Python numpy.cosh() Examples

def psi2c2c3(self, psi0):

        c2 = np.zeros(len(psi0))
        c3 = np.zeros(len(psi0))

        psi12 = np.sqrt(np.abs(psi0))
        pos = psi0 >= 0
        neg = psi0 < 0
        if np.any(pos):
            c2[pos] = (1 - np.cos(psi12[pos]))/psi0[pos]
            c3[pos] = (psi12[pos] - np.sin(psi12[pos]))/psi12[pos]**3.
        if any(neg):
            c2[neg] = (1 - np.cosh(psi12[neg]))/psi0[neg]
            c3[neg] = (np.sinh(psi12[neg]) - psi12[neg])/psi12[neg]**3.

        tmp = c2+c3 == 0
        if any(tmp):
            c2[tmp] = 1./2.
            c3[tmp] = 1./6.

        return c2,c3 

def c2c3(psi):  # Stumpff functions definitions

    c2, c3 = 0, 0

    if np.any(psi > 1e-6):
        c2 = (1 - np.cos(np.sqrt(psi))) / psi
        c3 = (np.sqrt(psi) - np.sin(np.sqrt(psi))) / np.sqrt(psi ** 3)

    if np.any(psi < -1e-6):
        c2 = (1 - np.cosh(np.sqrt(-psi))) / psi
        c3 = (np.sinh(np.sqrt(-psi)) - np.sqrt(-psi)) / np.sqrt(-psi ** 3)

    if np.any(abs(psi) <= 1e-6):
        c2 = 0.5
        c3 = 1. / 6.

    return c2, c3 

def cheb1ap(N, rp):
    """Return (z,p,k) zero, pole, gain for Nth order Chebyshev type I lowpass
    analog filter prototype with `rp` decibels of ripple in the passband.

    The filter's angular (e.g. rad/s) cutoff frequency is normalized to 1,
    defined as the point at which the gain first drops below -`rp`.

    """
    z = numpy.array([])
    eps = numpy.sqrt(10 ** (0.1 * rp) - 1.0)
    n = numpy.arange(1, N + 1)
    mu = 1.0 / N * numpy.log((1.0 + numpy.sqrt(1 + eps * eps)) / eps)
    theta = pi / 2.0 * (2 * n - 1.0) / N
    p = (-numpy.sinh(mu) * numpy.sin(theta) +
         1j * numpy.cosh(mu) * numpy.cos(theta))
    k = numpy.prod(-p, axis=0).real
    if N % 2 == 0:
        k = k / sqrt((1 + eps * eps))
    return z, p, k 

def cheb2ap(N, rs):
    """Return (z,p,k) zero, pole, gain for Nth order Chebyshev type II lowpass
    analog filter prototype with `rs` decibels of ripple in the stopband.

    The filter's angular (e.g. rad/s) cutoff frequency is normalized to 1,
    defined as the point at which the gain first reaches -`rs`.

    """
    de = 1.0 / sqrt(10 ** (0.1 * rs) - 1)
    mu = arcsinh(1.0 / de) / N

    if N % 2:
        n = numpy.concatenate((numpy.arange(1, N - 1, 2),
                               numpy.arange(N + 2, 2 * N, 2)))
    else:
        n = numpy.arange(1, 2 * N, 2)

    z = conjugate(1j / cos(n * pi / (2.0 * N)))
    p = exp(1j * (pi * numpy.arange(1, 2 * N, 2) / (2.0 * N) + pi / 2.0))
    p = sinh(mu) * p.real + 1j * cosh(mu) * p.imag
    p = 1.0 / p
    k = (numpy.prod(-p, axis=0) / numpy.prod(-z, axis=0)).real
    return z, p, k 

def test_two_mode_squeezing(self, setup_backend, r, p, cutoff, pure, tol):
        r""" Test two-mode squeezing on vacuum-state for both pure states and
        mixed states with the amplitude given by
	        :math:`\delta_{kl} \frac{e^{in\phi} \tanh^n{r}}{\cosh{r}}`
        """

        backend = setup_backend(2)
        backend.two_mode_squeeze(r, p, 0, 1)

        state = backend.state()

