Matlab之用牛顿均差求插值多项式

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% page 151  3
/ _3 C, V  p( f# \  ?' H% 写出一个插值多项式
% input :vector(x,y),interpolation point x0
% M+ l, ~. o, e: T) m9 c3 j% output:the result at x = x0
function y0 = page_157_1(x ,y,x0)
format long
n = length(x);
for j = 1:n     %fill in y colum of Newton triangle
    v(j,1) = y(j);
, p& W; }4 T0 ?( l! a; }1 pend
for i = 2:n             %for colum i
# R; C% X, x( H; a3 U( D$ W    for j = 1:n+1-i             %fill in colum from top to bottom
        v(j,i) = (v(j+1,i-1) - v(j,i-1))/(x(j+i-1)-x(j));
    end
end
for i = 1:n
6 q4 t7 n3 `5 {& ?- t8 I    v(i) = v(1,i);     %read along top of triangle      
( `! }* T+ n* o# K# F: Qend     %output coefficients
y0 = v(n)*(x0 - x(n-1)) + v(n-1);  %initial nest
for i = 1:n-2                          %use nest
    y0 = y0*(x0 - x(n-1-i)) + v(n-1-i);
end
) G% `/ ^1 L* P4 q

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Matlab之用牛顿均差求插值多项式