属性错误：模块'scipy.interpolate'没有属性'spline'

Question

我正在使用Python 3.6，并尝试运行以下代码，即

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()

但它会生成一个错误AttributeError: module 'scipy.interpolate' has no attribute 'spline'。

然后我通过从scipy.interpolate导入make_interp_spline修改为以下内容：

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()

我得到一个新的错误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这个问题？非常感谢。

Answer 1

make_interp_spline的第三个参数是样条函数的阶数(即三次样条函数为3(，您使用数组nt调用它。

如果要指定自己的结，请使用t=...命令。