        if pure:
            for k in it.product(range(cutoff), repeat=2):
                tmsv = get_amplitude(k, r, p)
                assert np.allclose(state.data[k], tmsv, atol=tol, rtol=0)
        else:
            for k in it.product(range(cutoff), repeat=2):
                for l in it.product(range(cutoff), repeat=2):
                    t = (k[0], l[0], k[1], l[1])
                    tmsv2 = get_amplitude(k, r, p) * np.conj(get_amplitude(l, r, p))

                    assert np.allclose(state.data[t], tmsv2, atol=tol, rtol=0) 

def testAcoshFunction(self):
        ma5 = MovingAverage(5, 'close')
        holder = Acosh(ma5)

        sampleClose = np.cosh(self.sampleClose)

        for i, close in enumerate(sampleClose):
            data = {'close': close}
            ma5.push(data)
            holder.push(data)

            expected = math.acosh(ma5.result())
            calculated = holder.result()
            self.assertAlmostEqual(calculated, expected, 12, "at index {0:d}\n"
                                                             "expected:   {1:f}\n"
                                                             "calculated: {2:f}".format(i, expected, calculated)) 

def test_squeezed_coherent(self, setup_backend, hbar, batch_size, tol):
        """Test squeezed coherent state has correct mean and variance"""
        # quadrature rotation angle
        backend = setup_backend(1)
        qphi = 0.78

        backend.prepare_displaced_squeezed_state(np.abs(a), np.angle(a), r, phi, 0)

        state = backend.state()
        res = np.array(state.quad_expectation(0, phi=qphi)).T

        xphi_mean = (a.real * np.cos(qphi) + a.imag * np.sin(qphi)) * np.sqrt(2 * hbar)
        xphi_var = (np.cosh(2 * r) - np.cos(phi - 2 * qphi) * np.sinh(2 * r)) * hbar / 2
        res_exact = np.array([xphi_mean, xphi_var])

        if batch_size is not None:
            res_exact = np.tile(res_exact, batch_size)

        assert np.allclose(res.flatten(), res_exact.flatten(), atol=tol, rtol=0) 

def test_squeezed_coherent(setup_backend, hbar, tol):
    """Test Wigner function for a squeezed coherent state
    matches the analytic result"""
    backend = setup_backend(1)
    backend.prepare_coherent_state(np.abs(A), np.angle(A), 0)
    backend.squeeze(R, PHI, 0)

    state = backend.state()
    W = state.wigner(0, XVEC, XVEC)
    rot = rotm(PHI / 2)

    # exact wigner function
    alpha = A * np.cosh(R) - np.conjugate(A) * np.exp(1j * PHI) * np.sinh(R)
    mu = np.array([alpha.real, alpha.imag]) * np.sqrt(2 * hbar)
    cov = np.diag([np.exp(-2 * R), np.exp(2 * R)])
    cov = np.dot(rot, np.dot(cov, rot.T)) * hbar / 2.0
    Wexact = wigner(GRID, mu, cov)

    assert np.allclose(W, Wexact, atol=0.01, rtol=0) 

def test_swish_grad(self):
        def swish_grad(x, beta):
            return (
                beta * (2 - beta * x * np.tanh(beta * x / 2)) / (1 + np.cosh(beta * x))
            )

        x = testing_utils.generate_real_values_with_zeros(shape=(8, 3, 3, 16))
        tf_x = tf.Variable(x)
        with tf.GradientTape() as tape:
            activation = lq.quantizers.SwishSign()(tf_x)
        grad = tape.gradient(activation, tf_x)
        np.testing.assert_allclose(grad.numpy(), swish_grad(x, beta=5.0))

        with tf.GradientTape() as tape:
            activation = lq.quantizers.SwishSign(beta=10.0)(tf_x)
        grad = tape.gradient(activation, tf_x)
        np.testing.assert_allclose(grad.numpy(), swish_grad(x, beta=10.0)) 

def test_displaced_squeezed_state_fock(self, r_d, phi_d, r_s, phi_s, hbar, cutoff, tol):
        """test displaced squeezed state returns correct Fock basis state vector"""
        state = utils.displaced_squeezed_state(r_d, phi_d, r_s, phi_s, basis="fock", fock_dim=cutoff, hbar=hbar)
        a = r_d * np.exp(1j * phi_d)

        if r_s == 0:
            pytest.skip("test only non-zero squeezing")

