scipy.interpolate.splrep为b样条提供了不正确的插值

Question

我使用以下代码：

x = [80, 85, 90, 95, 100, 105, 110, 115]
y = [0.31976258043267208, 0.31718670335264199, 0.30116311412953689, 0.29687766899837931, 0.29802720516866577, 0.30707962224836099, 0.32328422706655086, 0.34467623793716823]
bSpline = scipy.interpolate.splrep(x, y, k=3)
yInterp = scipy.interpolate.splev(np.linspace(0,1,num=8), bSpline)

但是bSpline有一些奇怪的结（有些是0），然后yEnterprise就一团糟：

 bSpline: (array([  80,   80,   80,   80,   90,   95,  100,  105,  115, 115,  115,  115 ]), array([ 0.31976258,  0.33015199,  0.29797999,  0.29680536,  0.29635823,
    0.30911387,  0.32907255,  0.34467624,  0,  0, 0,  0 ]), 3)
 yInterp: [-29.46356522 -29.3160613  -29.16904367 -29.02251153 -28.87646408, -28.73090053 -28.58582008 -28.44122191]

yEnterprise的某些值应该在正0.30左右，而不是-28和-29

Answer 1

传递给splrep的x值范围为80到115。您正在以0到1之间的值评估样条曲线。如果在输入范围内的值进行评估，输出将在0.3左右。