51 lines
1.5 KiB
Mathematica
51 lines
1.5 KiB
Mathematica
|
%%***********************************************************************
|
||
|
|
%% skron: Find the matrix presentation of
|
||
|
|
%% symmetric kronecker product skron(A,B), where
|
||
|
|
%% A,B are symmetric.
|
||
|
|
%%
|
||
|
|
%% Important: A,B are assumed to be symmetric.
|
||
|
|
%%
|
||
|
|
%% K = skron(blk,A,B);
|
||
|
|
%%
|
||
|
|
%% blk: a cell array specifying the block diagonal structure of A,B.
|
||
|
|
%%
|
||
|
|
%% (ij)-column of K = 0.5*svec(AUB + BUA), where
|
||
|
|
%% U = xij*(ei*ej' + ej*ei')
|
||
|
|
%% xij = 1/2 if i=j
|
||
|
|
%% = 1/sqrt(2) otherwise.
|
||
|
|
%%*****************************************************************
|
||
|
|
%% SDPT3: version 4.0
|
||
|
|
%% Copyright (c) 1997 by
|
||
|
|
%% Kim-Chuan Toh, Michael J. Todd, Reha H. Tutuncu
|
||
|
|
%% Last Modified: 16 Sep 2004
|
||
|
|
%%*****************************************************************
|
||
|
|
|
||
|
|
function K = skron(blk,A,B);
|
||
|
|
|
||
|
|
if iscell(A) & ~ iscell(B)
|
||
|
|
error('skron: A,B must be both matrices or both cell arrays')
|
||
|
|
end
|
||
|
|
if iscell(A)
|
||
|
|
K = cell(size(blk,1),1);
|
||
|
|
for p = 1:size(blk,1)
|
||
|
|
if (norm(A{p}-B{p},'fro') < 1e-13)
|
||
|
|
sym = 1;
|
||
|
|
else
|
||
|
|
sym = 0;
|
||
|
|
end
|
||
|
|
if strcmp(blk{p,1},'s')
|
||
|
|
K{p} = mexskron(blk(p,:),A{p},B{p},sym);
|
||
|
|
end
|
||
|
|
end
|
||
|
|
else
|
||
|
|
if (norm(A-B,'fro') < 1e-13)
|
||
|
|
sym = 1;
|
||
|
|
else
|
||
|
|
sym = 0;
|
||
|
|
end
|
||
|
|
if strcmp(blk{1,1},'s')
|
||
|
|
K = mexskron(blk,A,B,sym);
|
||
|
|
end
|
||
|
|
end
|
||
|
|
%%***********************************************************************
|