def test_swap_gate():
"""Test the SWAP gate."""
swap_gate_matrix = Matrix(((1,0,0,0),(0,0,1,0),(0,1,0,0),(0,0,0,1)))
assert represent(SwapGate(1,0).decompose(), nqubits=2) == swap_gate_matrix
assert qapply(SwapGate(1,3)*Qubit('0010')) == Qubit('1000')
nqubits = 4
for i in range(nqubits):
for j in range(i):
assert represent(SwapGate(i,j), nqubits=nqubits) ==\
represent(SwapGate(i,j).decompose(), nqubits=nqubits)
def test_quantum_fourier():
assert QFT(0,3).decompose() == SwapGate(0,2)*HadamardGate(0)*CGate((0,), PhaseGate(1))\
*HadamardGate(1)*CGate((0,), TGate(2))*CGate((1,), PhaseGate(2))*HadamardGate(2)
assert IQFT(0,3).decompose() == HadamardGate(2)*CGate((1,), RkGate(2,-2))*CGate((0,),RkGate(2,-3))\
*HadamardGate(1)*CGate((0,), RkGate(1,-2))*HadamardGate(0)*SwapGate(0,2)
assert represent(QFT(0,3), nqubits=3)\
== Matrix([[exp(2*pi*I/8)**(i*j%8)/sqrt(8) for i in range(8)] for j in range(8)])
assert QFT(0, 4).decompose() #non-trivial decomposition
assert qapply(QFT(0,3).decompose()*Qubit(0,0,0)).expand() ==\
qapply(HadamardGate(0)*HadamardGate(1)*HadamardGate(2)*Qubit(0,0,0)).expand()
def decompose(self):
"""Decomposes IQFT into elementary gates."""
start = self.args[0]
finish = self.args[1]
circuit = 1
for i in range((finish-start)//2):
circuit = SwapGate(i+start, finish-i-1)*circuit
for level in range(start, finish):
for i in reversed(range(level-start)):
circuit = CGate(level-i-1, RkGate(level, -i-2))*circuit
circuit = HadamardGate(level)*circuit
return circuit
def decompose(self):
"""Decomposes QFT into elementary gates."""
start = self.label[0]
finish = self.label[1]
circuit = 1
for level in reversed(range(start, finish)):
circuit = HadamardGate(level) * circuit
for i in range(level - start):
circuit = CGate(level - i - 1, RkGate(level, i + 2)) * circuit
#FIXME-py3k: TypeError: 'Rational' object cannot be interpreted as an integer
for i in range((finish - start) / 2):
circuit = SwapGate(i + start, finish - i - 1) * circuit
return circuit
def test_sympy__physics__quantum__gate__SwapGate():
from sympy.physics.quantum.gate import SwapGate
assert _test_args(SwapGate(0, 1))