function y = add3(x1,x2,x3)
%ADD3 Node. Ternary addition function.
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%   Y = ADD3(X1,X2,X3) returns as Y the result of X1 + X2 + X3
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%   Copyright (c) 2009-2015 Dominic Searson 
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%   GPTIPS 2
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%   See also MULT3

y=x1 + x2 + x3;