37 lines
881 B
Mathematica
37 lines
881 B
Mathematica
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function varargout = asec(varargin)
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%ASEC (overloaded)
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switch class(varargin{1})
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case 'sdpvar'
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varargout{1} = InstantiateElementWise(mfilename,varargin{:});
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case 'char'
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operator = struct('convexity','none','monotonicity','none','definiteness','none','model','callback');
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operator.convexhull = [];
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operator.bounds = @bounds;
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operator.derivative = @(x)(1./(x.*(x.^2-1).^0.5));
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varargout{1} = [varargin{3}.^2 >= 1]; % Disconnected domain
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varargout{2} = operator;
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varargout{3} = varargin{3};
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otherwise
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error('SDPVAR/ASEC called with CHAR argument?');
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end
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function [L,U] = bounds(xL,xU)
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if xU <= -1 || xL >= 1
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L = asec(xL);
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U = asec(xU);
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elseif xL < 0 & xU > 0
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L = 0;
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U = pi;
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elseif xU < 0 || xL > 0
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L = real(asec(xL));
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U = real(asec(xU));
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else
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L = 0;
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U = pi;
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end
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