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lap = laplacian(y, x, order, wrap);
lap = laplacian(y, x, order, wrap); y is a vector containing the y-coordinate (column) values. If the Laplacian for a uniform grid is desired, just input y and x as ones (or appropriately scaled) vectors. x follows the same convention as y, except refers to the x-coordinate (row) values. order is not yet supported. I'll try and figure a way so that order refers to the order of accuracy for the second derivatives in the Laplacian.
function lap = laplacian(y, x, order, wrap); if nargin == 2; order = 2; wrap = ['f']; end; if nargin == 3; if issrt(order); wrap = order; order = 2; else; wrap = ['f']; end if rem(order, 2) ~= 0; error('order must be an even number'); end; [m,n] = size(y); if (m ~= 1 | n ~= 1); error('y must be a vector'); end [m,n] = size(x); if (m ~= 1 | n ~= 1); error('x must be a vector'); end [m, n] = [length(y), length(x)]; % Determine coefficients for 'order'th order finite difference % equation for the second derivative. n = order; % For simplicity of writing lin_eq = zeros(n+1); for i = 1:(n+1); for j = 1:(n+1); lin_eq(i,j) = (i-(n/2)).^(i-1) /