numpy.interp
作用：给定1维数据点上做插入。
Parameters: x : 要估计坐标点的x坐标值。
xp : x坐标值，must be increasing if argument period is not specified. Otherwise, xp is internally sorted after normalizing the periodic boundaries with xp = xp % period.
fp : y坐标值, same length as xp.
right : 对应x > xp[-1]时fp的default is fp[-1].
period : x坐标轴的周期，声明忽略左边或者右边的插值。
return： y :The interpolated values, same shape as x.
例子：
x = np.linspace(0, 2*np.pi, 10)
y = np.sin(x)
xvals = np.linspace(0, 2*np.pi, 50)
yinterp = np.interp(xvals, x, y)
import matplotlib.pyplot as plt
plt.plot(x, y, 'o')
plt.plot(xvals, yinterp, '-x')
plt.show()
