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tinygrad/tinygrad/dtype.py
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chenyuandGitHub 0ce0f51010 generic double cast folding (#11481)
b.cast(a).cast(b) -> b if a preserves all values in b
2025-08-02 19:26:37 -04:00

316 lines
15 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, prod
from enum import Enum, auto
ConstType = float|int|bool
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(Enum): GLOBAL = auto(); LOCAL = auto(); REG = auto() # noqa: E702
@dataclass(frozen=True, eq=False)
class DType(metaclass=DTypeMetaClass):
priority: int # this determines when things get upcasted
itemsize: int
name: str
fmt: FmtStr|None
count: int
_scalar: DType|None
@staticmethod
def new(priority:int, itemsize:int, name:str, fmt:FmtStr|None): return DType(priority, itemsize, name, fmt, 1, None)
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.scalar().name]}"+(f".vec({self.count})" if self.count > 1 else "")
def __lt__(self, o:DType): return (self.priority, self.itemsize, self.name, self.fmt, self.count) < (o.priority, o.itemsize, o.name, o.fmt, o.count)
@property
def base(self): return self
@property
def vcount(self): return self.count
@functools.cache # pylint: disable=method-cache-max-size-none
def vec(self, sz:int) -> DType:
assert self.count == 1, f"can't vectorize {self} with size {sz}"
if sz == 1 or self == dtypes.void: return self # void doesn't vectorize, and sz=1 is scalar
return DType(self.priority, self.itemsize*sz, f"{INVERSE_DTYPES_DICT[self.name]}{sz}", None, sz, self)
def ptr(self, size=-1, addrspace=AddrSpace.GLOBAL) -> PtrDType:
return PtrDType(self.priority, self.itemsize, self.name, self.fmt, self.count, None, self, addrspace, 1, size)
def scalar(self) -> DType: return self._scalar if self._scalar is not None else self
def nbytes(self): raise RuntimeError("only ptr types have nbytes")
@property
def min(self): return dtypes.min(self)
@property
def max(self): return dtypes.max(self)
@dataclass(frozen=True, eq=False)
class PtrDType(DType):
_base: DType
addrspace: AddrSpace
v: int
size: int = -1 # -1 is unlimited size
@property
def base(self): return self._base
@functools.cache # pylint: disable=method-cache-max-size-none
def vec(self, sz:int) -> DType:
assert self.v == 1, f"can't vectorize ptr {self} with size {sz}"
if sz == 1: return self # sz=1 is a scalar
if isinstance(self, ImageDType):
return ImageDType(self.priority, self.itemsize, self.name, self.fmt, self.count, self, self._base, self.addrspace, sz, self.size, self.shape)
return type(self)(self.priority, self.itemsize, self.name, self.fmt, self.count, self, self._base, self.addrspace, sz, self.size)
def ptr(self, size=-1, addrspace=AddrSpace.GLOBAL): raise RuntimeError("can't make a pointer from a pointer")
def nbytes(self) -> int:
if self.size == -1: return 0 # TODO: this should be an exception
return self.size*self.itemsize
@property
def vcount(self): return self.v
def __repr__(self):
return f"{self.base.__repr__()}.ptr({self.size}{', '+str(self.addrspace) if self.addrspace != AddrSpace.GLOBAL else ''})" + \
(f'.vec({self.v})' if self.v != 1 else '')
@dataclass(frozen=True, eq=False)
class ImageDType(PtrDType):
shape: tuple[int, ...] = () # shape of the Image
def ptr(self, size=-1, addrspace=AddrSpace.GLOBAL) -> PtrDType:
assert addrspace == AddrSpace.GLOBAL, "images can't be local"
return self
def __repr__(self): return f"dtypes.{self.name}({self.shape})" + (f'.vec({self.v})' if self.v != 1 else '')
class dtypes:
@staticmethod
@functools.cache
def is_float(x: DType) -> bool: return x.scalar() in dtypes.floats or isinstance(x, ImageDType)
@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.scalar() in dtypes.ints
@staticmethod
@functools.cache
def is_unsigned(x: DType) -> bool: return x.scalar() in dtypes.uints
@staticmethod
def is_bool(x: DType) -> bool: return x.scalar() == dtypes.bool
@staticmethod
def from_py(x) -> DType:
if x.__class__ is float: return dtypes.default_float
if x.__class__ is int: return dtypes.default_int
if x.__class__ is bool: return dtypes.bool
# put this in the last is faster because there are more items than lists/tuples to check
if x.__class__ is list or x.__class__ is 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 as_const(val: tuple[ConstType, ...]|ConstType, dtype:DType):
if isinstance(val, tuple):
assert len(val) == dtype.count, f"mismatch {val} {dtype}"
return tuple(dtypes.as_const(x, dtype) for x in val)
# TODO: should truncate here
return int(val) if dtypes.is_int(dtype) else float(val) if dtypes.is_float(dtype) else bool(val)
@staticmethod
@functools.cache
def min(dtype:DType):
if dtypes.is_int(dtype): return 0 if dtypes.is_unsigned(dtype) else -2**(dtype.itemsize*8-1)
return -float("inf") if dtypes.is_float(dtype) else False
@staticmethod
@functools.cache
def max(dtype:DType):
if dtypes.is_int(dtype): return 2**(dtype.itemsize*8)-1+dtypes.min(dtype)
return float("inf") if dtypes.is_float(dtype) else True
@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.fp8e5m2: (5, 2), dtypes.fp8e4m3: (4, 3)}[dtype]
@staticmethod
def fields() -> dict[str, DType]: return DTYPES_DICT
void: Final[DType] = DType.new(-1, 0, "void", None)
bool: Final[DType] = DType.new(0, 1, "bool", '?')
