Matlab之用牛顿均差求插值多项式

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! h& p* r! b, a1 f/ Z% 写出一个插值多项式
: M" L" `$ H8 H, r% input :vector(x,y),interpolation point x0
/ |7 K3 o! Y) B2 u) h' k% output:the result at x = x0
; z+ U4 I& Z& T9 Lfunction y0 = page_157_1(x ,y,x0)
format long
# ?9 S. P, F; m# }5 [9 ?5 Pn = length(x);
for j = 1:n     %fill in y colum of Newton triangle
  L% Z& S2 U7 k# C* y% z9 o- Z6 \2 |    v(j,1) = y(j);
  p/ e8 r5 B" O+ iend
for i = 2:n             %for colum i
    for j = 1:n+1-i             %fill in colum from top to bottom
: ^' Q, ]: i' ]2 D9 u4 v1 M        v(j,i) = (v(j+1,i-1) - v(j,i-1))/(x(j+i-1)-x(j));
    end
4 N% n: B' w; yend
for i = 1:n
% T" L& c( S4 F! C+ [4 Z- X    v(i) = v(1,i);     %read along top of triangle      
end     %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
* u/ O* }  Z# t* \+ R0 Y; J4 F

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Matlab之用牛顿均差求插值多项式