Added qiskit script with transpile

from qiskit.aqua.operators import (X, Y, Z, I, CX, H, ListOp, CircuitOp, Zero, EvolutionFactory,

                                   EvolvedOp, PauliTrotterEvolution, QDrift, Trotter, Suzuki)

from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit

from qiskit.compiler import transpile

import warnings

warnings.filterwarnings('ignore', category=DeprecationWarning)

import time

def X_op(idxs, n_qubits):

  op = None

  if 0 in idxs:

    op = X

  else:

    op = I

  for i in range(1, n_qubits):

    if (i in idxs):

      op ^= X

    else:

      op ^= I

  return op

def Z_op(idxs, n_qubits):

  op = None

  if 0 in idxs:

    op = Z

  else:

    op = I

  for i in range(1, n_qubits):

    if (i in idxs):

      op ^= Z

    else:

      op ^= I

  return op

def heisenberg_ham(n_qubits):

  Jz = 1.0

  h = 1.0

  H = -h * X_op([0], n_qubits)

  for i in range(1, n_qubits):

    H = H - h * X_op([i], n_qubits)

  for i in range(n_qubits - 1):

    H = H - Jz * (Z_op([i, i + 1], n_qubits))

  return H

n_qubits = [10, 20, 50, 100]

nbSteps = 100

def trotter_circ(q, exp_args, n_steps):

  qc = QuantumCircuit(q)

  for i in range(n_steps):

    for sub_op in exp_args:

      qc += PauliTrotterEvolution().convert(EvolvedOp(sub_op)).to_circuit()

  return qc

n_qubits = [5, 10, 20, 50, 100]

nbSteps = 100

for nbQubits in n_qubits:

  ham_op = heisenberg_ham(nbQubits)

  q = QuantumRegister(nbQubits, 'q')

  start = time.time()

  comp = trotter_circ(q, ham_op.oplist, nbSteps)

  comp = transpile(comp, optimization_level=3)

  end = time.time()

  ops_count = comp.count_ops()

  num_gates = 0

  # Count gates except identity

  for gate_name in ops_count:

    if gate_name != "id":

      num_gates += ops_count[gate_name]

  print("n_qubits =", nbQubits, "; n instructions =", num_gates, "; Kernel eval time:", end - start, " [secs]")

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