def remainder(x1, x2): x1, x2 = _promote_args("remainder", x1, x2) zero = _constant_like(x1, 0) trunc_mod = lax.rem(x1, x2) trunc_mod_not_zero = lax.ne(trunc_mod, zero) do_plus = lax.bitwise_and( lax.ne(lax.lt(trunc_mod, zero), lax.lt(x2, zero)), trunc_mod_not_zero) return lax.select(do_plus, lax.add(trunc_mod, x2), trunc_mod)
def isfinite(x): _check_arraylike("isfinite", x) dtype = dtypes.dtype(x) if dtypes.issubdtype(dtype, np.floating): return lax.is_finite(x) elif dtypes.issubdtype(dtype, np.complexfloating): return lax.bitwise_and(lax.is_finite(real(x)), lax.is_finite(imag(x))) else: return lax.full_like(x, True, dtype=np.bool_)
def threefry_random_bits(key: jnp.ndarray, bit_width, shape): """Sample uniform random bits of given width and shape using PRNG key.""" if not _is_threefry_prng_key(key): raise TypeError("_random_bits got invalid prng key.") if bit_width not in (8, 16, 32, 64): raise TypeError("requires 8-, 16-, 32- or 64-bit field width.") shape = core.as_named_shape(shape) for name, size in shape.named_items: real_size = lax.psum(1, name) if real_size != size: raise ValueError( f"The shape of axis {name} was specified as {size}, " f"but it really is {real_size}") axis_index = lax.axis_index(name) key = threefry_fold_in(key, axis_index) size = prod(shape.positional) # Compute ceil(bit_width * size / 32) in a way that is friendly to shape # polymorphism max_count, r = divmod(bit_width * size, 32) if r > 0: max_count += 1 if core.is_constant_dim(max_count): nblocks, rem = divmod(max_count, jnp.iinfo(np.uint32).max) else: nblocks, rem = 0, max_count if not nblocks: bits = threefry_2x32(key, lax.iota(np.uint32, rem)) else: keys = threefry_split(key, nblocks + 1) subkeys, last_key = keys[:-1], keys[-1] blocks = vmap(threefry_2x32, in_axes=(0, None))(subkeys, lax.iota(np.uint32, jnp.iinfo(np.uint32).max)) last = threefry_2x32(last_key, lax.iota(np.uint32, rem)) bits = lax.concatenate([blocks.ravel(), last], 0) dtype = UINT_DTYPES[bit_width] if bit_width == 64: bits = [lax.convert_element_type(x, dtype) for x in jnp.split(bits, 2)] bits = lax.shift_left(bits[0], dtype(32)) | bits[1] elif bit_width in [8, 16]: # this is essentially bits.view(dtype)[:size] bits = lax.bitwise_and( np.uint32(np.iinfo(dtype).max), lax.shift_right_logical( lax.broadcast(bits, (1, )), lax.mul( np.uint32(bit_width), lax.broadcasted_iota(np.uint32, (32 // bit_width, 1), 0)))) bits = lax.reshape(bits, (np.uint32(max_count * 32 // bit_width), ), (1, 0)) bits = lax.convert_element_type(bits, dtype)[:size] return lax.reshape(bits, shape)
def _float_divmod(x1, x2): # see float_divmod in floatobject.c of CPython mod = lax.rem(x1, x2) div = lax.div(lax.sub(x1, mod), x2) ind = lax.bitwise_and(mod != 0, lax.sign(x2) != lax.sign(mod)) mod = lax.select(ind, mod + x2, mod) div = lax.select(ind, div - _constant_like(div, 1), div) return lax.round(div), mod
def _power(x1, x2): x1, x2 = _promote_args("power", x1, x2) dtype = dtypes.dtype(x1) if not dtypes.issubdtype(dtype, np.integer): return lax.pow(x1, x2) # Integer power => use binary exponentiation. # TODO(phawkins): add integer pow support to XLA. bits = 6 # Anything more would overflow for any x1 > 1 zero = _constant_like(x2, 0) one = _constant_like(x2, 1) # Initialize acc carefully such that pow(0, x2) is zero for x2 != 0 acc = _where(lax.bitwise_and(lax.eq(x1, zero), lax.ne(x2, zero)), zero, one) for _ in range(bits): acc = _where(lax.bitwise_and(x2, one), lax.mul(acc, x1), acc) x1 = lax.mul(x1, x1) x2 = lax.shift_right_logical(x2, one) return acc
def cond_fun(state): arr, num, i, _ = state return lax.bitwise_and(lax.lt(i, num), lax.lt(i, arr.shape[0]))