1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
|
%%*******************************************************************
%% Convert a square symmetric matrix to a vector
%% representation used by DSDP
%%
%% [V] = dvec(A)
%%
%% Input: A = square symmetric matrix. Lower triangular entries
%% are ignored.
%%
%% Output: V = column vector representing half of a symmetric matrix.
%% If A has n rows and columns, V is a column vector with
%% n*(n+1)/2 rows.
%%
%% See also: DSPARSE, DMAT (its inverse operator)
%%
%% DSDP5.0
%% Copyright (c) 2003 by
%% S. Benson and Y. Ye
%% Last modified: December 2003
%%******************************************************************
function [V]=dvec(A);
[n,n1]=size(A);
if (n~=n1) error('Matrix not square.'); end;
nn=n*(n+1)/2;
V=zeros(nn,1);
for i=1:n,
k1=i*(i-1)/2+1; k2=i*(i+1)/2;
V(k1:k2,1) = A(1:i,i);
end;
V=sparse(V);
|
