function W=ufdwt(h,pts,order)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% ufdwt.m
%
% Compute Finite Difference Weights for a Uniform Grid
%
% Input Parameters:
%
% h - spacing between FD nodes
% pts - number of FD points in scheme (3-pt, 5-pt, etc)
% order - order of the derivative operator to compute weights for
% (note: order<pts-1!)
% 1 computes first derivative differences
% 2 computes second derivative differences, etc
%
% Output Parameter:
%
% W is the weight matrix. Each row contains a different set of weights
% (centered or off). If, for example, the number of finite difference points
% is odd, the centered difference weights will appear in the middle row.
%
% Written by: Greg von Winckel - 06/16/04
% Contact: gregvw@chtm.unm.edu
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
N=2*pts-1; p1=pts-1;
A=repmat((0:p1)',1,N);
B=repmat((-p1:p1)*h,pts,1);
M=(B.^A)./gamma(A+1);
rhs=zeros(pts,1); rhs(order+1)=1;
W=zeros(pts,pts);
for k=1:pts
W(:,k)=M(:,(0:p1)+k)\rhs;
end
W=W'; W(1:pts,:)=W(pts:-1:1,:);
