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upwind_WENO.m in LevelSetMethods.rar

			
function [data_x] = upwind_WENO(data, F, dx)
%
% Calculates the upwind derivative using
% fifth order accurate WENO scheme
% takes 1-D data
% data: input data
% F: force field
% dx: grid resolution
% Note: before entering this function, data and F need to be 
% extended by 3 at the beginning and end (values don't matter)
%
% Author: Baris Sumengen  sumengen@ece.ucsb.edu
% http://vision.ece.ucsb.edu/~sumengen/
%


if length(F) == 1
    F = F*ones(size(data));
end

if length(data) ~= length(F)
    error('force and data lengths does not match');
end

data_x = zeros(size(data));

% extrapolate the beginning and end points of data
data(3) = 2*data(4)-data(5);
data(2) = 2*data(3)-data(4);
data(1) = 2*data(2)-data(3);
data(end-2) = 2*data(end-3)-data(end-4);
data(end-1) = 2*data(end-2)-data(end-3);
data(end) = 2*data(end-1)-data(end-2);

D1 = (data(2:end)-data(1:end-1))/dx;

for i=1:(length(data)-6)
    if F(i+3) > 0  % use D-
        k = i-1;
        v1 = D1(k+1);
 			

			...
			...
			... to be continued.

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