Files
tinygrad/tinygrad/dtype.py
T
2026-07-16 16:12:33 -04:00

316 lines
16 KiB
Python

from __future__ import annotations
from typing import Final, ClassVar, Callable, Literal
import math, struct, ctypes, functools
from dataclasses import dataclass, fields
from tinygrad.helpers import getenv
from enum import IntEnum, auto
class ConstFloat(float):
"""Float subclass that distinguishes -0.0 from 0.0 and where nan == nan."""
__slots__ = ('bits',)
bits: int
def __new__(cls, v:float):
obj = super().__new__(cls, v)
obj.bits = struct.unpack('<Q', struct.pack('<d', v))[0]
return obj
def __eq__(self, other):
if self is other: return True
if isinstance(other, float) and math.isnan(self) and math.isnan(other): return True
return float.__eq__(self, other)
def __hash__(self): return hash(self.bits)
def __repr__(self): return f"ConstFloat({float.__repr__(self)})"
def __str__(self): return float.__repr__(self)
class InvalidType:
_instance: ClassVar[InvalidType|None] = None
def __new__(cls):
if cls._instance is None: cls._instance = object.__new__(cls)
return cls._instance
def __eq__(self, other): return self is other
def __hash__(self): return id(self)
def __repr__(self): return "Invalid"
def __reduce__(self): return (InvalidType, ()) # unpickle returns the singleton
def __format__(self, spec): return "Invalid"
Invalid = InvalidType()
PyConst = float|int|bool
ConstType = PyConst|InvalidType
FmtStr = Literal['?', 'b', 'B', 'h', 'H', 'i', 'I', 'q', 'Q', 'e', 'f', 'd']
# all DTypes should only be created once
class DTypeMetaClass(type):
dcache: dict[tuple, DType] = {}
def __call__(cls, *args, **kwargs):
if (ret:=DTypeMetaClass.dcache.get(args, None)) is not None: return ret
DTypeMetaClass.dcache[args] = ret = super().__call__(*args)
return ret
class AddrSpace(IntEnum):
def __str__(self): return repr(self)
def __repr__(self): return f"{self.__class__.__name__}.{self.name}"
GLOBAL = auto(); LOCAL = auto(); REG = auto(); ALU = auto() # noqa: E702
@dataclass(frozen=True, eq=False)
class DType(metaclass=DTypeMetaClass):
priority: int # this determines when things get upcasted
bitsize: int
name: str
fmt: FmtStr|None
@property
def itemsize(self) -> int: return (self.bitsize + 7) // 8
@staticmethod
def new(priority:int, bitsize:int, name:str, fmt:FmtStr|None): return DType(priority, bitsize, name, fmt)
def __reduce__(self): return type(self), tuple(getattr(self, f.name) for f in fields(self))
def __repr__(self): return f"dtypes.{INVERSE_DTYPES_DICT[self.name]}"
def __lt__(self, o:DType): return (self.priority, self.bitsize, self.name, self.fmt) < (o.priority, o.bitsize, o.name, o.fmt)
def scalar(self) -> DType: return self
@functools.cached_property
def min(self):
if dtypes.is_int(self): return 0 if dtypes.is_unsigned(self) else -2**(self.bitsize-1)
return -float("inf") if dtypes.is_float(self) else False
@functools.cached_property
def max(self):
if dtypes.is_int(self): return 2**(self.bitsize)-1+self.min
return float("inf") if dtypes.is_float(self) else True
def const(self, val: tuple[ConstType, ...]|ConstType):
if isinstance(val, tuple): return tuple(map(self.const, val))
if isinstance(val, InvalidType): return val
# NOTE: float('nan') != float('nan'), so we canonicalize here
if isinstance(val, float) and math.isnan(val): val = math.nan
