%Darren Pais
%fit to N degree polynomial for data
%outdata is the fitted result for 100 x values (change spacing to change this)
%indata is the input data matrix with pair-wise xy data in seperate rows
%vector a contains the polynomial coefficients

function [outdata]=fitNdeg(indata,N)



for j=N:-1:0
    Z(:,N-j+1)=indata(:,1).^j ;
end

V=inv(Z'*Z)*Z'*indata(:,2) ;

a=zeros(N,1) ;

for j=1:1:N+1
   a(j,1)=V(j,1);
end
%%%a=V(1,1); b=V(2,1); c=V(3,1);

spacing = 100 ;
outdata(:,1)=min(indata(:,1)):(max(indata(:,1))-min(indata(:,1)) )/spacing  :max(indata(:,1)) ;

dataout=0.*outdata(:,1) ;

for j=1:1:N+1 
    dataout=dataout+a(j,1).*outdata(:,1).^(N-j+1); 
end
outdata(:,2)=dataout ;
%%+ b.*outdata(:,1).^1 + c.*outdata(:,1).^0 ;