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sdmauxTriudot.c
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Mon, Jul 14, 11:51

sdmauxTriudot.c
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/* ************************************************************
MODULE sdmaux*.c -- Several low-level subroutines for the
mex-files in the Self-Dual-Minimization package.
% This file is part of SeDuMi 1.1 by Imre Polik and Oleksandr Romanko
% Copyright (C) 2005 McMaster University, Hamilton, CANADA (since 1.1)
%
% Copyright (C) 2001 Jos F. Sturm (up to 1.05R5)
% Dept. Econometrics & O.R., Tilburg University, the Netherlands.
% Supported by the Netherlands Organization for Scientific Research (NWO).
%
% Affiliation SeDuMi 1.03 and 1.04Beta (2000):
% Dept. Quantitative Economics, Maastricht University, the Netherlands.
%
% Affiliations up to SeDuMi 1.02 (AUG1998):
% CRL, McMaster University, Canada.
% Supported by the Netherlands Organization for Scientific Research (NWO).
%
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program; if not, write to the Free Software
% Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
% 02110-1301, USA
************************************************************ */
#include <string.h>
#include "blksdp.h"
/* ************************************************************
PROCEDURE: triudotprod - Computes trace(X*Y), where X and Y are
supposed to be symmetric; only the triu's are used.
INPUT
x - full n x n, only triu(x) used
y - full n x n, only triu(x) used
n - order
RETURNS the inner product between X and Y, trace(X*Y).
************************************************************ */
double triudotprod(const double *x, const double *y, const mwIndex n)
{
mwIndex i, j;
double z;
if(n <= 0)
return 0.0;
z = x[0] * y[0];
for(j = 1; j < n; j++){
x += n; y += n; /* point to x(:,j) and y(:,j) */
z += 2 * realdot(x,y,j) + x[j] * y[j];
}
return z;
}
/* striudotprod: z = tr(X*Y), where diag(X)=0. only triu(X,1) and triu(Y,1)
are used. For the imaginary part into the real inner product. */
double striudotprod(const double *x, const double *y, const mwIndex n)
{
mwIndex i, j;
double z;
if(n <= 1)
return 0.0;
z = 0.0;
for(j = 1; j < n; j++){
x += n; y += n; /* point to x(:,j) and y(:,j) */
z += realdot(x,y,j);
}
return 2 * z;
}

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