%
%  my first matlab function
%
%  save as: "wpoly.m"
%
%  to run:  type "wpoly(x,N,a)" at the matlab prompt, 
%  where x,N,a are pre-defined, or just "wpoly(pi,2,0)"
%
%  try "help function"
%
%  it also works for vector-valued x!
%
%- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

function [out] = wpoly(x,N,a)

y = ones(size(x));  N = floor(abs(N));
            
for j = 1:N
  y = y.*(x-j);
end

out = y - a*N*(N+1)/2*x.^(N-1);

%
%  !!! NOTE:  you can use this within wilk.m !!!
%