function F = set(varargin)
%SET Defines a constraint (the feasible set)
%
% F = SET([]) Creates an empty SET-object
% F = SET(X > Y) Constrains X-Y to be positive semi-definite if X-Y is Hermitian,
% interpreted as element-wise constraint otherwise
% F = SET(X==Y) Element-wise equality constraint
% F = SET(CONE(X,Y)) Second order cone constraint ||X|| %
% Constraints can also be generated using string notation (displays nicely with syntax high-lightning)
% F = SET('X>Y') Constrains X-Y to be positive semi-definite if X-Y is Hermitian,
% interpreted as element-wise constraint otherwise
% F = SET('X==Y') Element-wise equality constraint
% F = SET('||X|| % F = SET('cone(X,Y)') Create second order cone constraint (X and Y column vectors)
%
% Variables can be constrained to be integer or binary
% F = SET(INTEGER(X))
% F = SET(BINARY(X))
%
% Multiple constraints are obtained with overloaded plus
% F = SET(X > 0) + SET(CONE(X(:),1)) + SET(X(1,1) == 1/2)
%
% Double-sided constraint (and extensions) can easily be defined
% The following two comands give equivalent problems
% F = SET(X > 0 > Y > Z < 5 < W)
% F = SET(X > 0) + SET(0 > Y) + SET(Y > Z) + SET(Z < 5) + set(5 < W)
%
% A constraint can be tagged with a name or description
% F = SET(X > Y,'tag') Gives the constraint a description (used in display/checkset)
%
% General info
%
% The right-hand side and left-hand side can be interchanged. Supports {>,=, % See FAQ for information on strict vs. non-strict inequalities.
%
% Any valid expression built using DOUBLEs & SDPVARs can be used on both sides.
%
% The advantage of using the string notation approach is that more information will be
% shown when the SET is displayed (and in checkset)
%
% See also DUAL, SOLVESDP, INTEGER, BINARY
if isa(varargin{1},'blkvar')
varargin{1} = sdpvar(varargin{1});
end
switch nargin
case 0
F = lmi;
case 1
F = lmi(varargin{1});
case 2
F = lmi(varargin{1},varargin{2});
case 3
F = lmi(varargin{1},varargin{1},varargin{3});
otherwise
end
