39 lines
1.3 KiB
Matlab
Executable File
39 lines
1.3 KiB
Matlab
Executable File
function varargout = SQRT(varargin)
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%SQRT (overloaded)
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%
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% t = sqrt(x)
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%
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% The variable t can only be used in concavity preserving
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% operations such as t>1, max t etc.
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%
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% When SQRT is used in a problem, the domain constraint
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% (x>=0) is automatically added to the problem.
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%
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% See also SDPVAR, SDPVAR/GEOMEAN
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switch class(varargin{1})
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case 'double' % What is the numerical value of this argument (needed for displays etc)
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X = sqrt(varargin{1});
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case 'sdpvar' % Overloaded operator for SDPVAR objects. Pass on args and save them.
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X = varargin{1};
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[n,m] = size(X);
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if is(varargin{1},'real') & (n*m==1)
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varargout{1} = yalmip('addextendedvariable',mfilename,varargin{:});
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else
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error('SQRT can only be applied to real scalars');
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end
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case 'char' % YALMIP send 'model' when it wants the epigraph or hypograph
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if isequal(varargin{1},'graph')
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t = varargin{2}; % Second arg is the extended operator variable
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X = varargin{3}; % Third arg and above are the args user used when defining t.
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varargout{1} = (cone([(X-1)/2;t],(X+1)/2));
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varargout{2} = struct('convexity','concave','monotonicity','increasing','definiteness','positive');
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varargout{3} = X;
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else
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end
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otherwise
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end
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