int8: Final[DType] = DType.new(1, 1, "signed char", 'b')
uint8: Final[DType] = DType.new(2, 1, "unsigned char", 'B')
int16: Final[DType] = DType.new(3, 2, "short", 'h')
uint16: Final[DType] = DType.new(4, 2, "unsigned short", 'H')
int32: Final[DType] = DType.new(5, 4, "int", 'i')
uint32: Final[DType] = DType.new(6, 4, "unsigned int", 'I')
int64: Final[DType] = DType.new(7, 8, "long", 'q')
uint64: Final[DType] = DType.new(8, 8, "unsigned long", 'Q')
fp8e4m3: Final[DType] = DType.new(9, 1, "float8_e4m3", None)
fp8e5m2: Final[DType] = DType.new(10, 1, "float8_e5m2", None)
float16: Final[DType] = DType.new(11, 2, "half", 'e')
# bfloat16 has higher priority than float16, so least_upper_dtype(dtypes.int64, dtypes.uint64) = dtypes.float16
bfloat16: Final[DType] = DType.new(12, 2, "__bf16", None)
float32: Final[DType] = DType.new(13, 4, "float", 'f')
float64: Final[DType] = DType.new(14, 8, "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
# NOTE: these are image dtypes
@staticmethod
def imageh(shp): return ImageDType(100, 2, "imageh", 'e', 1, None, dtypes.float32, AddrSpace.GLOBAL, 1, prod(shp), shp)
@staticmethod
def imagef(shp): return ImageDType(100, 4, "imagef", 'f', 1, None, dtypes.float32, AddrSpace.GLOBAL, 1, prod(shp), shp)
default_float: ClassVar[DType] = float32
default_int: ClassVar[DType] = int32
fp8s = (fp8e4m3, fp8e5m2)
floats = fp8s + (float16, bfloat16, float32, float64)
uints = (uint8, uint16, uint32, uint64)
sints = (int8, int16, int32, int64)
ints = uints + sints
all = floats + ints + (bool,)
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())
# https://jax.readthedocs.io/en/latest/jep/9407-type-promotion.html
# we don't support weak type and complex type
promo_lattice = { dtypes.bool: [dtypes.int8, dtypes.uint8], dtypes.int8: [dtypes.int16], dtypes.int16: [dtypes.int32], dtypes.int32: [dtypes.int64],
dtypes.int64: [dtypes.float16, dtypes.bfloat16], dtypes.uint8: [dtypes.int16, dtypes.uint16], dtypes.uint16: [dtypes.int32, dtypes.uint32],
dtypes.uint32: [dtypes.int64, dtypes.uint64], dtypes.uint64: [dtypes.float16, dtypes.bfloat16],
dtypes.fp8e5m2: [dtypes.float16, dtypes.bfloat16], dtypes.fp8e4m3: [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])) if not (images:=[d for d in ds if isinstance(d, ImageDType)]) else images[0]
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"))}
INVERSE_DTYPES_DICT = {**{v.name:k for k,v in DTYPES_DICT.items()}, "void": "void"}
@functools.cache
def can_safe_cast(dt0:DType, dt1:DType) -> bool:
# return if dt1 preserves value of dt0
# https://numpy.org/doc/stable/reference/generated/numpy.can_cast.html
if dt0 == dt1 or dt0 == dtypes.bool: return True
match dt1:
case dtypes.double: return dt0 in (dtypes.float, dtypes.half, dtypes.bfloat16)
case dtypes.float: return dt0 in (dtypes.half, dtypes.bfloat16)
case dtypes.uint64: return dt0 in (dtypes.uint32, dtypes.uint16, dtypes.uint8)
case dtypes.uint32: return dt0 in (dtypes.uint16, 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 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 truncate_fp16(x):
try: return struct.unpack("@e", struct.pack("@e", float(x)))[0]
except OverflowError: return math.copysign(math.inf, x)
def truncate_bf16(x):
max_bf16 = struct.unpack('f', struct.pack('I', 0x7f7f0000))[0]
if abs(x) > max_bf16: return math.copysign(math.inf, x)
f32_int = struct.unpack('I', struct.pack('f', x))[0]
bf = struct.unpack('f', struct.pack('I', f32_int & 0xFFFF0000))[0]
return bf
