + 1
x2 = _where(cond, x2 + info.nmant, x2)
m = _where(cond, m / (1 << info.nmant), m)
x2 = lax.convert_element_type(x2, np.int32)
x &= ~(mask << info.nmant)
x |= ((lax.convert_element_type(x2, int_type) + bias) << info.nmant)
x = lax.convert_element_type(m, dtype) * lax.bitcast_convert_type(x, dtype)
# underflow
x = _where(underflow_cond, lax.full_like(x, 0, dtype=dtype), x)
# overflow
x = _where(overflow_cond, lax.sign(x1) * lax.full_like(x, np.inf), x)
# ldexp(x1, x2) = x1 for x1 = inf, -inf, nan, 0
return _where(isinf(x1) | isnan(x1) | (x1 == 0), x1, x)
def frexp(x):
_check_arraylike("frexp", x)
x, = _promote_dtypes_inexact(x)
if dtypes.issubdtype(x.dtype, np.complexfloating):
raise TypeError("frexp does not support complex-valued inputs")
dtype = dtypes.dtype(x)
info = dtypes.finfo(dtype)
mask = (1 << info.nexp) - 1
bias = ((1 << info.nexp) - 1) >> 1
x1, x2 = _normalize_float(x)
x2 += ((x1 >> info.nmant) & mask) - bias + 1
x1 &= ~(mask << info.nmant)
x1 |= (bias - 1) << info.nmant
x1 = lax.bitcast_convert_type(x1, dtype)
cond = isinf(x) | isnan(x) | (x == 0)
x2 = _where(cond, lax_internal._zeros(x2), x2)
return _where(cond, x, x1), lax.convert_element_type(x2, np.int32)
def ldexp(x1, x2):
_check_arraylike("ldexp", x1, x2)
dtype = dtypes.canonicalize_dtype(_result_dtype(np.ldexp, x1, x2))
x1, x2 = _promote_shapes("ldexp", x1, x2)
x1 = lax.convert_element_type(x1, dtype)
info = dtypes.finfo(dtype)
mask = (1 << info.nexp) - 1
bias = ((1 << info.nexp) - 1) >> 1
int_type = _INT_DTYPES[info.bits]
x, e = _normalize_float(x1)
x2 += e + ((x >> info.nmant) & mask) - bias
# find underflow/overflow before denormalization
underflow_cond = x2 < -(bias + info.nmant)
overflow_cond = x2 > bias
m = lax.full_like(x, 1, dtype=dtype)
# denormals
cond = x2 < -bias + 1
x2 = _where(cond, x2 + info.nmant, x2)
m = _where(cond, m / (1 << info.nmant), m)
x2 = lax.convert_element_type(x2, np.int32)
x &= ~(mask << info.nmant)
x |= ((lax.convert_element_type(x2, int_type) + bias) << info.nmant)
x = lax.convert_element_type(m, dtype) * lax.bitcast_convert_type(x, dtype)
# underflow
x = _where(underflow_cond, lax.full_like(x, 0, dtype=dtype), x)
# overflow
x = _where(overflow_cond, lax.sign(x1) * lax.full_like(x, np.inf), x)
# ldexp(x1, x2) = x1 for x1 = inf, -inf, nan, 0
return _where(isinf(x1) | isnan(x1) | (x1 == 0), x1, x)
def signbit(x):
x, = _promote_args("signbit", x)
dtype = dtypes.dtype(x)
if dtypes.issubdtype(dtype, np.integer):
return lax.lt(x, _constant_like(x, 0))
elif dtypes.issubdtype(dtype, np.bool_):
return lax.full_like(x, False, dtype=np.bool_)
elif not dtypes.issubdtype(dtype, np.floating):
raise ValueError("jax.numpy.signbit is not well defined for %s" %
dtype)
# TPU supports BF16 but not S16 types, so as a workaround, convert BF16 to
# F32.
if dtype == dtypes.bfloat16:
dtype = np.float32
x = lax.convert_element_type(x, np.float32)
info = dtypes.finfo(dtype)
if info.bits not in _INT_DTYPES:
raise NotImplementedError(
"jax.numpy.signbit only supports 16, 32, and 64-bit types.")
int_type = _INT_DTYPES[info.bits]
x = lax.bitcast_convert_type(x, int_type)
return lax.convert_element_type(x >> (info.nexp + info.nmant), np.bool_)
def testNumpyAndXLAAgreeOnFloatEndianness(self, dtype):
bits_dtype = np.uint32 if jnp.finfo(dtype).bits == 32 else np.uint64
numpy_bits = np.array(1., dtype).view(bits_dtype)
xla_bits = api.jit(
lambda: lax.bitcast_convert_type(np.array(1., dtype), bits_dtype))()
self.assertEqual(numpy_bits, xla_bits)
def testBitcastElementType(self, shape, from_dtype, to_dtype, bdims,
rng_factory):
rng = rng_factory(self.rng())
op = lambda x: lax.bitcast_convert_type(x, to_dtype)
self._CheckBatching(op, 10, bdims, (shape, ), (from_dtype, ), rng)
