[37] | 1 | function varargout = norm(varargin) |
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| 2 | %SIGN (overloaded) |
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| 3 | |
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| 4 | % Author Johan Löfberg |
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| 5 | % $Id: sign.m,v 1.1 2005/11/03 17:23:12 joloef Exp $ |
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| 6 | |
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| 7 | |
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| 8 | %% *************************************************** |
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| 9 | % This file defines a nonlinear operator for YALMIP |
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| 10 | % |
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| 11 | % It can take three different inputs |
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| 12 | % For DOUBLE inputs, it returns standard double values |
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| 13 | % For SDPVAR inputs, it generates an internal variable |
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| 14 | % |
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| 15 | % When first input is 'model' it returns the graph |
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| 16 | % in the first output and structure describing some |
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| 17 | % properties of the operator. |
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| 18 | |
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| 19 | %% *************************************************** |
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| 20 | switch class(varargin{1}) |
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| 21 | |
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| 22 | case 'double' % What is the numerical value of this argument (needed for displays etc) |
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| 23 | % SHOULD NEVER HAPPEN, THIS SHOULD BE CAUGHT BY BUILT-IN |
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| 24 | error('Overloaded SDPVAR/NORM CALLED WITH DOUBLE. Report error') |
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| 25 | |
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| 26 | case 'sdpvar' % Overloaded operator for SDPVAR objects. Pass on args and save them. |
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| 27 | if length(varargin{1}) == 1 |
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| 28 | varargout{1} = yalmip('addextendedvariable',mfilename,varargin{1}); |
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| 29 | else |
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| 30 | y = []; |
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| 31 | n = size(varargin{1},1); |
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| 32 | m = size(varargin{1},2); |
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| 33 | varargin{1} = reshape(varargin{1},n*m,1); |
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| 34 | for i = 1:prod(size(varargin{1})) |
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| 35 | inparg = extsubsref(varargin{1},i); |
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| 36 | if isa(inparg,'double') |
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| 37 | y = sign(inparg); |
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| 38 | else |
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| 39 | y = [y yalmip('addextendedvariable',mfilename,inparg)]; |
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| 40 | end |
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| 41 | end |
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| 42 | y = reshape(y,n,m); |
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| 43 | varargout{1} = y; |
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| 44 | end |
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| 45 | |
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| 46 | case 'char' % YALMIP sends 'model' when it wants the epigraph or hypograph |
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| 47 | switch varargin{1} |
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| 48 | case 'graph' |
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| 49 | t = varargin{2}; |
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| 50 | X = varargin{3}; |
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| 51 | |
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| 52 | % No linear model available |
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| 53 | |
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| 54 | varargout{1} = []; |
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| 55 | varargout{2} = []; |
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| 56 | varargout{3} = []; |
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| 57 | case 'milp' |
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| 58 | |
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| 59 | t = varargin{2}; |
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| 60 | X = varargin{3}; |
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| 61 | p = varargin{4}; |
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| 62 | |
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| 63 | d = binvar(1,1); |
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| 64 | [M,m] = derivebounds(X); |
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| 65 | F = set([]); |
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| 66 | F = set(X > d*m) + set(-2*d+1 <= t <= 1); |
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| 67 | F = set(X < (1-d)*M) + set(-1 <= t <= -1 + 2*(1-d)); |
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| 68 | |
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| 69 | varargout{1} = F; |
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| 70 | varargout{2} = struct('convexity','milp','monotonicity','milp','definiteness','positive'); |
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| 71 | varargout{3} = X; |
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| 72 | |
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| 73 | otherwise |
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| 74 | error('SDPVAR/NORM called with CHAR argument?'); |
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| 75 | end |
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| 76 | otherwise |
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| 77 | error('Strange type on first argument in SDPVAR/NORM'); |
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| 78 | end |
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