pyqubo.Array.matmul¶

Array.
matmul
(other)[source]¶ Returns a matrix product of two arrays.
Note
You can use operator symbol ‘@’ instead of
matmul()
in Python 3.5 or later version.>>> from pyqubo import Array >>> array_a = Array.create('a', shape=(2, 4), vartype='BINARY') >>> array_b = Array.create('b', shape=(4, 3), vartype='BINARY') >>> array_a @ array_b == array_a.matmul(array_b) True
Parameters: other ( Array
/numpy.ndarray
/list) –Returns: Array
/Express
Example
Matrix product of two arrays falls into 3 patterns.
1. If either of the arguments is 1D array, it is treated as a matrix where one is added to its dimension.
>>> from pyqubo import Array, Binary >>> array_a = Array([[Binary('a'), Binary('b')], [Binary('c'), Binary('d')]]) >>> array_b = Array([Binary('e'), Binary('f')]) >>> array_a.matmul(array_b) Array([((Binary(a)*Binary(e))+(Binary(b)*Binary(f))), ((Binary(c)*Binary(e))+(Binary(d)*Binary(f)))])
 If both arguments are 2D array, conventional matrix product is calculated.
>>> array_a = Array([[Binary('a'), Binary('b')], [Binary('c'), Binary('d')]]) >>> array_b = Array([[Binary('e'), Binary('f')], [Binary('g'), Binary('h')]]) >>> array_a.matmul(array_b) Array([[((Binary(a)*Binary(e))+(Binary(b)*Binary(g))), ((Binary(a)*Binary(f))+(Binary(b)*Binary(h)))], [((Binary(c)*Binary(e))+(Binary(d)*Binary(g))), ((Binary(c)*Binary(f))+(Binary(d)*Binary(h)))]])
3. If either argument is ND (where N > 2), it is treated as an array whose element is a 2D matrix of last two indices. In this example, array_a is treated as if it is a vector whose elements are two matrices of shape (2, 3).
>>> array_a = Array.create('a', shape=(2, 2, 3), vartype='BINARY') >>> array_b = Array.create('b', shape=(3, 2), vartype='BINARY') >>> (array_a @ array_b)[0] == array_a[0].matmul(array_b) True