can anyone explain me how to use this program
function y=lagrange(x,pointx,pointy)%
%LAGRANGE approx a point-defined function using the Lagrange polynomial interpolation
%% LAGRANGE(X,POINTX,POINTY) approx the function definited by the points:
% P1=(POINTX(1),POINTY(1)), P2=(POINTX(2),POINTY(2)), ..., PN(POINTX(N),POINTY(N))
% and calculate it in each elements of X
%% If POINTX and POINTY have different number of elements the function will return the NaN value
%% function wrote by: Calzino
% 7-oct-2001
%n=size(pointx,2);L=ones(n,size(x,2));if (size(pointx,2)~=size(pointy,2)) fprintf(1,'\nERROR!\nPOINTX and POINTY must have the same number of elements\n'); y=NaN;else for i=1:n for j=1:n if (i~=j) L(i,:)=L(i,:).*(x-pointx(j))/(pointx(i)-pointx(j)); end end end y=0; for i=1:n y=y+pointy(i)*L(i,:); endend
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