pycubicspline.py 文件源码

def __init__(self, x, y):
        self.b, self.c, self.d, self.w = [], [], [], []

        self.x = x
        self.y = y

        self.nx = len(x)  # dimension of x
        h = np.diff(x)

        # calc coefficient c
        self.a = [iy for iy in y]

        # calc coefficient c
        A = self.__calc_A(h)
        B = self.__calc_B(h)
        self.c = np.linalg.solve(A, B)
        #  print(self.c1)

        # calc spline coefficient b and d
        for i in range(self.nx - 1):
            self.d.append((self.c[i + 1] - self.c[i]) / (3.0 * h[i]))
            tb = (self.a[i + 1] - self.a[i]) / h[i] - h[i] * \
                (self.c[i + 1] + 2.0 * self.c[i]) / 3.0
            self.b.append(tb)