        n = np.arange(cutoff)
        gamma = a * np.cosh(r_s) + np.conj(a) * np.exp(1j * phi_s) * np.sinh(r_s)
        coeff = np.diag(
            (0.5 * np.exp(1j * phi_s) * np.tanh(r_s)) ** (n / 2) / np.sqrt(fac(n) * np.cosh(r_s))
        )

        expected = H(gamma / np.sqrt(np.exp(1j * phi_s) * np.sinh(2 * r_s)), coeff)
        expected *= np.exp(
            -0.5 * np.abs(a) ** 2 - 0.5 * np.conj(a) ** 2 * np.exp(1j * phi_s) * np.tanh(r_s)
        )

        assert np.allclose(state, expected, atol=tol, rtol=0) 

def test_displaced_squeezed_state_gaussian(self, r_d, phi_d, r_s, phi_s, hbar, tol):
        """test displaced squeezed state returns correct means and covariance"""
        means, cov = utils.displaced_squeezed_state(r_d, phi_d, r_s, phi_s, basis="gaussian", hbar=hbar)

        a = r_d * np.exp(1j * phi_d)
        means_expected = np.array([[a.real, a.imag]]) * np.sqrt(2 * hbar)
        cov_expected = (hbar / 2) * np.array(
            [
                [
                    np.cosh(2 * r_s) - np.cos(phi_s) * np.sinh(2 * r_s),
                    -2 * np.cosh(r_s) * np.sin(phi_s) * np.sinh(r_s),
                ],
                [
                    -2 * np.cosh(r_s) * np.sin(phi_s) * np.sinh(r_s),
                    np.cosh(2 * r_s) + np.cos(phi_s) * np.sinh(2 * r_s),
                ],
            ]
        )

        assert np.allclose(means, means_expected, atol=tol, rtol=0)
        assert np.allclose(cov, cov_expected, atol=tol, rtol=0) 

def test_squeezed_state_gaussian(self, r, phi, hbar, tol):
        """test squeezed state returns correct means and covariance"""
        means, cov = utils.squeezed_state(r, phi, basis="gaussian", hbar=hbar)

        cov_expected = (hbar / 2) * np.array(
            [
                [
                    np.cosh(2 * r) - np.cos(phi) * np.sinh(2 * r),
                    -2 * np.cosh(r) * np.sin(phi) * np.sinh(r),
                ],
                [
                    -2 * np.cosh(r) * np.sin(phi) * np.sinh(r),
                    np.cosh(2 * r) + np.cos(phi) * np.sinh(2 * r),
                ],
            ]
        )

        assert np.all(means == np.zeros([2]))
        assert np.allclose(cov, cov_expected, atol=tol, rtol=0) 

def fields(x,y,z, kx, ky, kz, B0):
    k1 =  -B0*kx/ky
    k2 = -B0*kz/ky
    kx_x = kx*x
    ky_y = ky*y
    kz_z = kz*z
    cosx = np.cos(kx_x)
    sinhy = np.sinh(ky_y)
    cosz = np.cos(kz_z)
    Bx = k1*np.sin(kx_x)*sinhy*cosz #// here kx is only real
    By = B0*cosx*np.cosh(ky_y)*cosz
    Bz = k2*cosx*sinhy*np.sin(kz_z)
    #Bx = ne.evaluate("k1*sin(kx*x)*sinhy*cosz")
    #By = ne.evaluate("B0*cosx*cosh(ky*y)*cosz")
    #Bz = ne.evaluate("k2*cosx*sinhy*sin(kz*z)")
    return Bx, By, Bz 

def TMS(r, phi):
    """Two-mode squeezing.

    Args:
        r (float): squeezing magnitude
        phi (float): rotation parameter

    Returns:
        array: symplectic transformation matrix
    """
    cp = np.cos(phi)
    sp = np.sin(phi)
    ch = np.cosh(r)
    sh = np.sinh(r)

    S = np.array(
        [
            [ch, cp * sh, 0, sp * sh],
            [cp * sh, ch, sp * sh, 0],
            [0, sp * sh, ch, -cp * sh],
            [sp * sh, 0, -cp * sh, ch],
        ]
    )

    return S 

def _squeezing(r, phi, mode, num_modes):
    """Squeezing in the phase space.