# int is the default. wrap floats in ConstFloat to distinguish -0.0 from 0.0 in cache
return ConstFloat(float(val)) if dtypes.is_float(self) else bool(val) if dtypes.is_bool(self) else int(val)
class dtypes:
@staticmethod
@functools.cache
def is_float(x: DType) -> bool: return x in (dtypes.floats + (dtypes.weakfloat,))
@staticmethod # static methods on top, or bool in the type info will refer to dtypes.bool
@functools.cache
def is_int(x: DType) -> bool: return x in (dtypes.ints + (dtypes.weakint, dtypes.index))
@staticmethod
@functools.cache
def is_unsigned(x: DType) -> bool: return x in dtypes.uints
@staticmethod
def is_bool(x: DType) -> bool: return x == dtypes.bool
@staticmethod
def from_py(x) -> DType:
# NOTE: isinstance(True, int) is True, so bool must be checked before int
if isinstance(x, (bool, InvalidType)): return dtypes.bool
if isinstance(x, float): return dtypes.default_float
if isinstance(x, int): return dtypes.default_int
# put this in the last is faster because there are more items than lists/tuples to check
if isinstance(x, (list, tuple)): return max(dtypes.from_py(xi) for xi in x) if x else dtypes.default_float
raise RuntimeError(f"Could not infer dtype of {x} with type {type(x)}")
@staticmethod
def finfo(dtype:DType) -> tuple[int, int]:
"""(exponent, mantissa)"""
if not dtypes.is_float(dtype): raise ValueError(f"{dtype} is not a floating point type")
return {dtypes.float16: (5, 10), dtypes.bfloat16: (8, 7), dtypes.float32: (8, 23), dtypes.float64: (11, 52),
dtypes.fp8e4m3: (4, 3), dtypes.fp8e5m2: (5, 2), dtypes.fp8e4m3fnuz: (4, 3), dtypes.fp8e5m2fnuz: (5, 2)}[dtype]
void: Final[DType] = DType.new(-1, 0, "void", None)
weakint: Final[DType] = DType.new(0, 800, "weakint", None)
index: Final[DType] = DType.new(0, 800, "index", None) # NOTE: not in the promo lattice: index math never mixes dtypes
bool: Final[DType] = DType.new(0, 1, "bool", '?')
int8: Final[DType] = DType.new(1, 8, "signed char", 'b')
uint8: Final[DType] = DType.new(2, 8, "unsigned char", 'B')
int16: Final[DType] = DType.new(3, 16, "short", 'h')
uint16: Final[DType] = DType.new(4, 16, "unsigned short", 'H')
int32: Final[DType] = DType.new(5, 32, "int", 'i')
uint32: Final[DType] = DType.new(6, 32, "unsigned int", 'I')
int64: Final[DType] = DType.new(7, 64, "long", 'q')
uint64: Final[DType] = DType.new(8, 64, "unsigned long", 'Q')
_uint128: Final[DType] = DType.new(8, 128, "uint128", None)
_uint256: Final[DType] = DType.new(8, 256, "uint256", None)
weakfloat: Final[DType] = DType.new(9, 800, "weakfloat", None)
fp8e4m3: Final[DType] = DType.new(10, 8, "float8_e4m3", None)
fp8e5m2: Final[DType] = DType.new(11, 8, "float8_e5m2", None)
fp8e4m3fnuz: Final[DType] = DType.new(10, 8, "float8_e4m3fnuz", None)
fp8e5m2fnuz: Final[DType] = DType.new(11, 8, "float8_e5m2fnuz", None)
float16: Final[DType] = DType.new(12, 16, "half", 'e')
# bfloat16 has higher priority than float16, so least_upper_dtype(dtypes.int64, dtypes.uint64) = dtypes.float16
bfloat16: Final[DType] = DType.new(13, 16, "__bf16", None)
float32: Final[DType] = DType.new(14, 32, "float", 'f')
float64: Final[DType] = DType.new(15, 64, "double", 'd')
