function tbl = DividDif(x,y)
% usage: DividDif(x,y)
% description: for input vectors x of abscissas and y of ordinates
% of function f(x), returns a zero padded matrix whose ith row
% is the ith diagonal of a divided difference table for the data.

n = length(y);
if (n ~= length(x))
  disp('There is a size mismatch in abscissas and ordinates');
  return;
end;
x = x(:); % make x,y columns
y = y(:);
tbl = zeros(n,n+1);
tbl(:,1) = x(:);
tbl(:,2) = y(:);
for k = (3:n+1)
  tbl(1:n-k+2,k) = (tbl(2:n-k+3,k-1)-tbl(1:n-k+2,k-1))./(x(k-1:n)-x(1:n-k+2));
end;


