sublinearinterp.py

实现Lagrange,Hermite,以及分段线性插值算法,需要用from * import *引用,如要使用lagrange, from lagrange import lagrange

#C:\Python24\
#Filename: sublinearinterp.py
from numpy import *
def sublinearinterp(x,y,xi):
    n=len(x)
    m=len(xi)
    yi=zeros(m,float)
    for i in range(0,m):
        xt=xi[i]
        for k in range(0,n):
            if x[k]>xt:
                break
        vx=x[k]
        vy=y[k]
        ux=x[k-1]
        uy=y[k-1]
        yi[i]=uy*(vx-xt)/(vx-ux)+vy*(xt-ux)/(vx-ux)
    return yi
if __name__ == '__main__':
    x=arange(0,10.1,.1)
    y=sin(x);
    xi=arange(0,10.1,.25)
    yi=sublinearinterp(x,y,xi)
    print yi