Matlab之用牛顿均差求插值多项式

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% page 151  3
% 写出一个插值多项式
% input :vector(x,y),interpolation point x0
% output:the result at x = x0
( `1 P+ w% ?( @2 P' r( nfunction y0 = page_157_1(x ,y,x0)
format long
n = length(x);
* g0 O; G3 c% l- J! ?2 r0 U5 j0 {7 O1 x) tfor j = 1:n     %fill in y colum of Newton triangle
0 Y; I' z. q5 c" r1 k) T% |    v(j,1) = y(j);
end
for i = 2:n             %for colum i
, X9 B3 I; D6 d    for j = 1:n+1-i             %fill in colum from top to bottom
5 _( P$ a. Y& K  ^  ]        v(j,i) = (v(j+1,i-1) - v(j,i-1))/(x(j+i-1)-x(j));
    end
end
for i = 1:n
    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
" A( L0 {1 Y* w9 dfor i = 1:n-2                          %use nest
+ R8 P5 p, S6 ~( z1 {  X    y0 = y0*(x0 - x(n-1-i)) + v(n-1-i);
end

youOK

Matlab之用牛顿均差求插值多项式