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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