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# Copyright (c) 2024 Graphcore Ltd. All rights reserved.
import ml_dtypes
import numpy as np
import pytest
from gfloat import FloatClass, decode_float
from gfloat.formats import *
def _isnegzero(x: float) -> bool:
return (x == 0) and (np.signbit(x) == 1)
def test_spot_check_ocp_e5m2() -> None:
fi = format_info_ocp_e5m2
dec = lambda code: decode_float(fi, code).fval
fclass = lambda code: decode_float(fi, code).fclass
assert dec(0x01) == 2.0**-16
assert dec(0x40) == 2.0
assert _isnegzero(dec(0x80))
assert dec(0x7B) == 57344.0
assert dec(0x7C) == np.inf
assert np.floor(np.log2(dec(0x7B))) == fi.emax
assert dec(0xFC) == -np.inf
assert np.isnan(dec(0x7F))
assert fclass(0x80) == FloatClass.ZERO
assert fclass(0x00) == FloatClass.ZERO
def test_spot_check_ocp_e4m3() -> None:
fi = format_info_ocp_e4m3
dec = lambda code: decode_float(fi, code).fval
assert dec(0x40) == 2.0
assert dec(0x01) == 2.0**-9
assert _isnegzero(dec(0x80))
assert np.isnan(dec(0x7F))
assert dec(0x7E) == 448.0
assert np.floor(np.log2(dec(0x7E))) == fi.emax
def test_spot_check_p3109_p3() -> None:
fi = format_info_p3109(3)
dec = lambda code: decode_float(fi, code).fval
assert dec(0x01) == 2.0**-17
assert dec(0x40) == 1.0
assert np.isnan(dec(0x80))
assert dec(0xFF) == -np.inf
assert np.floor(np.log2(dec(0x7E))) == fi.emax
def test_spot_check_p3109_p1() -> None:
fi = format_info_p3109(1)
dec = lambda code: decode_float(fi, code).fval
assert dec(0x01) == 2.0**-62
assert dec(0x40) == 2.0
assert np.isnan(dec(0x80))
assert dec(0xFF) == -np.inf
assert np.floor(np.log2(dec(0x7E))) == fi.emax
def test_spot_check_binary16() -> None:
fi = format_info_binary16
dec = lambda code: decode_float(fi, code).fval
assert dec(0x3C00) == 1.0
assert dec(0x3C01) == 1.0 + 2**-10
assert dec(0x4000) == 2.0
assert dec(0x0001) == 2**-24
assert dec(0x7BFF) == 65504.0
assert np.isinf(dec(0x7C00))
assert np.isnan(dec(0x7C01))
assert np.isnan(dec(0x7FFF))
def test_spot_check_bfloat16() -> None:
fi = format_info_bfloat16
dec = lambda code: decode_float(fi, code).fval
assert dec(0x3F80) == 1
assert dec(0x4000) == 2
assert dec(0x0001) == 2**-133
assert dec(0x4780) == 65536.0
assert np.isinf(dec(0x7F80))
assert np.isnan(dec(0x7F81))
assert np.isnan(dec(0x7FFF))
def test_spot_check_ocp_e2m3() -> None:
# Test against Table 4 in "OCP Microscaling Formats (MX) v1.0 Spec"
fi = format_info_ocp_e2m3
dec = lambda code: decode_float(fi, code).fval
assert fi.max == 7.5
assert fi.smallest_subnormal == 0.125
assert fi.smallest_normal == 1.0
assert not fi.has_infs
assert fi.num_nans == 0
assert fi.has_nz
assert dec(0b000000) == 0
assert dec(0b011111) == 7.5
assert _isnegzero(dec(0b100000))
def test_spot_check_ocp_e3m2() -> None:
# Test against Table 4 in "OCP Microscaling Formats (MX) v1.0 Spec"
fi = format_info_ocp_e3m2
dec = lambda code: decode_float(fi, code).fval
assert fi.max == 28.0
assert fi.smallest_subnormal == 0.0625
assert fi.smallest_normal == 0.25
assert not fi.has_infs
assert fi.num_nans == 0
assert fi.has_nz
assert dec(0b000000) == 0
assert dec(0b011111) == 28.0
assert _isnegzero(dec(0b100000))
def test_spot_check_ocp_e2m1() -> None:
# Test against Table 5 in "OCP Microscaling Formats (MX) v1.0 Spec"
fi = format_info_ocp_e2m1
dec = lambda code: decode_float(fi, code).fval
assert fi.max == 6.0
assert fi.smallest_subnormal == 0.5
assert fi.smallest_normal == 1.0
assert not fi.has_infs