# dtype aliases
half = float16; float = float32; double = float64 # noqa: E702
uchar = uint8; ushort = uint16; uint = uint32; ulong = uint64 # noqa: E702
char = int8; short = int16; int = int32; long = int64 # noqa: E702
default_float: ClassVar[DType] = float32
default_int: ClassVar[DType] = int32
fp8_ocp = (fp8e4m3, fp8e5m2)
fp8_fnuz = (fp8e4m3fnuz, fp8e5m2fnuz)
fp8s = fp8_ocp + fp8_fnuz
floats = fp8s + (float16, bfloat16, float32, float64)
int8s = (uint8, int8)
int16s = (uint16, int16)
int32s = (uint32, int32)
int64s = (uint64, int64)
uints = (uint8, uint16, uint32, uint64)
sints = (int8, int16, int32, int64)
ints = uints + sints
weaks = (weakint, weakfloat)
all = floats + ints + (bool,) # noqa: A003
if (env_default_float := getenv("DEFAULT_FLOAT", "")):
dtypes.default_float = getattr(dtypes, env_default_float.lower())
assert dtypes.is_float(dtypes.default_float), f"{env_default_float} is not a float dtype"
DTypeLike = str|DType
def to_dtype(dtype:DTypeLike) -> DType: return dtype if isinstance(dtype, DType) else getattr(dtypes, dtype.lower())
def strong_dtype(dtype:DType) -> DType:
return dtypes.default_int if dtype == dtypes.weakint else dtypes.default_float if dtype == dtypes.weakfloat else dtype
# https://jax.readthedocs.io/en/latest/jep/9407-type-promotion.html
# we don't support complex type
promo_lattice = { dtypes.bool: [dtypes.weakint], dtypes.weakint: [dtypes.int8, dtypes.uint8],
dtypes.int8: [dtypes.int16], dtypes.int16: [dtypes.int32], dtypes.int32: [dtypes.int64],
dtypes.int64: [dtypes.uint64], dtypes.uint8: [dtypes.int16, dtypes.uint16], dtypes.uint16: [dtypes.int32, dtypes.uint32],
dtypes.uint32: [dtypes.int64, dtypes.uint64], dtypes.uint64: [dtypes.weakfloat],
dtypes.weakfloat: [dtypes.fp8e4m3, dtypes.fp8e5m2, dtypes.fp8e4m3fnuz, dtypes.fp8e5m2fnuz],
dtypes.fp8e4m3: [dtypes.float16, dtypes.bfloat16], dtypes.fp8e5m2: [dtypes.float16, dtypes.bfloat16],
dtypes.fp8e4m3fnuz: [dtypes.float16, dtypes.bfloat16], dtypes.fp8e5m2fnuz: [dtypes.float16, dtypes.bfloat16],
dtypes.float16: [dtypes.float32], dtypes.bfloat16: [dtypes.float32], dtypes.float32: [dtypes.float64], }
@functools.cache
def _get_recursive_parents(dtype:DType) -> set[DType]:
return set.union(*[_get_recursive_parents(d) for d in promo_lattice[dtype]], {dtype}) if dtype != dtypes.float64 else {dtypes.float64}
@functools.cache
def least_upper_dtype(*ds:DType) -> DType:
return min(set.intersection(*[_get_recursive_parents(d) for d in ds]))
def least_upper_float(dt:DType) -> DType: return dt if dtypes.is_float(dt) else least_upper_dtype(dt, dtypes.default_float)
DTYPES_DICT = {k: v for k, v in dtypes.__dict__.items() if isinstance(v, DType) and not k.startswith(("default", "void", "weak", "index", "_"))}
INVERSE_DTYPES_DICT = {**{v.name:k for k,v in DTYPES_DICT.items()}, "void": "void", "weakint":"weakint", "index":"index", "weakfloat":"weakfloat"}
@functools.cache
def can_lossless_cast(dt0:DType, dt1:DType) -> bool:
# return if dt1 preserves value of dt0
# similar to https://numpy.org/doc/stable/reference/generated/numpy.can_cast.html
if dt0 == dt1 or dt0 == dtypes.bool: return True
match dt1:
case dtypes.weakint | dtypes.index: return dt0 in dtypes.ints
case dtypes.double: return dt0 in (dtypes.float, dtypes.half, dtypes.bfloat16, *dtypes.fp8s,
