Unexpected conversion to Quil of inverse SWAP gate

[andreamari]

Description of the issue

When converting the inverse of a SWAP gate to Quil the result seems wrong.

How to reproduce the issue

from cirq import Circuit, LineQubit, SWAP
from pyquil import Program
from pyquil.simulation.tools import program_unitary


cirq_circuit = cirq.inverse(Circuit(cirq.SWAP(*qreg)))
print("Cirq circuit:")
print(cirq_circuit)
print("Cirq unitary:\n", cirq_circuit.unitary())


quil_circuit = Program(inverse_swap_circuit.to_quil())
print("PyQuil circuit:")
print(quil_circuit)
print("PyQuil unitary:\n", np.round(program_unitary(quil_circuit, 2), 2))

Gives:

Cirq circuit:
0: ───×───
      │
1: ───×───
Cirq unitary:
 [[1.+0.j 0.+0.j 0.+0.j 0.+0.j]
 [0.+0.j 0.+0.j 1.+0.j 0.+0.j]
 [0.+0.j 1.+0.j 0.+0.j 0.+0.j]
 [0.+0.j 0.+0.j 0.+0.j 1.+0.j]]
PyQuil circuit:
PSWAP(-pi) 0 1

PyQuil unitary:
 [[ 1.+0.j  0.+0.j  0.+0.j  0.+0.j]
 [ 0.+0.j  0.+0.j -1.-0.j  0.+0.j]
 [ 0.+0.j -1.-0.j  0.+0.j  0.+0.j]
 [ 0.+0.j  0.+0.j  0.+0.j  1.+0.j]]

Cirq version

0.14.1

[andreamari]

Thanks @vtomole!