assert fi.num_nans == 0
assert fi.has_nz
assert dec(0b0000) == 0
assert dec(0b0001) == 0.5
assert dec(0b0010) == 1.0
assert dec(0b0011) == 1.5
assert dec(0b0100) == 2.0
assert dec(0b0101) == 3.0
assert dec(0b0110) == 4.0
assert dec(0b0111) == 6.0
assert _isnegzero(dec(0b1000))
def test_spot_check_ocp_e8m0() -> None:
# Test against Table 7 in "OCP Microscaling Formats (MX) v1.0 Spec"
fi = format_info_ocp_e8m0
dec = lambda code: decode_float(fi, code).fval
fclass = lambda code: decode_float(fi, code).fclass
assert fi.expBias == 127
assert fi.max == 2.0**127
assert fi.smallest == 2.0**-127
assert not fi.has_infs
assert fi.num_nans == 1
assert dec(0x00) == 2.0**-127
assert dec(0x01) == 2.0**-126
assert dec(0x7F) == 1.0
assert np.isnan(dec(0xFF))
assert fclass(0x80) == FloatClass.NORMAL
assert fclass(0x00) == FloatClass.NORMAL
def test_spot_check_ocp_int8() -> None:
# Test against Table TODO in "OCP Microscaling Formats (MX) v1.0 Spec"
fi = format_info_ocp_int8
dec = lambda code: decode_float(fi, code).fval
assert fi.max == 1.0 + 63.0 / 64
assert fi.smallest == 2.0**-6
assert not fi.has_infs
assert fi.num_nans == 0
assert dec(0x00) == 0.0
assert dec(0x01) == fi.smallest
assert dec(0x7F) == fi.max
assert dec(0x80) == -2.0
assert dec(0x80) == fi.min
assert dec(0xFF) == -fi.smallest
@pytest.mark.parametrize("fi", p3109_formats)
def test_specials(fi: FormatInfo) -> None:
assert fi.code_of_nan == 0x80
assert fi.code_of_zero == 0x00
assert fi.code_of_posinf == 0x7F
assert fi.code_of_neginf == 0xFF
@pytest.mark.parametrize("fi", all_formats)
def test_specials_decode(fi: FormatInfo) -> None:
dec = lambda v: decode_float(fi, v).fval
if fi.has_zero:
assert dec(fi.code_of_zero) == 0
if fi.num_nans > 0:
assert np.isnan(dec(fi.code_of_nan))
if fi.has_infs:
assert dec(fi.code_of_posinf) == np.inf
assert dec(fi.code_of_neginf) == -np.inf
assert dec(fi.code_of_max) == fi.max
assert dec(fi.code_of_min) == fi.min
if fi.has_zero:
assert dec(1) == fi.smallest
else:
assert dec(0) == fi.smallest
@pytest.mark.parametrize(
"fmt,npfmt,int_dtype",
[
(format_info_binary16, np.float16, np.uint16),
(format_info_bfloat16, ml_dtypes.bfloat16, np.uint16),
(format_info_ocp_e4m3, ml_dtypes.float8_e4m3fn, np.uint8),
],
)
def test_consistent_decodes_all_values(
fmt: FormatInfo, npfmt: np.dtype, int_dtype: np.dtype
) -> None:
npivals = np.arange(
np.iinfo(int_dtype).min, int(np.iinfo(int_dtype).max) + 1, dtype=int_dtype
)
npfvals = npivals.view(dtype=npfmt)
for i, npfval in zip(npivals, npfvals):
val = decode_float(fmt, int(i))
np.testing.assert_equal(val.fval, npfval)
@pytest.mark.parametrize("v", [-1, 0x10000])
def test_except(v: int) -> None:
with pytest.raises(ValueError):
decode_float(format_info_binary16, v)
@pytest.mark.parametrize("fi", [fi for fi in all_formats if fi.bits <= 8])
def test_dense(fi: FormatInfo) -> None:
fvs = [decode_float(fi, i) for i in range(0, 2**fi.bits)]
vals = np.array([fv.fval for fv in fvs])
assert np.min(vals[np.isfinite(vals)]) == fi.min
assert np.max(vals[np.isfinite(vals)]) == fi.max
assert np.min(vals[np.isfinite(vals) & (vals > 0)]) == fi.smallest
if fi.has_subnormals:
vals_subnormal = np.array(
[fv.fval for fv in fvs if fv.fclass == FloatClass.SUBNORMAL and fv.fval > 0]
)
if len(vals_subnormal):
# In some formats, zero is the only "subnormal"
assert np.min(vals_subnormal) == fi.smallest_subnormal
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