dtypes.uint32, dtypes.uint16, dtypes.uint8, dtypes.int32, dtypes.int16, dtypes.int8)
case dtypes.float: return dt0 in (dtypes.half, dtypes.bfloat16, *dtypes.fp8s, dtypes.uint16, dtypes.uint8, dtypes.int16, dtypes.int8)
case dtypes.half: return dt0 in (*dtypes.fp8s, dtypes.uint8, dtypes.int8)
case dtypes.uint64: return dt0 in (dtypes.uint32, dtypes.uint16, dtypes.uint8)
case dtypes.uint32: return dt0 in (dtypes.uint16, dtypes.uint8)
case dtypes.uint16: return dt0 in (dtypes.uint8,)
case dtypes.int64: return dt0 in (dtypes.uint32, dtypes.uint16, dtypes.uint8, dtypes.int32, dtypes.int16, dtypes.int8)
case dtypes.int32: return dt0 in (dtypes.uint16, dtypes.uint8, dtypes.int16, dtypes.int8)
case dtypes.int16: return dt0 in (dtypes.uint8, dtypes.int8)
case _: return False
def sum_acc_dtype(dt:DType):
# default acc dtype for sum
if dt in dtypes.weaks: return dt
if dtypes.is_unsigned(dt): return least_upper_dtype(dt, dtypes.uint)
if dtypes.is_int(dt) or dt == dtypes.bool: return least_upper_dtype(dt, dtypes.int)
return least_upper_dtype(dt, to_dtype(getenv("SUM_DTYPE", "float32")))
def float_to_fp16(x):
try: return struct.unpack('e', struct.pack('e', float(x)))[0]
except OverflowError: return math.copysign(math.inf, x)
def float_to_bf16(x):
if not math.isfinite(x): return x
u = struct.unpack('I', struct.pack('f', x))[0]
u = (u + 0x7FFF + ((u >> 16) & 1)) & 0xFFFF0000
return struct.unpack('f', struct.pack('I', u))[0]
# fp8-float conversions based on https://gitlab.com/nvidia/headers/cuda-individual/cudart/-/blob/main/cuda_fp8.hpp
# (bias, sig_bits, mant_mask, min_denorm_half, ovf_threshold, max_norm, min_norm)
_fp8_cfg = {
dtypes.fp8e4m3: (7, 4, 0x7, 0x3F50000000000000, 0x407D000000000000, 0x7E, 0x3F90000000000000),
dtypes.fp8e5m2: (15, 3, 0x3, 0x3EE0000000000000, 0x40EE000000000000-1, 0x7B, 0x3F10000000000000),
dtypes.fp8e4m3fnuz: (8, 4, 0x7, 0x3F40000000000000, 0x406F000000000000-1, 0x7F, 0x3F80000000000000),
dtypes.fp8e5m2fnuz: (16, 3, 0x3, 0x3ED0000000000000, 0x40EE000000000000-1, 0x7F, 0x3F00000000000000),
}
def float_to_fp8(x: float, dtype: DType) -> int:
assert dtype in dtypes.fp8s, "Only for fp8s"
if dtype in dtypes.fp8_fnuz and not math.isfinite(x): return 0x80
if dtype in dtypes.fp8_fnuz and x == 0.0: return 0x00
# e4m3 don't support inf, return 0x7f(+NaN) and 0xff(-NaN) to match jax
# NaN is unordered, can't compare with zero, use math.copysign to get sign
if dtype == dtypes.fp8e4m3 and not math.isfinite(x): return 0x7f if math.copysign(1, x) > 0 else 0xff
if dtype == dtypes.fp8e5m2 and not math.isfinite(x): return (0 if math.copysign(1, x) > 0 else 0x80) | (0x7c if math.isinf(x) else 0x7f)
bias, sig_bits, mant_mask, min_denorm_half, ovf_threshold, max_norm, min_norm = _fp8_cfg[dtype]
xbits, = struct.unpack('Q', struct.pack('d', x))
half_ulp = 1 << (52 - sig_bits)
sign, exp, mantissa, absx = ((xbits>>63)&1)<<7, ((xbits>>52)&0x7FF)-1023+bias, (xbits>>(53-sig_bits))&mant_mask, xbits&0x7FFFFFFFFFFFFFFF
if absx <= min_denorm_half: res = 0
elif absx > ovf_threshold: res = max_norm
elif absx >= min_norm:
res, round_bits = (exp << (sig_bits - 1)) | mantissa, xbits & ((half_ulp << 1) - 1)
