Python scipy.special.i1() Examples

The following are 15 code examples of scipy.special.i1(). You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may also want to check out all available functions/classes of the module scipy.special , or try the search function .
Example #1
Source File: vonmises.py    From cgpm with Apache License 2.0 6 votes vote down vote up 
def estimate_kappa(N, ssx, scx):
        if N == 0:
            return 10.**-6
        elif N == 1:
            return 10*pi
        else:
            rbar2 = (ssx / N) ** 2. + (scx / N) ** 2.
            rbar = rbar2 ** .5
            kappa = rbar*(2. - rbar2) / (1. - rbar2)

        A_p = lambda k : bessel_1(k) / bessel_0(k)

        Apk = A_p(kappa)
        kappa_1 = kappa - (Apk - rbar)/(1. - Apk**2 - (1. / kappa) * Apk)
        Apk = A_p(kappa_1)
        kappa = kappa_1 - (Apk - rbar)/(1. - Apk**2 - (1. / kappa_1) * Apk)
        Apk = A_p(kappa)
        kappa_1 = kappa - (Apk - rbar)/(1. - Apk**2 - (1. / kappa) * Apk)
        Apk = A_p(kappa_1)
        kappa = kappa_1 - (Apk - rbar)/(1. - Apk**2 - (1. / kappa_1) * Apk)

        if isnan(kappa):
            return 10.**-6
        else:
            return abs(kappa)
Example #2
Source File: gain.py    From DeepXi with Mozilla Public License 2.0 6 votes vote down vote up 
def mmse_stsa(xi, gamma):
	"""
	Computes the MMSE-STSA gain function.

	Argument/s:
		xi - a priori SNR.
		gamma - a posteriori SNR.

	Returns:
		G - MMSE-STSA gain function.
	"""
	nu = np.multiply(xi, np.divide(gamma, np.add(1, xi)))
	G = np.multiply(np.multiply(np.multiply(np.divide(np.sqrt(np.pi), 2),
		np.divide(np.sqrt(nu), gamma)), np.exp(np.divide(-nu,2))),
		np.add(np.multiply(np.add(1, nu), i0(np.divide(nu,2))),
		np.multiply(nu, i1(np.divide(nu, 2))))) # MMSE-STSA gain function.
	idx = np.isnan(G) | np.isinf(G) # replace by Wiener gain.
	G[idx] = np.divide(xi[idx], np.add(1, xi[idx])) # Wiener gain.
	return G
Example #3
Source File: _continuous_distns.py    From lambda-packs with MIT License 5 votes vote down vote up 
def _entropy(self, kappa):
        return (-kappa * sc.i1(kappa) / sc.i0(kappa) +
                np.log(2 * np.pi * sc.i0(kappa)))
Example #4
Source File: test_basic.py    From Computable with MIT License 5 votes vote down vote up 
def test_i1(self):
        assert_equal(cephes.i1(0),0.0)
Example #5
Source File: test_basic.py    From Computable with MIT License 5 votes vote down vote up 
def test_i1_series(self):
        for z in [1., 10., 200.5]:
            value, err = self.iv_series(1, z)
            assert_tol_equal(special.i1(z), value, atol=err, err_msg=z)
Example #6
Source File: test_basic.py    From Computable with MIT License 5 votes vote down vote up 
def test_i1(self):
        values = [[0.0, 0.0],
                  [1e-10, 0.4999999999500000e-10],
                  [0.1, 0.0452984468],
                  [0.5, 0.1564208032],
                  [1.0, 0.2079104154],
                  [5.0, 0.1639722669],
                  [20.0, 0.0875062222],
                  ]
        for i, (x, v) in enumerate(values):
            cv = special.i1(x) * exp(-x)
            assert_almost_equal(cv, v, 8, err_msg='test #%d' % i)
Example #7
Source File: _continuous_distns.py    From GraphicDesignPatternByPython with MIT License 5 votes vote down vote up 
def _entropy(self, kappa):
        return (-kappa * sc.i1(kappa) / sc.i0(kappa) +
                np.log(2 * np.pi * sc.i0(kappa)))
Example #8
Source File: test_basic.py    From GraphicDesignPatternByPython with MIT License 5 votes vote down vote up 
def test_i1(self):
        assert_equal(cephes.i1(0),0.0)
Example #9
Source File: test_basic.py    From GraphicDesignPatternByPython with MIT License 5 votes vote down vote up 
def test_i1_series(self):
        for z in [1., 10., 200.5]:
            value, err = self.iv_series(1, z)
            assert_allclose(special.i1(z), value, atol=err, err_msg=z)
Example #10
Source File: test_basic.py    From GraphicDesignPatternByPython with MIT License 5 votes vote down vote up 
def test_i1(self):
        values = [[0.0, 0.0],
                  [1e-10, 0.4999999999500000e-10],
                  [0.1, 0.0452984468],
                  [0.5, 0.1564208032],
                  [1.0, 0.2079104154],
                  [5.0, 0.1639722669],
                  [20.0, 0.0875062222],
                  ]
        for i, (x, v) in enumerate(values):
            cv = special.i1(x) * exp(-x)
            assert_almost_equal(cv, v, 8, err_msg='test #%d' % i)
Example #11
Source File: __init__.py    From fluids with MIT License 5 votes vote down vote up 
def cy_bispev(tx, ty, c, kx, ky, x, y):
    '''Possible optimization: Do not evaluate derivatives, ever.
    '''
    nx = len(tx)
    ny = len(ty)
    mx = len(x)
    my = len(y)

    kx1 = kx + 1
    ky1 = ky + 1

    nkx1 = nx - kx1
    nky1 = ny - ky1
    
    wx = [[0.0]*kx1]*mx
    wy = [[0.0]*ky1]*my
    lx = [0]*mx
    ly = [0]*my

    size_z = mx*my
    
    z = [0.0]*size_z
    init_w(tx, kx, x, lx, wx)
    init_w(ty, ky, y, ly, wy)
    
    for j in range(my):
        for i in range(mx):
            sp = 0.0
            err = 0.0
            for i1 in range(kx1):
                for j1 in range(ky1):
                    l2 = lx[i]*nky1 + ly[j] + i1*nky1 + j1
                    a = c[l2]*wx[i][i1]*wy[j][j1] - err
                    tmp = sp + a
                    err = (tmp - sp) - a
                    sp = tmp
            z[j*mx + i] += sp
    return z
Example #12
Source File: __init__.py    From fluids with MIT License 5 votes vote down vote up 
def i1(*args, **kwargs):
        from scipy.special import i1
        return i1(*args, **kwargs)
Example #13
Source File: __init__.py    From fluids with MIT License 5 votes vote down vote up 
def erf(*args, **kwargs):
            from scipy.special import erf
            return erf(*args, **kwargs)


#    from scipy.special import lambertw, ellipe, gammaincc, gamma # fluids
#    from scipy.special import i1, i0, k1, k0, iv # ht
#    from scipy.special import hyp2f1    
#    if erf is None:
#        from scipy.special import erf
Example #14
Source File: __init__.py    From fluids with MIT License 5 votes vote down vote up 
def i1(x):
        import mpmath
        return mpmath.mpmath.besseli(1, x)
Example #15
Source File: _continuous_distns.py    From Splunking-Crime with GNU Affero General Public License v3.0 5 votes vote down vote up 
def _entropy(self, kappa):
        return (-kappa * sc.i1(kappa) / sc.i0(kappa) +
                np.log(2 * np.pi * sc.i0(kappa)))