# fp8-float conversions based on https://gitlab.com/nvidia/headers/cuda-individual/cudart/-/blob/main/cuda_fp8.hpp
def float_to_fp8(x: float, dtype: DType) -> int:
assert dtype in dtypes.fp8s, "Only for fp8s"
config = {
dtypes.fp8e4m3: {"EXP_BIAS": 7, "SIGNIFICAND_BITS": 4, "MANTISSA_MASK": 0x7, "MINDENORM_O2": 0x3F50000000000000,
"OVERFLOW_THRESHOLD": 0x407D000000000000, "MAXNORM": 0x7E, "MINNORM": 0x3F90000000000000, "INF_VALUE": 0x7F},
dtypes.fp8e5m2: {"EXP_BIAS": 15, "SIGNIFICAND_BITS": 3, "MANTISSA_MASK": 0x3, "MINDENORM_O2": 0x3EE0000000000000,
"OVERFLOW_THRESHOLD": 0x40EE000000000000 - 1, "MAXNORM": 0x7B, "MINNORM": 0x3F10000000000000, "INF_VALUE": 0x7E}
}[dtype]
xbits, = struct.unpack('Q', struct.pack('d', x))
FP8_DP_HALF_ULP = 1 << (53 - config["SIGNIFICAND_BITS"] - 1)
sign = ((xbits >> 63) & 1) << 7
exp = (((xbits >> 52) & 0x7FF) - 1023 + config["EXP_BIAS"])
mantissa = (xbits >> (53 - config["SIGNIFICAND_BITS"])) & config["MANTISSA_MASK"]
absx = xbits & 0x7FFFFFFFFFFFFFFF
if absx <= config["MINDENORM_O2"]: res = 0
elif absx > 0x7FF0000000000000: res = 0x7F if dtype == dtypes.fp8e4m3 else 0x7E | mantissa
elif absx > config["OVERFLOW_THRESHOLD"]: res = config["MAXNORM"]
elif absx >= config["MINNORM"]:
res = ((exp << (config["SIGNIFICAND_BITS"] - 1)) | mantissa)
round_bits = xbits & ((FP8_DP_HALF_ULP << 1) - 1)
if (round_bits > FP8_DP_HALF_ULP) or (round_bits == FP8_DP_HALF_ULP and (mantissa & 1)): res = res + 1
else:
shift = 1 - exp
mantissa |= 1 << (config["SIGNIFICAND_BITS"] - 1)
res = (mantissa >> shift)
round_bits = (xbits | (1 << (53 - 1))) & ((FP8_DP_HALF_ULP << (shift + 1)) - 1)
if (round_bits > (FP8_DP_HALF_ULP << shift)) or (round_bits == (FP8_DP_HALF_ULP << shift) and (res & 1)):
res = res + 1
res |= sign
return int(res)
def fp8_to_float(x: int, dtype: DType) -> float:
assert dtype in dtypes.fp8s, "Only for fp8s"
ur = x << 8
if dtype == dtypes.fp8e5m2 and (ur & 0x7FFF) > 0x7C00: ur = 0x7FFF
elif dtype == dtypes.fp8e4m3:
sign = ur & 0x8000
exponent = ((ur & 0x7800) >> 1) + 0x2000
mantissa = (ur & 0x0700) >> 1
absx = x & 0x7F
if absx == 0x7F: ur = 0x7FFF
elif exponent == 0x2000:
if mantissa != 0:
mantissa <<= 1
while (mantissa & 0x0400) == 0:
mantissa <<= 1
exponent -= 0x0400
mantissa &= 0x03FF
else:
exponent = 0
ur = (sign | exponent) | mantissa
else:
ur = (sign | exponent) | mantissa
half_bytes = struct.pack('<H', ur)
float32_val = struct.unpack('e', half_bytes)[0]
return float(float32_val)
truncate: dict[DType, Callable] = {dtypes.bool: bool,
dtypes.float16: truncate_fp16, dtypes.bfloat16: truncate_bf16,
**{fp8: (lambda x, dtype=fp8: fp8_to_float(float_to_fp8(x, dtype), dtype)) for fp8 in dtypes.fp8s},
dtypes.float32: lambda x: ctypes.c_float(x).value, dtypes.float64: lambda x: ctypes.c_double(x).value,
dtypes.uint8: lambda x: ctypes.c_uint8(x).value, dtypes.uint16: lambda x: ctypes.c_uint16(x).value,
dtypes.uint32: lambda x: ctypes.c_uint32(x).value, dtypes.uint64: lambda x: ctypes.c_uint64(x).value,
dtypes.int8: lambda x: ctypes.c_int8(x).value, dtypes.int16: lambda x: ctypes.c_int16(x).value, dtypes.int32: lambda x: ctypes.c_int32(x).value,
dtypes.int64: lambda x: ctypes.c_int64(x).value}
# numpy and torch dtype interop
def _to_np_dtype(dtype:DType) -> type|None:
import numpy as np
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.fields()[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
# 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.all if (v:=_to_torch_dtype(k)) is not None}[torchdtype]