if round_bits > half_ulp or (round_bits == half_ulp and mantissa & 1): res += 1
else:
shift = 1 - exp
mantissa |= 1 << (sig_bits - 1)
res, half = mantissa >> shift, half_ulp << shift
round_bits = (xbits | (1 << 52)) & ((half << 1) - 1)
if round_bits > half or (round_bits == half and res & 1): res += 1
return 0 if dtype in dtypes.fp8_fnuz and res == 0 else int(res | sign) # fnuz has no negative zero
def fp8_to_float(x: int, dtype: DType) -> float:
assert dtype in dtypes.fp8s, "Only for fp8s"
if dtype in dtypes.fp8_fnuz and x == 0x80: return math.nan
if (x & 0x7F) == 0: return -0.0 if x & 0x80 else 0.0
bias, sig_bits, *_ = _fp8_cfg[dtype]
mant_bits, exp_bits = sig_bits - 1, 8 - sig_bits
exp_max, mant_max = (1 << exp_bits) - 1, (1 << mant_bits) - 1
sign, exp, mantissa = (x >> 7) & 1, (x >> mant_bits) & exp_max, x & mant_max
if dtype not in dtypes.fp8_fnuz and exp == exp_max:
if dtype == dtypes.fp8e5m2: return math.copysign(math.nan if mantissa else math.inf, -1 if sign else 1)
if mantissa == mant_max: return math.nan
val = (mantissa / (mant_max + 1)) * 2 ** (1 - bias) if exp == 0 else (1 + mantissa / (mant_max + 1)) * 2 ** (exp - bias)
return -val if sign else val
def storage_fmt_for_dtype(dtype:DType): return 'H' if dtype == dtypes.bfloat16 else 'B' if dtype in dtypes.fp8s else dtype.fmt
def to_storage_scalar(x, dtype:DType):
if dtype == dtypes.half: return float_to_fp16(x)
if dtype == dtypes.bfloat16: return (struct.unpack('I', struct.pack('f', float_to_bf16(x)))[0] >> 16) & 0xFFFF
if dtype in dtypes.fp8s: return float_to_fp8(float(x), dtype)
return x
def from_storage_scalar(x, dtype:DType):
if dtype == dtypes.bfloat16: return struct.unpack('f', struct.pack('I', (x & 0xFFFF) << 16))[0]
if dtype in dtypes.fp8s: return fp8_to_float(int(x), dtype)
return x
truncate: dict[DType, Callable] = {dtypes.bool: bool,
dtypes.float16: float_to_fp16, dtypes.bfloat16: lambda x: float_to_bf16(float(x)),
**{fp8: (lambda x, dtype=fp8: fp8_to_float(float_to_fp8(x, dtype), dtype)) for fp8 in dtypes.fp8s},
**{getattr(dtypes, n): (lambda x, c=getattr(ctypes, f'c_{n}'): c(x).value)
for n in ('float', 'double', 'int8', 'int16', 'int32', 'int64', 'uint8', 'uint16', 'uint32', 'uint64')}}
# numpy and torch dtype interop
def _to_np_dtype(dtype:DType) -> type|None:
import numpy as np
if dtype in { dtypes.bfloat16, *dtypes.fp8s }: return np.float32
return np.dtype(dtype.fmt).type if dtype.fmt is not None else None
def _from_np_dtype(npdtype:'np.dtype') -> DType: # type: ignore [name-defined] # noqa: F821
import numpy as np
return DTYPES_DICT[np.dtype(npdtype).name]
@functools.cache
def _to_torch_dtype(dtype:DType) -> 'torch.dtype'|None: # type: ignore [name-defined] # noqa: F821
import numpy as np, torch
if dtype == dtypes.uint64: return torch.uint64
if dtype == dtypes.bfloat16: return torch.bfloat16
if dtype in dtypes.fp8s: return torch.uint8
# NOTE: torch doesn't expose this mapping with a stable API
try: return torch.from_numpy(np.array([], dtype=_to_np_dtype(dtype))).dtype
except TypeError: return None
@functools.cache
def _from_torch_dtype(torchdtype:'torch.dtype') -> DType: # type: ignore [name-defined] # noqa: F821
return {v:k for k in DTYPES_DICT.values() if (v:=_to_torch_dtype(k)) is not None}[torchdtype]