%RTM_LENS Generate a ray transfer matrix for a paraxial lens.
%  RTM_LENS(F) returns a 2x2 ray transfer matrix for a paraxial lens of
%  focal length F.
%
%See also: RTM_DISTANCE

% $Author: graceej $ $Date: 2009/10/24 11:08:05 $
% $Revision: 1.4 $


% Copyright (c) 2009, Edward J. Grace
% All rights reserved.
 
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% without modification, are permitted provided that the following 
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%       provided with the distribution.
%     * Neither the name of the Imperial College London nor the 
%       names of its contributors may be used to endorse or 
%       promote products derived  this software without specific 
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function m=rtm_lens(f)
m=[1 0; -1/f 1];