Python interpolate.splev方法代码示例

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def curve_length(self, start=None, end=None, precision=0.01):
        '''
        Calculates the length of the curve by dividing the curve up
        into pieces of parameterized-length <precision>.
        '''
        if start is None: start = self.t[0]
        if end is None: end = self.t[-1]
        from scipy import interpolate
        if self.order == 1:
            # we just want to add up along the steps...
            ii = [ii for (ii,t) in enumerate(self.t) if start < t and t < end]
            ts = np.concatenate([[start], self.t[ii], [end]])
            xy = np.vstack([[self(start)], self.coordinates[:,ii].T, [self(end)]])
            return np.sum(np.sqrt(np.sum((xy[1:] - xy[:-1])**2, axis=1)))
        else:
            t = np.linspace(start, end, int(np.ceil((end-start)/precision)))
            dt = t[1] - t[0]
            dx = interpolate.splev(t, self.splrep[0], der=1)
            dy = interpolate.splev(t, self.splrep[1], der=1)
            return np.sum(np.sqrt(dx**2 + dy**2)) * dt 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def residual(pars, spforcorr, sptarget=None):
        # unpack parameters:
        #  extract .value attribute for each parameter
        xs = pars['xshift'].value
        yx = pars['yshift'].value
        yx2 = pars['yshiftcarr'].value
        spcorr = np.zeros((shape(spforcorr)))
    
        # we need to resample the spectra to compare them
        tck = interpolate.splrep(spforcorr[:,0]-xs,spforcorr[:,1]*yx+spforcorr[:,1]**2*yx2,s=0)
        spcorr[:,0] = spforcorr[:,0]    
        spcorr[:,1] = interpolate.splev(spforcorr[:,0],tck,der=0)
        
        if sptarget is None: #in such case we return the corrected spectrum
            return spcorr
        return (spcorr[:,1] - sptarget[:,1])
    ###########################################################################        
        
    # Now we choose the portion of spectra to fit 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def residual(pars, spforcorr, sptarget=None):
            # unpack parameters:
            #  extract .value attribute for each parameter
            xs = pars['xshift'].value
            yx = pars['yshift'].value
            yx2 = pars['yshiftcarr'].value
            spcorr = np.zeros((shape(spforcorr)))
        
            # we need to resample the spectra to compare them
            tck = interpolate.splrep(spforcorr[:,0]-xs,spforcorr[:,1]*yx+spforcorr[:,1]**2*yx2,s=0)
            spcorr[:,0] = spforcorr[:,0]    
            spcorr[:,1] = interpolate.splev(spcorr[:,0],tck,der=0)
            
            if sptarget is None: #in such case we return the corrected spectrum
                return spcorr
            return (spcorr[:,1] - sptarget[:,1])
        #######################################################################        
        
        # Now we choose the portion of spectra to fit 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def get_velocities(positions, times, tol):
    positions = np.atleast_2d(positions)
    n = len(positions)
    deg = min(3, n - 1)

    good_inds = np.r_[True, (abs(times[1:] - times[:-1]) >= 1e-6)]
    good_positions = positions[good_inds]
    good_times = times[good_inds]

    if len(good_inds) == 1:
        return np.zeros(positions[0:1].shape)

    (tck, _) = si.splprep(good_positions.T, s=tol ** 2 * (n + 1), u=good_times, k=deg)
    # smooth_positions = np.r_[si.splev(times,tck,der=0)].T
    velocities = np.r_[si.splev(times, tck, der=1)].T
    return velocities 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def test_Taitel_Dukler_splines():
    from scipy.interpolate import splrep, splev
    import numpy as np
    from fluids.two_phase import Dukler_XA_tck, Dukler_XC_tck, Dukler_XD_tck
    Dukler_XA_tck2 = splrep(np.log10(Dukler_XA_Xs), np.log10(Dukler_XA_As), s=5e-3, k=3)
    [assert_close(i, j) for i, j in zip(Dukler_XA_tck, Dukler_XA_tck2)]
#     XA_interp = UnivariateSpline(np.log10(Dukler_XA_Xs), np.log10(Dukler_XA_As), s=5e-3, k=3) # , ext='const'
#    XA_interp_obj = lambda x: 10**float(splev(log10(x), Dukler_XA_tck))
    
    Dukler_XD_tck2 = splrep(np.log10(Dukler_XD_Xs), np.log10(Dukler_XD_Ds), s=1e-2, k=3)
    [assert_close(i, j) for i, j in zip(Dukler_XD_tck, Dukler_XD_tck)]
#     XD_interp = UnivariateSpline(np.log10(Dukler_XD_Xs), np.log10(Dukler_XD_Ds), s=1e-2, k=3) # , ext='const'
#    XD_interp_obj = lambda x: 10**float(splev(log10(x), Dukler_XD_tck))
    
    Dukler_XC_tck2 = splrep(np.log10(Dukler_XC_Xs), np.log10(Dukler_XC_Cs), s=1e-3, k=3)
    [assert_close(i, j) for i, j in zip(Dukler_XC_tck, Dukler_XC_tck2)]
#     XC_interp = UnivariateSpline(np.log10(Dukler_XC_Xs), np.log10(Dukler_XC_Cs), s=1e-3, k=3) # ext='const'
#    XC_interp_obj = lambda x: 10**float(splev(log10(x), Dukler_XC_tck))
    
