1 | function Y=trace(X) |
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2 | %TRACE (overloaded) |
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3 | |
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4 | % Author Johan Löfberg |
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5 | % $Id: trace.m,v 1.6 2006/07/26 20:17:58 joloef Exp $ |
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6 | |
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7 | if isa(X,'blkvar') |
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8 | X = sdpvar(X); |
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9 | end |
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10 | |
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11 | if X.typeflag~=0 |
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12 | error('Relational objects cannot be manipulated') |
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13 | end |
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14 | |
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15 | Y = X; |
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16 | x_lmi_variables = X.lmi_variables; |
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17 | lmi_variables = []; |
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18 | n = X.dim(1); |
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19 | m = X.dim(2); |
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20 | |
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21 | if n == m % Standard case fast |
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22 | ind = 1:(n+1):n^2; |
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23 | Y.basis = sum(X.basis(ind,:),1); |
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24 | ind = find(Y.basis(2:end)); |
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25 | if isempty(ind) |
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26 | Y = full(Y.basis(1)); |
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27 | else |
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28 | Y.basis = Y.basis([1 1+ind]); |
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29 | Y.lmi_variables = X.lmi_variables(ind); |
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30 | Y.dim(1) = 1; |
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31 | Y.dim(2) = 1; |
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32 | end |
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33 | else |
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34 | traceX = trace(reshape(X.basis(:,1),n,m)); |
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35 | Y.basis = traceX(:); |
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36 | |
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37 | j = 1; |
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38 | for i = 1:length(x_lmi_variables) |
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39 | traceX = trace(reshape(X.basis(:,i+1),n,m))/1; |
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40 | if (norm(traceX,inf)>0) |
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41 | Y.basis(:,j+1) = traceX(:); |
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42 | lmi_variables = [lmi_variables x_lmi_variables(i)]; |
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43 | j = j+1; |
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44 | end |
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45 | end |
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46 | if isempty(lmi_variables) |
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47 | Y = full(trace(reshape(X.basis(:,1),n,m))); |
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48 | else |
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49 | Y.dim(1) = size(traceX,1); |
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50 | Y.dim(2) = size(traceX,2); |
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51 | Y.lmi_variables = lmi_variables; |
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52 | % Reset info about conic terms |
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53 | Y.conicinfo = [0 0]; |
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54 | end |
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55 | end |
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