Question about output of codercise I.8.3

Codebook
1

In Codercise I.8.3, we are told that " we’ll print the circuit using qml.draw to investigate which operations were actually used under the hood." However, this is the output I see even though my submission was accepted as correct.
image

Here is my code
v = np.array([0.52889389-0.14956775j, 0.67262317+0.49545818j])

dev = qml.device("default.qubit", wires=1)

@qml.qnode(dev)
def prepare_state(state=v): qml.MottonenStatePreparation(state_vector=state, wires=0) return qml.state()

prepare_state(state=v) print() print(qml.draw(prepare_state)(v))

2

Thank you for pointing this out @Kamal_Mohamed!

We should add expansion_strategy='device' in the qml.draw statement in order to see the gates.

Would you like to open an issue about this in the Codebook GitHub repo?

3

For sure. Here is the link to it.

4

Thank you @Kamal_Mohamed!

5

Error: ufunc ‘isfinite’ not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ‘‘safe’’. I am getting this error

v = np.array([0.52889389-0.14956775j, 0.67262317+0.49545818j])

##################
# YOUR CODE HERE #
##################

# CREATE A DEVICE


# CONSTRUCT A QNODE THAT USES qml.MottonenStatePreparation
# TO PREPARE A QUBIT IN STATE V, AND RETURN THE STATE


def prepare_state(state=v):
    qml.MottonenStatePreparation(state,wires = 0)
    
    return qml.state()

# This will draw the quantum circuit and allow you to inspect the output gates
print(prepare_state(v))
print()
print(qml.draw(prepare_state, expansion_strategy='device')(v))
6

Hey @SUDHIR_KUMAR_SAHOO, welcome to the forum!

You need to create a device and decorate your prepare_state function with @qml.qnode :slight_smile:. This part of our documentation is a good resource to look at in order to understand what’s going on here: Quantum circuits — PennyLane 0.34.0 documentation

Let me know if that helps!