flopscope.

flopscope.numpy.packbits

fnp.packbits(a, *args, **kwargs)[flopscope source]

Packs the elements of a binary-valued array into bits in a uint8 array.

Adapted from NumPy docs np.packbits

Areacore
Typecustom
NumPy Refnp.packbits
Cost
per-operation
Flopscope Context

Pack elements of array into bits. Cost: numel(input).

The result is padded to full bytes by inserting zero bits at the end.

Parameters

a:array_like

An array of integers or booleans whose elements should be packed to bits.

axis:int, optional

The dimension over which bit-packing is done. None implies packing the flattened array.

bitorder:{'big', 'little'}, optional

The order of the input bits. 'big' will mimic bin(val), [0, 0, 0, 0, 0, 0, 1, 1] => 3 = 0b00000011, 'little' will reverse the order so [1, 1, 0, 0, 0, 0, 0, 0] => 3. Defaults to 'big'.

Returns

packed:ndarray

Array of type uint8 whose elements represent bits corresponding to the logical (0 or nonzero) value of the input elements. The shape of packed has the same number of dimensions as the input (unless axis is None, in which case the output is 1-D).

See also

Examples

>>> import flopscope.numpy as fnp
>>> a = flops.array([[[1,0,1],
... [0,1,0]],
... [[1,1,0],
... [0,0,1]]])
>>> b = flops.packbits(a, axis=-1)
>>> b
array([[[160],
        [ 64]],
       [[192],
        [ 32]]], dtype=uint8)

Note that in binary 160 = 1010 0000, 64 = 0100 0000, 192 = 1100 0000, and 32 = 0010 0000.