Using qml.draw for qml.templates.ApproxTimeEvolution

PennyLane Help
1

I try to plot the circuit found from qml.templates.ApproxTimeEvolution using both qml.draw and qml.draw_mpl, but it is only plotted as a black box as shown below:

Screenshot%20from%202022-08-26%2015-00-01

Any idea why is that happening?

Here is the code:

import pennylane as qml
from pennylane.templates import ApproxTimeEvolution

n_wires = 2
wires = range(n_wires)

coeffs = [1, 1]
obs = [qml.PauliX(0), qml.PauliX(1)]
hamiltonian1 = qml.Hamiltonian(coeffs, obs)

dev = qml.device(‘default.qubit’, wires=2)
@qml.qnode(dev)
def circuit(time):
qml.templates.ApproxTimeEvolution(hamiltonian1, time, 1)
return [qml.expval(qml.PauliZ(wires=i)) for i in wires]

given_time=1
circuit(given_time)

print (qml.draw(circuit)(given_time))
qml.draw_mpl(circuit)(given_time)

2

Hi @Aikaterini_Katerina, welcome to the forum!

Maybe you can try:
qml.draw_mpl(circuit, expansion_strategy="device")(given_time)
or
qml. ApproxTimeEvolution.decomposition(wires=wires)

Do any of these options work?