33 lines
816 B
Matlab
Executable File
33 lines
816 B
Matlab
Executable File
function varargout = xexpintinv(varargin)
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%XEXPINTINV EXPINT(1/Z)/Z
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switch class(varargin{1})
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case 'double'
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z = varargin{1};
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varargout{1} = (1./z).*expint(1./z);
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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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varargout{1} = [];
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varargout{2} = createOperator;
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varargout{3} = varargin{3};
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otherwise
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error('SDPVAR/EXPINT called with CHAR argument?');
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end
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function operator = createOperator
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operator = struct('convexity','none','monotonicity','none','definiteness','positive','model','callback');
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operator.derivative = @derivative;
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operator.range = [0 1];
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operator.domain = [1e-8 inf];
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function d = derivative(z);
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d = (-1./z.^2).*expint(1./z)+(1./z).*(-z.*exp(-1./z)).*(-1./z.^2);
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