qrisp.QuantumCircuit.get_unitary#

QuantumCircuit.get_unitary(decimals=-1)[source]#

Acquires the unitary matrix of the given QuantumCircuit as a Numpy array.

This method also works with abstract parameters. In this case a Numpy array with Sympy entries is returned.

Parameters:

decimalsinteger, optional: The amount of decimals to be rounded to. By default, the full precision is returned.

Returns:

numpy.ndarray: The unitary matrix as a numpy array.

Examples

We synthesize a controlled phase gate and inspect the unitary:

>>> from qrisp import QuantumCircuit
>>> import numpy as np
>>> qc = QuantumCircuit(2)
>>> phi = np.pi
>>> qc.p(phi/2, 0)
>>> qc.p(phi/2, 1)
>>> qc.cx(0,1)
>>> qc.p(-phi/2, 1)
>>> qc.cx(0,1)
>>> qc.get_unitary(decimals = 4)
array([[ 1.+0.j,  0.+0.j,  0.+0.j,  0.+0.j],
       [ 0.+0.j,  1.+0.j,  0.+0.j,  0.+0.j],
       [ 0.+0.j,  0.+0.j,  1.+0.j,  0.+0.j],
       [ 0.+0.j,  0.+0.j,  0.+0.j, -1.+0.j]], dtype=complex64)

We now synthesize the exact same QuantumCircuit but this time phi is a Sympy symbol.

>>> from sympy import Symbol
>>> qc = QuantumCircuit(2)
>>> phi = Symbol("phi")
>>> qc.p(phi/2, 0)
>>> qc.p(phi/2, 1)
>>> qc.cx(0,1)
>>> qc.p(-phi/2, 1)
>>> qc.cx(0,1)
>>> qc.get_unitary(decimals = 4)
array([[1, 0, 0, 0],
       [0, 1, 0, 0],
       [0, 0, 1, 0],
       [0, 0, 0, exp(I*phi)]], dtype=object)