jax.numpy.packbits#

jax.numpy.packbits(a,axis=None,bitorder='big')[source]#

Pack array of bits into a uint8 array.

JAX implementation ofnumpy.packbits()

Parameters:

• a (ArrayLike) – N-dimensional array of bits to pack.

• axis (int |None) – optional axis along which to pack bits. If not specified,a willbe flattened.

• bitorder (str) –"big" (default) or"little": specify whether the bit orderis big-endian or little-endian.

Returns:

A uint8 array of packed values.

Return type:

Array

See also

• jax.numpy.unpackbits(): inverse ofpackbits.

Examples

Packing bits in one dimension:

>>>bits=jnp.array([0,0,0,0,0,1,1,1])>>>jnp.packbits(bits)Array([7], dtype=uint8)>>>0b00000111# equivalent bit-wise representation:7

Optionally specifying little-endian convention:

>>>jnp.packbits(bits,bitorder="little")Array([224], dtype=uint8)>>>0b11100000# equivalent bit-wise representation224

If the number of bits is not a multiple of 8, it will be right-paddedwith zeros:

>>>jnp.packbits(jnp.array([1,0,1]))Array([160], dtype=uint8)>>>jnp.packbits(jnp.array([1,0,1,0,0,0,0,0]))Array([160], dtype=uint8)

For a multi-dimensional input, bits may be packed along a specified axis:

>>>a=jnp.array([[1,1,0,1,0,1,0,0,1,0,0,1,0,1,1,0],...[0,1,0,0,0,1,0,1,1,1,0,0,1,1,1,1]])>>>vals=jnp.packbits(a,axis=1)>>>valsArray([[212, 150],       [ 69, 207]], dtype=uint8)

The inverse ofpackbits is provided byunpackbits():

>>>jnp.unpackbits(vals,axis=1)Array([[1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0],       [0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1]], dtype=uint8)