mafaldaramoa / vqe Goto Github PK

Hi,
I don't know if you still care about this project, given that it seems you have finished your masters (congrats!). If you don't care about keeping it up to date, that is perfectly reasonable, but do still please let me know how I can cite this if I end up publishing anything based on this.

If you would like to keep things up to date, I've found the following bug in CIRQ_UCCSD_VQE.ipynb:

Using the newest versions of OF and cirq, a KeyError occurs in the measureString function, which I believe is caused because cirq no longer saves the columns from identity Paulis in the results.data after this section:

if (pauliString != "I"*len(qubits)):
    s = cirq.Simulator()
    results = s.run(circuit,repetitions = repetitions)

It can be fixed by changing the for loop over range(repetitions) to the following:

for j in range(repetitions):
        meas = 1
        non_identities = 0
        for i in range(len(qubits)):
            if (pauliString[i] != "I"):
              
              meas = meas*(1-2*np.array(results.data)[j][non_identities]) # was meas = meas*(1-2*results.data[i][j]), but that failed. I guess Cirq changed how they save results.data
              non_identities += 1 # This was not here, but is necessary because Cirq no longer adds identity matrices to the results.data
        total += meas

Again, you are obviously under no obligation to keep this up to date, and I would love to credit you properly because this has been a great starting point for me in OF and Cirq, so really the main reason I'm posting this is so I can cite this in the future.