AttributeError：模块'scipy.interpolate'没有属性'spline'

Question

我正在使用Python 3.6，并尝试运行以下来自here的代码：

from __future__ import division
import numpy as np
import matplotlib.pyplot as plt
import scipy.interpolate

x = np.array([ 2.,  1.,  1.,  2.,  2.,  4.,  4.,  3.])
y = np.array([ 1.,  2.,  3.,  4.,  2.,  3.,  2.,  1.])
plt.plot(x,y, label='poly')

t = np.arange(x.shape[0], dtype=float)
t /= t[-1]
nt = np.linspace(0, 1, 100)
x1 = scipy.interpolate.spline(t, x, nt)
y1 = scipy.interpolate.spline(t, y, nt)
plt.plot(x1, y1, label='range_spline')

t = np.zeros(x.shape)
t[1:] = np.sqrt((x[1:] - x[:-1])**2 + (y[1:] - y[:-1])**2)
t = np.cumsum(t)
t /= t[-1]
x2 = scipy.interpolate.spline(t, x, nt)
y2 = scipy.interpolate.spline(t, y, nt)
plt.plot(x2, y2, label='dist_spline')

plt.legend(loc='best')
plt.show()

但是它会产生错误，AttributeError: module 'scipy.interpolate' has no attribute 'spline'。

然后我通过从make_interp_spline导入scipy.interpolate来修改以下内容：

from __future__ import division
import numpy as np
import matplotlib.pyplot as plt
import scipy.interpolate
from scipy.interpolate import make_interp_spline

x = np.array([ 2.,  1.,  1.,  2.,  2.,  4.,  4.,  3.])
y = np.array([ 1.,  2.,  3.,  4.,  2.,  3.,  2.,  1.])
plt.plot(x,y, label='poly')

t = np.arange(x.shape[0], dtype=float)
t /= t[-1]
nt = np.linspace(0, 1, 100)
x1 = make_interp_spline(t, x, nt)
y1 = make_interp_spline(t, y, nt)
plt.plot(x1, y1, label='range_spline')

t = np.zeros(x.shape)
t[1:] = np.sqrt((x[1:] - x[:-1])**2 + (y[1:] - y[:-1])**2)
t = np.cumsum(t)
t /= t[-1]
x2 = make_interp_spline(t, x, nt)
y2 = make_interp_spline(t, y, nt)
plt.plot(x2, y2, label='dist_spline')

plt.legend(loc='best')
plt.show()

我收到新的错误ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()。

输出：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-9-2b54020d8fb1> in <module>
     12 t /= t[-1]
     13 nt = np.linspace(0, 1, 100)
---> 14 x1 = make_interp_spline(t, x, nt)
     15 y1 = make_interp_spline(t, y, nt)
     16 plt.plot(x1, y1, label='range_spline')

/usr/local/lib/python3.7/site-packages/scipy/interpolate/_bsplines.py in make_interp_spline(x, y, k, t, bc_type, axis, check_finite)
    751 
    752     # special-case k=0 right away
--> 753     if k == 0:
    754         if any(_ is not None for _ in (t, deriv_l, deriv_r)):
    755             raise ValueError("Too much info for k=0: t and bc_type can only "

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

只是想知道如何解决此问题？谢谢。

Answer 1

make_interp_spline的第三个参数是样条顺序（即三次样条为3，并且您使用数组nt调用它。