    Args:
        r (float): squeezing magnitude
        phi (float): rotation parameter
        mode (int): mode it is applied to
        num_modes (int): total number of modes in the system

    Returns:
        array: symplectic transformation matrix
    """
    cp = np.cos(phi)
    sp = np.sin(phi)
    ch = np.cosh(r)
    sh = np.sinh(r)

    S = np.array([[ch - cp * sh, -sp * sh], [-sp * sh, ch + cp * sh]])

    return expand(S, mode, num_modes) 

def TMS(r, phi):
    """Two-mode squeezing.

    Args:
        r (float): squeezing magnitude
        phi (float): rotation parameter

    Returns:
        array: symplectic transformation matrix
    """
    cp = np.cos(phi)
    sp = np.sin(phi)
    ch = np.cosh(r)
    sh = np.sinh(r)

    S = np.array(
        [
            [ch, cp * sh, 0, sp * sh],
            [cp * sh, ch, sp * sh, 0],
            [0, sp * sh, ch, -cp * sh],
            [sp * sh, 0, -cp * sh, ch],
        ]
    )

    return S 

def test_CXgate_decomp_equal(self, setup_eng, s, tol):
        """Tests that the CXgate gives the same transformation as its decomposition."""
        eng, prog = setup_eng(2)

        r = np.arcsinh(-s / 2)
        y = -1 / np.cosh(r)
        x = -np.tanh(r)
        theta = np.arctan2(y, x) / 2

        with prog.context as q:
            ops.CXgate(s) | q
            # run decomposition with reversed arguments
            ops.BSgate(-(np.pi / 2 + theta), 0) | q
            ops.Sgate(r, np.pi) | q[0]
            ops.Sgate(r, 0) | q[1]
            ops.BSgate(-theta, 0) | q

        eng.run(prog)
        assert np.all(eng.backend.is_vacuum(tol)) 

def test_squeezed_state_fock(self, r, phi, cutoff, hbar, tol):
        """test squeezed state returns correct Fock basis state vector"""
        state = utils.squeezed_state(r, phi, basis="fock", fock_dim=cutoff, hbar=hbar)

        n = np.arange(cutoff)
        kets = (np.sqrt(fac(2 * (n // 2))) / (2 ** (n // 2) * fac(n // 2))) * (
            -np.exp(1j * phi) * np.tanh(r)
        ) ** (n // 2)
        expected = np.where(n % 2 == 0, np.sqrt(1 / np.cosh(r)) * kets, 0)

        assert np.allclose(state, expected, atol=tol, rtol=0) 

def P_phi(self, phi):
        if self.model == 'von_Mises':
            return self.P_phi_prefac * np.cosh(self.kzeta*np.cos(phi - self.phi0))  
        elif self.model == 'boxcar':
            return self.P_phi_prefac * (1.0 - ((np.pi/(2.0*(1.0 + self.kzeta)) < (phi - self.phi0) % np.pi) & ((phi - self.phi0) % np.pi < np.pi - np.pi/(2.0*(1.0 + self.kzeta)))))
        elif self.model == 'dipole':
            return self.P_phi_prefac * (1.0 + self.kzeta*np.sin(phi - self.phi0)**2)**(-(self.scatt_alpha + 2.0)/2.0) 

def test_testUfuncRegression(self):
        f_invalid_ignore = ['sqrt', 'arctanh', 'arcsin', 'arccos',
                'arccosh', 'arctanh', 'log', 'log10', 'divide',
                'true_divide', 'floor_divide', 'remainder', 'fmod']
        for f in ['sqrt', 'log', 'log10', 'exp', 'conjugate',
                'sin', 'cos', 'tan',
                'arcsin', 'arccos', 'arctan',
                'sinh', 'cosh', 'tanh',
                'arcsinh',
                'arccosh',
                'arctanh',
                'absolute', 'fabs', 'negative',
                # 'nonzero', 'around',
                'floor', 'ceil',
                # 'sometrue', 'alltrue',
                'logical_not',
                'add', 'subtract', 'multiply',
                'divide', 'true_divide', 'floor_divide',
                'remainder', 'fmod', 'hypot', 'arctan2',
                'equal', 'not_equal', 'less_equal', 'greater_equal',
                'less', 'greater',
                'logical_and', 'logical_or', 'logical_xor',
                ]:
            try:
                uf = getattr(umath, f)
            except AttributeError:
                uf = getattr(fromnumeric, f)
            mf = getattr(np.ma, f)
            args = self.d[:uf.nin]
            with np.errstate():
                if f in f_invalid_ignore:
                    np.seterr(invalid='ignore')
                if f in ['arctanh', 'log', 'log10']:
                    np.seterr(divide='ignore')
                ur = uf(*args)
                mr = mf(*args)
            self.assertTrue(eq(ur.filled(0), mr.filled(0), f))
            self.assertTrue(eqmask(ur.mask, mr.mask)) 

