42 lines
1.4 KiB
Mathematica
42 lines
1.4 KiB
Mathematica
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function varargout = nnz(varargin)
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%NNZ (overloaded)
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%
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% n = nnz(X)
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%
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% The NNZ operator is implemented using the concept of nonlinear operators
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% in YALMIP. NNZ(X) creates a new so called derived variable that can be
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% treated as any other variable in YALMIP. When OPTIMIZE is issued,
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% logic constraints are added to the problem to model the NNZ operator.
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switch class(varargin{1})
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case 'sdpvar'
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% Simple binary vector?
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if all(ismember(getvariables(varargin{1}),yalmip('binvariables')))
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if is(varargin{1},'lpcone')
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varargout{1} = sum(reshape(varargin{1},prod(size(varargin{1})),1));
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return
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end
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end
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% Nope, more advanced variable.
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varargout{1} = yalmip('define','nnz',varargin{:});
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case 'char'
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z = varargin{2};
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x = varargin{3};
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switch varargin{1}
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case 'graph'
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F = nnz_internal(z,x,0);
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properties = struct('convexity','convex','monotonicity','none','definiteness','none','model','graph');
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case {'exact','integer'}
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F = nnz_internal(z,x,1);
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properties = struct('convexity','none','monotonicity','none','definiteness','none','model','integer');
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otherwise
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error('Unexpected call to NNZ OPERATOR')
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end
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varargout{1} = F;
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varargout{2} = properties ;
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varargout{3} = x;
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otherwise
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end
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