en-dtypes 0.0.3

Experimental numpy dtypes

en_dtypes

en_dtypes is a stand-alone implementation of several Experimental NumPy dtype Extensions used in machine learning libraries, including:

• Microscaling (MX)-compliant data formats:
  • float4_e2m1
  • float4_e1m2
  • float6_e2m3
  • float6_e3m2
  • float8_e8m0
• Ascend HiFloat8:
  • hifloat8

See below for specifications of these number formats.

Installation

The en_dtypes package is tested with Python versions 3.7-3.12, and can be installed with the following command:

pip3 install en-dtypes

To build from source, clone the repository and run:

git submodule init
git submodule update
pip3 install .

Example Usage

>>> from en_dtypes import float4_e2m1, hifloat8
>>> import numpy as np
>>> np.zeros(4, dtype=float4_e2m1)
array([0, 0, 0, 0], dtype=float4_e2m1)
>>> np.zeros(4, dtype=hifloat8)
array([0, 0, 0, 0], dtype=hifloat8)

Microscaling (MX)-compliant data formats

float4_e2m1

Exponent: 2, Mantissa: 1, bias: 1.

Extended range: no inf, no NaN.

Microscaling format, 4 bits (encoding: 0bSEEM) using byte storage (higher 4 bits are unused). NaN representation is undefined.

Possible absolute values: [0, 0.5, 1, 1.5, 2, 3, 4, 6]

float4_e1m2

Exponent: 1, Mantissa: 2, bias: 1.

Extended range: no inf, no NaN.

Microscaling format, 4 bits (encoding: 0bSEMM) using byte storage (higher 4 bits are unused). NaN representation is undefined.

Possible absolute values: [0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75]

float6_e2m3

Exponent: 2, Mantissa: 3, bias: 1.

Extended range: no inf, no NaN.

Microscaling format, 6 bits (encoding: 0bSEEMMM) using byte storage (higher 2 bits are unused). NaN representation is undefined.

Possible values range: [-7.5; 7.5]

float6_e3m2

Exponent: 3, Mantissa: 2, bias: 3.

Extended range: no inf, no NaN.

Microscaling format, 4 bits (encoding: 0bSEEEMM) using byte storage (higher 2 bits are unused). NaN representation is undefined.

Possible values range: [-28; 28]

float8_e8m0

scale format E8M0, which has the following properties:

• Unsigned format
• 8 exponent bits
• Exponent range from -127 to 127
• No zero and infinity
• Single NaN value (0xFF).

Ascend data formats

hifloat8

HiFloat8 is a 8-bit floating point format used in Ascend devices. It has the following properties:

• Sign field with 1 bit
• Dot field with 2 to 4 bits
• Exponent field with 0 to 4 bits implicated by dot field
• Mantissa field with 1 to 3 bits implicated by dot field
• Exponent bias only exist in sub-normal format as 23
• Zero is 0b0'0000'000 without negative zero
• Infinity is 0bS'11'0111'1
• NaN is 0b1'0000'000

License

The en_dtypes source code is licensed under the Apache 2.0 license (see LICENSE). Pre-compiled wheels are built with the EIGEN project, which is released under the MPL 2.0 license (see LICENSE.eigen). Implemention is drawn on the ml_dtypes project, which is released under the Apache 2.0 license.