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