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from functools import partial

import numpy as np
from numpy.testing import assert_, run_module_suite

# disable the MC progress bar
import os
os.environ['QUTIP_GRAPHICS'] = "NO"

from qutip import (sigmax, sigmay, sigmaz, sigmam, mesolve, tensor, destroy,
                   identity, steadystate, expect, basis, num)


class TestJCModelEvolution:
    """
    A test class for the QuTiP functions for the evolution of JC model
    """

    def qubit_integrate(self, tlist, psi0, epsilon, delta, g1, g2):

        H = epsilon / 2.0 * sigmaz() + delta / 2.0 * sigmax()

        c_op_list = []

        rate = g1
        if rate > 0.0:
            c_op_list.append(np.sqrt(rate) * sigmam())

        rate = g2
        if rate > 0.0:
            c_op_list.append(np.sqrt(rate) * sigmaz())

        output = mesolve(
            H, psi0, tlist, c_op_list, [sigmax(), sigmay(), sigmaz()])
        expt_list = output.expect[0], output.expect[1], output.expect[2]

        return expt_list[0], expt_list[1], expt_list[2]

    def jc_steadystate(self, N, wc, wa, g, kappa, gamma,
                       pump, psi0, use_rwa, tlist):

        # Hamiltonian
        a = tensor(destroy(N), identity(2))
        sm = tensor(identity(N), destroy(2))

        if use_rwa:
            # use the rotating wave approxiation
            H = wc * a.dag(
            ) * a + wa * sm.dag() * sm + g * (a.dag() * sm + a * sm.dag())
        else:
            H = wc * a.dag() * a + wa * sm.dag() * sm + g * (
                a.dag() + a) * (sm + sm.dag())

        # collapse operators
        c_op_list = []

        n_th_a = 0.0  # zero temperature

        rate = kappa * (1 + n_th_a)
        c_op_list.append(np.sqrt(rate) * a)

        rate = kappa * n_th_a
        if rate > 0.0:
            c_op_list.append(np.sqrt(rate) * a.dag())

        rate = gamma
        if rate > 0.0:
            c_op_list.append(np.sqrt(rate) * sm)

        rate = pump
        if rate > 0.0:
            c_op_list.append(np.sqrt(rate) * sm.dag())

        # find the steady state
        rho_ss = steadystate(H, c_op_list)

        return expect(a.dag() * a, rho_ss), expect(sm.dag() * sm, rho_ss)

    def jc_integrate(self, N, wc, wa, g, kappa, gamma,
                     pump, psi0, use_rwa, tlist):

        # Hamiltonian
        a = tensor(destroy(N), identity(2))
        sm = tensor(identity(N), destroy(2))

        if use_rwa:
            # use the rotating wave approxiation
            H = wc * a.dag() * a + wa * sm.dag() * sm + g * (
                a.dag() * sm + a * sm.dag())
        else:
            H = wc * a.dag() * a + wa * sm.dag() * sm + g * (
                a.dag() + a) * (sm + sm.dag())

        # collapse operators
        c_op_list = []

        n_th_a = 0.0  # zero temperature

        rate = kappa * (1 + n_th_a)
        c_op_list.append(np.sqrt(rate) * a)

        rate = kappa * n_th_a
        if rate > 0.0:
            c_op_list.append(np.sqrt(rate) * a.dag())

        rate = gamma
        if rate > 0.0:
            c_op_list.append(np.sqrt(rate) * sm)

        rate = pump
        if rate > 0.0:
            c_op_list.append(np.sqrt(rate) * sm.dag())

        # evolve and calculate expectation values
        output = mesolve(
            H, psi0, tlist, c_op_list, [a.dag() * a, sm.dag() * sm])
        expt_list = output.expect[0], output.expect[1]
        return expt_list[0], expt_list[1]

    def testQubitDynamics1(self):
        "mesolve: qubit with dissipation"

        epsilon = 0.0 * 2 * np.pi   # cavity frequency
        delta = 1.0 * 2 * np.pi   # atom frequency
        g2 = 0.1
        g1 = 0.0
        psi0 = basis(2, 0)        # initial state
        tlist = np.linspace(0, 5, 200)

        sx, sy, sz = self.qubit_integrate(tlist, psi0, epsilon, delta, g1, g2)

        sx_analytic = np.zeros(np.shape(tlist))
        sy_analytic = -np.sin(2 * np.pi * tlist) * np.exp(-tlist * g2)
        sz_analytic = np.cos(2 * np.pi * tlist) * np.exp(-tlist * g2)

        assert_(max(abs(sx - sx_analytic)) < 0.05)
        assert_(max(abs(sy - sy_analytic)) < 0.05)
        assert_(max(abs(sz - sz_analytic)) < 0.05)

    def testQubitDynamics2(self):
        "mesolve: qubit without dissipation"

        epsilon = 0.0 * 2 * np.pi   # cavity frequency
        delta = 1.0 * 2 * np.pi   # atom frequency
        g2 = 0.0
        g1 = 0.0
        psi0 = basis(2, 0)        # initial state
        tlist = np.linspace(0, 5, 200)

        sx, sy, sz = self.qubit_integrate(tlist, psi0, epsilon, delta, g1, g2)

        sx_analytic = np.zeros(np.shape(tlist))
        sy_analytic = -np.sin(2 * np.pi * tlist) * np.exp(-tlist * g2)
        sz_analytic = np.cos(2 * np.pi * tlist) * np.exp(-tlist * g2)

        assert_(max(abs(sx - sx_analytic)) < 0.05)