14

我编写了以下代码来执行样条插值:

import numpy as np
import scipy as sp

x1 = [1., 0.88,  0.67,  0.50,  0.35,  0.27, 0.18,  0.11,  0.08,  0.04,  0.04,  0.02]
y1 = [0., 13.99, 27.99, 41.98, 55.98, 69.97, 83.97, 97.97, 111.96, 125.96, 139.95, 153.95]

x = np.array(x1)
y = np.array(y1)

new_length = 25
new_x = np.linspace(x.min(), x.max(), new_length)
new_y = sp.interpolate.interp1d(x, y, kind='cubic')(new_x)

但我得到:

ValueError: A value in x_new is below the interpolation range.

interpolate.py

任何帮助,将不胜感激。

4

3 回答 3

18

scipy.interpolate.interp1d 上的 scipy 文档

scipy.interpolate.interp1d(x, y, kind='linear', axis=-1, copy=True, bounds_error=True, fill_value=np.nan)

x:array_like。单调递增实数值的一维数组。

...

问题是 x 值不是单调递增的。事实上,它们是单调递减的。让我知道这是否有效,以及它是否仍然是您正在寻找的计算。:

import numpy as np
import scipy as sp
from scipy.interpolate import interp1d

x1 = sorted([1., 0.88, 0.67, 0.50, 0.35, 0.27, 0.18, 0.11, 0.08, 0.04, 0.04, 0.02])
y1 = [0., 13.99, 27.99, 41.98, 55.98, 69.97, 83.97, 97.97, 111.96, 125.96, 139.95, 153.95]

new_length = 25
new_x = np.linspace(x.min(), x.max(), new_length)
new_y = sp.interpolate.interp1d(x, y, kind='cubic')(new_x)
于 2012-08-07T18:47:51.833 回答
14

您可以通过以下方式获得此信息:

import numpy as np
import scipy as sp
from scipy.interpolate import interp1d

x1 = [1., 0.88,  0.67,  0.50,  0.35,  0.27, 0.18,  0.11,  0.08,  0.04,  0.04,  0.02]
y1 = [0., 13.99, 27.99, 41.98, 55.98, 69.97, 83.97, 97.97, 111.96, 125.96, 139.95, 153.95]

# Combine lists into list of tuples
points = zip(x1, y1)

# Sort list of tuples by x-value
points = sorted(points, key=lambda point: point[0])

# Split list of tuples into two list of x values any y values
x1, y1 = zip(*points)

new_length = 25
new_x = np.linspace(min(x1), max(x1), new_length)
new_y = sp.interpolate.interp1d(x1, y1, kind='cubic')(new_x)
于 2014-06-09T15:18:11.850 回答
0

我刚刚收到上述错误并通过删除 X 和 Y 数组中的重复值来修复它。

x = np.sort(np.array([0, .2, .2, .4, .6, .9]))
y = np.sort(np.sort(np.array([0, .1, .06, .11, .25, .55]))

⬇将0.2更改为0.3或任何数字。

x = np.sort(np.array([0, .2, .3, .4, .6, .9]))
y = np.sort(np.sort(np.array([0, .1, .06, .11, .25, .55]))
于 2020-10-31T20:46:08.163 回答