Dynamic-Calibration/utils/SDPT3-4.0/Examples/randsdp.m

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Matlab
Executable File

%%*******************************************************************
%% randsdp.m : creates random feasible SDP problems with various block
%% diagonal structures.
%%
%% [blk,Avec,C,b,X0,y0,Z0] = randsdp(dense_blk,sparse_blk,diag_blk,m,feas,solve);
%%
%% E.g.
%% randsdp([32 20],[10 5],100,10,feas,solve);
%%
%% dense_blk : for generating dense blocks, where
%% dense_blk(i) is the dimension of the ith block
%% sparse_blk: for generating a sparse block of small subblocks, where
%% sparse_blk(i) is the size of the ith subblock.
%% diag_blk : for generating a column vector of length specified by
%% diag_blk (this corresponds to a diagonal block).
%%
%% feas = 2 if want centered feasible starting point
%% = 1 if want feasible starting point
%% = 0 if otherwise. (default)
%%
%% solve = 0 just to initialize (default)
%% = 1 if want to solve the problem.
%%*****************************************************************
%% SDPT3: version 4.0
%% Copyright (c) 1997 by
%% Kim-Chuan Toh, Michael J. Todd, Reha H. Tutuncu
%% Last Modified: 16 Sep 2004
%%*****************************************************************
function [blk,Avec,C,b,X0,y0,Z0] = ...
randsdp(dense_blk,sparse_blk,diag_blk,m,feas,solve);
if nargin < 6; solve = 0; end;
if nargin < 5; feas = 0; end;
blk = [];
if ~isempty(dense_blk);
for k = 1:length(dense_blk);
blk{k,1} = 's'; blk{k,2} = dense_blk(k);
end;
end;
if ~isempty(sparse_blk);
if size(sparse_blk,1) > size(sparse_blk,2); sparse_blk = sparse_blk'; end;
tmp = size(blk,1);
blk{tmp+1,1} = 's';
blk{tmp+1,2} = sparse_blk;
end;
if ~isempty(diag_blk);
tmp = size(blk,1);
blk{tmp+1,1} = 'l';
blk{tmp+1,2} = diag_blk;
end;
N = size(blk,1);
%%
%% generate X0, Z0
%%
tmp_sp = sparse(sum(sparse_blk));
for L = 1:2
T = [];
if ~isempty(dense_blk);
for k = 1:length(dense_blk);
n = dense_blk(k);
tmp = randn(n);
tmp = tmp*tmp';
tmp = 0.5*(tmp + tmp');
%mineig = min(real(eig(tmp)));
%if (mineig < 0); tmp = tmp - 1.1*mineig*eye(n); end;
if (feas == 2); tmp = eye(n); end;
T{k,1} = tmp;
end;
end;
if ~isempty(sparse_blk);
tmp_sp = sparse(sum(sparse_blk),sum(sparse_blk));
for k = 1:length(sparse_blk);
n = sparse_blk(k);
pos = [sum(sparse_blk(1:k-1))+1 : sum(sparse_blk(1:k))];
tmp = randn(n);
tmp = tmp*tmp';
tmp = 0.5*(tmp + tmp');
%mineig = min(real(eig(tmp)));
%if (mineig < 0); tmp = tmp - 1.1*mineig*eye(n); end;
if (feas == 2); tmp = eye(n); end;
tmp_sp(pos,pos) = sparse(tmp);
end;
T{size(T,1)+1,1} = tmp_sp;
end;
if ~isempty(diag_blk);
if (feas == 2);
T{size(T,1)+1,1} = ones(diag_blk,1);
else;
tmp = randn(diag_blk,1);
tmp = tmp.*tmp;
%mineig = min(tmp);
%if (mineig < 0); tmp = tmp - 1.1*mineig*ones(diag_blk,1); end;
T{size(T,1)+1,1} = tmp;
end;
end;
if (L == 1); X0 = T; else; Z0 = T; end;
end;
%%
%% set up the matrices Ak and b
%%
b = zeros(m,1);
y0 = randn(m,1);
A = cell(N,m);
Ak_sp = sparse(sum(sparse_blk),sum(sparse_blk));
for k = 1:m;
Ak = [];
if ~isempty(dense_blk);
for j = 1:length(dense_blk);
tmp = randn(dense_blk(j)); tmp = 0.5*(tmp+tmp');
Ak{j,1} = tmp;
end;
end;
if ~isempty(sparse_blk);
for j = 1:length(sparse_blk);
n = sparse_blk(j);
tmp = randn(n); tmp = 0.5*(tmp+tmp');
pos = [sum(sparse_blk(1:j-1))+1 : sum(sparse_blk(1:j))];
Ak_sp(pos,pos) = tmp;
end;
Ak{size(Ak,1)+1,1} = Ak_sp;
end;
if ~isempty(diag_blk);
Ak{size(Ak,1)+1,1} = randn(diag_blk,1);
end;
A(:,k) = Ak;
b(k) = blktrace(blk,Ak,X0);
end;
C = ops(Z0,'+',Asum(blk,A,y0));
%%
%% infeasible initial iterate
%%
Avec = svec(blk,A,ones(size(blk,1),1));
if (feas == 0);
[X0,y0,Z0] = infeaspt(blk,Avec,C,b);
end;
%%
if (solve);
[obj,X,y,Z] = sqlp(blk,Avec,C,b,[],X0,y0,Z0);
end;
%%=================================================