def test_testUfuncs1(self):
        # Test various functions such as sin, cos.
        (x, y, a10, m1, m2, xm, ym, z, zm, xf, s) = self.d
        assert_(eq(np.cos(x), cos(xm)))
        assert_(eq(np.cosh(x), cosh(xm)))
        assert_(eq(np.sin(x), sin(xm)))
        assert_(eq(np.sinh(x), sinh(xm)))
        assert_(eq(np.tan(x), tan(xm)))
        assert_(eq(np.tanh(x), tanh(xm)))
        with np.errstate(divide='ignore', invalid='ignore'):
            assert_(eq(np.sqrt(abs(x)), sqrt(xm)))
            assert_(eq(np.log(abs(x)), log(xm)))
            assert_(eq(np.log10(abs(x)), log10(xm)))
        assert_(eq(np.exp(x), exp(xm)))
        assert_(eq(np.arcsin(z), arcsin(zm)))
        assert_(eq(np.arccos(z), arccos(zm)))
        assert_(eq(np.arctan(z), arctan(zm)))
        assert_(eq(np.arctan2(x, y), arctan2(xm, ym)))
        assert_(eq(np.absolute(x), absolute(xm)))
        assert_(eq(np.equal(x, y), equal(xm, ym)))
        assert_(eq(np.not_equal(x, y), not_equal(xm, ym)))
        assert_(eq(np.less(x, y), less(xm, ym)))
        assert_(eq(np.greater(x, y), greater(xm, ym)))
        assert_(eq(np.less_equal(x, y), less_equal(xm, ym)))
        assert_(eq(np.greater_equal(x, y), greater_equal(xm, ym)))
        assert_(eq(np.conjugate(x), conjugate(xm)))
        assert_(eq(np.concatenate((x, y)), concatenate((xm, ym))))
        assert_(eq(np.concatenate((x, y)), concatenate((x, y))))
        assert_(eq(np.concatenate((x, y)), concatenate((xm, y))))
        assert_(eq(np.concatenate((x, y, x)), concatenate((x, ym, x)))) 

def _two_mode_squeezing(r, phi, modes, num_modes):
    """Two mode squeezing in the phase space.

    Args:
        r (float): squeezing magnitude
        phi (float): rotation parameter
        modes (list[int]): modes it is applied to
        num_modes (int): total number of modes in the system

    Returns:
        array: symplectic transformation matrix
    """
    cp = np.cos(phi)
    sp = np.sin(phi)
    ch = np.cosh(r)
    sh = np.sinh(r)

    S = np.array(
        [
            [ch, cp * sh, 0, sp * sh],
            [cp * sh, ch, sp * sh, 0],
            [0, sp * sh, ch, -cp * sh],
            [sp * sh, 0, -cp * sh, ch],
        ]
    )

    return expand(S, modes, num_modes) 

def test_testUfuncRegression(self):
        f_invalid_ignore = [
            'sqrt', 'arctanh', 'arcsin', 'arccos',
            'arccosh', 'arctanh', 'log', 'log10', 'divide',
            'true_divide', 'floor_divide', 'remainder', 'fmod']
        for f in ['sqrt', 'log', 'log10', 'exp', 'conjugate',
                  'sin', 'cos', 'tan',
                  'arcsin', 'arccos', 'arctan',
                  'sinh', 'cosh', 'tanh',
                  'arcsinh',
                  'arccosh',
                  'arctanh',
                  'absolute', 'fabs', 'negative',
                  'floor', 'ceil',
                  'logical_not',
                  'add', 'subtract', 'multiply',
                  'divide', 'true_divide', 'floor_divide',
                  'remainder', 'fmod', 'hypot', 'arctan2',
                  'equal', 'not_equal', 'less_equal', 'greater_equal',
                  'less', 'greater',
                  'logical_and', 'logical_or', 'logical_xor']:
            try:
                uf = getattr(umath, f)
            except AttributeError:
                uf = getattr(fromnumeric, f)
            mf = getattr(np.ma, f)
            args = self.d[:uf.nin]
            with np.errstate():
                if f in f_invalid_ignore:
                    np.seterr(invalid='ignore')
                if f in ['arctanh', 'log', 'log10']:
                    np.seterr(divide='ignore')
                ur = uf(*args)
                mr = mf(*args)
            assert_(eq(ur.filled(0), mr.filled(0), f))
            assert_(eqmask(ur.mask, mr.mask)) 