    # Curves look great to 1E-4! Also to 1E4. 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def pla(data, period=15):
    N = int(len(data)/period)
    orig_x = range(0,len(data))
    tck = splrep(orig_x, data,s=0)
    test_xs = np.linspace(0,len(data),N)
    spline_ys = splev(test_xs, tck)
    spline_yps = splev(test_xs, tck, der=1)
    xi = np.unique(tck[0])
    yi = [[splev(x, tck, der=j) for j in xrange(3)] for x in xi]
    P = interpolate.PiecewisePolynomial(xi,yi,orders=1)
    test_ys = P(test_xs)
    #inter_y = interp0(test_xs, test_ys, orig_x)
    inter_y = interp1(test_xs, test_ys, orig_x)
    
    mae = sqrt(mean_absolute_error(inter_y, data))
    #       mae = np.var(inter_y-data)
    return mae

#def paa(data, period=15): 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def interpolate(x, x_arr, y_arr, type='interp', order=3, left=None,
                right=None):
    """Perform interpolation on value x using arrays x_arr
       and y_arr.  The type of interpolate is defined by interp

       type:
       interp--use numpy.interp
       spline--use scipy.splrep and splev

       return
    """
    if type == 'interp':
        y = np.interp(x, x_arr, y_arr, left=left, right=right)
    if type == 'spline':
        if left is None:
            y_arr[0] = left
        if right is None:
            y_arr[-1] = right

        tk = scint.splrep(x_arr, y_arr, k=order)
        y = scint.splev(x, tk, der=0)

    return y 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def interpolate(self, s_freq=4, interp_method='cubic'):
        rri = self.rri
        irregular_time = self.time
        step = 1 / float(s_freq)
        regular_time = arange(0, irregular_time[-1] + step, step)
        
        if interp_method == 'cubic':
            tck = splrep(irregular_time, rri, s=0)
            rri_interp = splev(regular_time, tck, der=0)
            
        elif interp_method == 'linear':
            rri_interp = interp(regular_time, irregular_time, rri)
            
        self.time_interp = regular_time
        self.rri_interp = rri_interp
        self.s_freq = s_freq 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def sample_613():
    """
    6.1.3 插值
    :return:
    """
    from scipy.interpolate import interp1d, splrep, splev

    # 示例两种插值计算方式
    _, axs = plt.subplots(nrows=1, ncols=2, figsize=(14, 5))

    # 线性插值
    linear_interp = interp1d(x, y)
    # axs[0]左边的
    axs[0].set_title('interp1d')
    # 在相同坐标系下，同样的x，插值的y值使r.绘制（红色点）
    axs[0].plot(x, y, '', x, linear_interp(x), 'r.')

    # B-spline插值
    splrep_interp = splrep(x, y)
    # axs[1]右边的
    axs[1].set_title('splrep')
    # #在相同坐标系下，同样的x，插值的y值使g.绘制（绿色点）
    axs[1].plot(x, y, '', x, splev(x, splrep_interp), 'g.')
    plt.show() 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def __call__(self, t, derivative=0):
        from scipy import interpolate
        xint = interpolate.splev(t, self.splrep[0], der=derivative, ext=0)
        yint = interpolate.splev(t, self.splrep[1], der=derivative, ext=0)
        return np.asarray([xint,yint]) 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def _evalfr(self, omega):
        """Evaluate a transfer function at a single angular frequency."""
        # Preallocate the output.
        if getattr(omega, '__iter__', False):
            out = empty((self.outputs, self.inputs, len(omega)), dtype=complex)
        else:
            out = empty((self.outputs, self.inputs), dtype=complex)

        if self.ifunc is None:
            try:
                out = self.fresp[:, :, where(self.omega == omega)[0][0]]
            except Exception:
                raise ValueError(
                    "Frequency %f not in frequency list, try an interpolating"
                    " FRD if you want additional points" % omega)
        else:
            if getattr(omega, '__iter__', False):
                for i in range(self.outputs):
                    for j in range(self.inputs):
                        for k, w in enumerate(omega):
                            frraw = splev(w, self.ifunc[i, j], der=0)
                            out[i, j, k] = frraw[0] + 1.0j * frraw[1]
            else:
                for i in range(self.outputs):
                    for j in range(self.inputs):
                        frraw = splev(omega, self.ifunc[i, j], der=0)
                        out[i, j] = frraw[0] + 1.0j * frraw[1]

        return out

    # Method for generating the frequency response of the system 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def _interpolate(xy, num_points):
  tck,u = splprep([
    xy[:,0],
    xy[:,1]],
    s=0
  )
  unew = linspace(0, 1, num_points)
  out = splev(unew, tck)
  return column_stack(out) 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def _rnd_interpolate(xy, num_points, ordered=False):
  tck,u = splprep([
    xy[:,0],
    xy[:,1]],
    s=0
  )
  unew = random(num_points)
  if ordered:
    unew = sort(unew)
  out = splev(unew, tck)
  return column_stack(out) 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def bspline(x, y, x_new):
    tck = interpolate.splrep(x, y, s=0)
    ynew = interpolate.splev(x_new, tck, der=0)
    return ynew 

# 需要导入模块: from scipy import interpolate [as 别名]
# 或者: from scipy.interpolate import splev [as 别名]
def field_map2field_func(z, By):
    tck = interpolate.splrep(z, By, k=3)
    func = lambda x, y, z: (0, interpolate.splev(z, tck, der=0), 0)
    return func