def test_basic_ufuncs(self):
        # Test various functions such as sin, cos.
        (x, y, a10, m1, m2, xm, ym, z, zm, xf) = self.d
        assert_equal(np.cos(x), cos(xm))
        assert_equal(np.cosh(x), cosh(xm))
        assert_equal(np.sin(x), sin(xm))
        assert_equal(np.sinh(x), sinh(xm))
        assert_equal(np.tan(x), tan(xm))
        assert_equal(np.tanh(x), tanh(xm))
        assert_equal(np.sqrt(abs(x)), sqrt(xm))
        assert_equal(np.log(abs(x)), log(xm))
        assert_equal(np.log10(abs(x)), log10(xm))
        assert_equal(np.exp(x), exp(xm))
        assert_equal(np.arcsin(z), arcsin(zm))
        assert_equal(np.arccos(z), arccos(zm))
        assert_equal(np.arctan(z), arctan(zm))
        assert_equal(np.arctan2(x, y), arctan2(xm, ym))
        assert_equal(np.absolute(x), absolute(xm))
        assert_equal(np.angle(x + 1j*y), angle(xm + 1j*ym))
        assert_equal(np.angle(x + 1j*y, deg=True), angle(xm + 1j*ym, deg=True))
        assert_equal(np.equal(x, y), equal(xm, ym))
        assert_equal(np.not_equal(x, y), not_equal(xm, ym))
        assert_equal(np.less(x, y), less(xm, ym))
        assert_equal(np.greater(x, y), greater(xm, ym))
        assert_equal(np.less_equal(x, y), less_equal(xm, ym))
        assert_equal(np.greater_equal(x, y), greater_equal(xm, ym))
        assert_equal(np.conjugate(x), conjugate(xm)) 

def test_testUfuncRegression(self):
        # Tests new ufuncs on MaskedArrays.
        for f in ['sqrt', 'log', 'log10', 'exp', 'conjugate',
                  'sin', 'cos', 'tan',
                  'arcsin', 'arccos', 'arctan',
                  'sinh', 'cosh', 'tanh',
                  'arcsinh',
                  'arccosh',
                  'arctanh',
                  'absolute', 'fabs', 'negative',
                  'floor', 'ceil',
                  'logical_not',
                  'add', 'subtract', 'multiply',
                  'divide', 'true_divide', 'floor_divide',
                  'remainder', 'fmod', 'hypot', 'arctan2',
                  'equal', 'not_equal', 'less_equal', 'greater_equal',
                  'less', 'greater',
                  'logical_and', 'logical_or', 'logical_xor',
                  ]:
            try:
                uf = getattr(umath, f)
            except AttributeError:
                uf = getattr(fromnumeric, f)
            mf = getattr(numpy.ma.core, f)
            args = self.d[:uf.nin]
            ur = uf(*args)
            mr = mf(*args)
            assert_equal(ur.filled(0), mr.filled(0), f)
            assert_mask_equal(ur.mask, mr.mask, err_msg=f) 

def test_displaced_squeezed_mean_photon_gradient(self, setup_eng, cutoff, tol, batch_size):
        """Test whether the gradient of the mean photon number of a displaced squeezed
        state is correct.

        .. note::

            As this test contains multiple gates being applied to the program,
            this test will fail in TensorFlow 2.1 due to the bug discussed in
            https://github.com/tensorflow/tensorflow/issues/37307, if `tf.einsum` is being used
            in ``tfbackend/ops.py`` rather than _einsum_v1.
        """
        if batch_size is not None:
            pytest.skip(
                "Cannot calculate gradient in batch mode, as tape.gradient "
                "cannot differentiate non-scalar output."
            )

        eng, prog = setup_eng(1)

        with prog.context as q:
            Sgate(prog.params("r"), prog.params("phi")) | q
            Dgate(prog.params("a")) | q

        a = tf.Variable(ALPHA)
        r = tf.Variable(0.105)
        phi = tf.Variable(0.123)

        with tf.GradientTape() as tape:
            state = eng.run(prog, args={"a": a, "r": r, "phi": phi}).state
            mean, _ = state.mean_photon(0)

        # test the mean and variance of the photon number is correct
        mean_ex = a ** 2 + tf.sinh(r) ** 2
        assert np.allclose(mean, mean_ex, atol=tol, rtol=0)

        # test the gradient of the mean is correct
        grad = tape.gradient(mean, [a, r, phi])
        grad_ex = [2 * a, 2 * tf.sinh(r) * tf.cosh(r), 0]
        assert np.allclose(grad, grad_ex, atol=tol, rtol=0) 

def displacedSqueezed(r_d, phi_d, r_s, phi_s, trunc):
    r"""
    The displaced squeezed state :math:`\ket{\alpha,\zeta} = D(\alpha)S(r\exp{(i\phi)})\ket{0}`  where `alpha = r_d * np.exp(1j * phi_d)` and `zeta = r_s * np.exp(1j * phi_s)`.
    """
    if np.allclose(r_s, 0.0):
        return coherentState(r_d, phi_d, trunc)

    if np.allclose(r_d, 0.0):
        return squeezedState(r_s, phi_s, trunc)

    ph = np.exp(1j * phi_s)
    ch = cosh(r_s)
    sh = sinh(r_s)
    th = tanh(r_s)
    alpha = r_d * np.exp(1j * phi_d)

    gamma = alpha * ch + np.conj(alpha) * ph * sh
    hermite_arg = gamma / np.sqrt(ph * np.sinh(2 * r_s) + 1e-10)

    # normalization constant
    N = np.exp(-0.5 * np.abs(alpha) ** 2 - 0.5 * np.conj(alpha) ** 2 * ph * th)

    coeff = np.array([(0.5 * ph * th) ** (n / 2) / np.sqrt(fac(n) * ch) for n in range(trunc)])
    vec = np.array([H(hermite_arg, row) for row in np.diag(coeff)])
    state = N * vec

    return state 

def squeezedState(r, theta, trunc):
    r"""
    The squeezed state :math:`S(re^{i\theta})`.
    """

    def entry(n):
        """squeezed summation term"""
        return (sqrt(fac(2 * n)) / (2 ** n * fac(n))) * (-exp(1j * theta) * tanh(r)) ** n

    vec = array([entry(n // 2) if n % 2 == 0 else 0.0 + 0.0j for n in range(trunc)])
    return sqrt(1 / cosh(r)) * vec 

def cir_int_rt_chf(u, t, k, theta, sigma, r0):
    r = np.sqrt(k ** 2 - 1j * u * 2 * sigma ** 2)
    cosh_fun = np.cosh(r * t / 2)
    sinh_fun = np.sinh(r * t / 2)
    coth_fun = cosh_fun / sinh_fun
    a_t_v = np.exp(t * theta * (k ** 2) / (sigma ** 2)) / (cosh_fun + (k / r) * sinh_fun) ** (
        2 * k * theta / (sigma ** 2))
    b_t_v = 2 * 1j * u / (k + r * coth_fun)
    return a_t_v * np.exp(b_t_v * r0) 

def transform(self, X):
        """Apply approximate feature map to X.

        Parameters
        ----------
        X : {array-like, sparse matrix}, shape = (n_samples, n_features)

        Returns
        -------
        X_new : {array, sparse matrix}, \
               shape = (n_samples, n_features * (2*sample_steps + 1))
            Whether the return value is an array of sparse matrix depends on
            the type of the input X.
        """
        msg = ("%(name)s is not fitted. Call fit to set the parameters before"
               " calling transform")
        check_is_fitted(self, "sample_interval_", msg=msg)

        X = check_array(X, accept_sparse='csr')
        sparse = sp.issparse(X)

        # check if X has negative values. Doesn't play well with np.log.
        if ((X.data if sparse else X) < 0).any():
            raise ValueError("Entries of X must be non-negative.")
        # zeroth component
        # 1/cosh = sech
        # cosh(0) = 1.0

        transf = self._transform_sparse if sparse else self._transform_dense
        return transf(X)