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psdinvjmul.c
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Tue, Jul 15, 19:05

psdinvjmul.c

/*
% z = psdinvjmul(xlab,xfrm, y, K)
% PSDINVJMUL solves x jmul z = y, with x = XFRM*diag(xlab)*XFRM'
%
% SEE ALSO sedumi
% ********** INTERNAL FUNCTION OF SEDUMI **********
function z = psdinvjmul(xlab,xfrm, y, K)
% 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 "mex.h"
#include "blksdp.h"
#include "reflect.h"
/* z = psdinvjmul(xlab,xfrm, y, K) */
#define Z_OUT plhs[0]
#define NPAROUT 1
#define X_IN prhs[0]
#define FRM_IN prhs[1]
#define Y_IN prhs[2]
#define K_IN prhs[3]
#define NPARIN 4
/* ============================================================
PSD: z(i.j) = 2*y(i,j)/(xi + xj) (Z and Y are matrices, x is vector)
============================================================ */
/* ************************************************************
PROCEDURE diagjdiv - yij := 2*y(i,j)/(xi + xj) for i >= j.
The strict upper triangular of Y is left unchanged.
INPUT
x - length n vector
n - order of x and square y matrix
UPDATED
y - full n x n, on return tril(yNEW) = 2*y(i,j)/(xi + xj), i >= j.
************************************************************ */
void diagjdiv(double *y,const double *x,const mwIndex n)
{
mwIndex i,j;
double xj;
/* ------------------------------------------------------------
For j=0..n-1:
for i=j..n-1: let y(i,j) *= 2/(xi + xj)
------------------------------------------------------------ */
for(j = 0; j < n; y+=n, j++){
xj = x[j];
y[j] /= xj;
for(i = j+1; i < n; i++)
y[i] *= 2 / (x[i] + xj);
}
}
/* ************************************************************
PROCEDURE psdinvjmul
INPUT
frms lenud+hLen-vector: contains coded orthogonal matrix "Q" for
each PSD block, listed in sdpNL. Eigvecs of X.
x sum(K.s)-vector: contains eigenvalues, so that X = Q*LAB*Q'.
y lenud-vector: full matrix for each PSD block.
sdpNL sdpN-array: order of each PSD block, i.e. K.s.
rsdpN number of real symmetric blocks: 0<= rsdpN <= sdpN.
sdpN number of PSD blocks, i.e. length(K.s).
OUTPUT:
z lenud-vector. On ouput, X*Z+Z*X = 2 * Y.
WORKING ARRAY:
fwork length max(rmaxn,2*hmaxn).
************************************************************ */
void psdinvjmul(double *z, const double *frms, const double *x,
const double *y, const mwIndex *sdpNL,const mwIndex rsdpN,
const mwIndex sdpN, double *fwork)
{
mwIndex k,nk,nksqr;
const double *beta;
/* ------------------------------------------------------------
PSD: Since X = Q'*diag(x)*Q, we have XZ+ZX = 2Y iff
qzqt(i,j) = 2*qyqt(i,j)/(xi + xj), qzqt = Q*z*Q', qyqt = Q*y*Q'.
------------------------------------------------------------ */
for(k = 0; k < rsdpN; k++){
nk = sdpNL[k];
nksqr = SQR(nk);
/* ------------------------------------------------------------
Let z = Q*y*Q'
------------------------------------------------------------ */
memcpy(z, y, nksqr * sizeof(double));
beta = frms + nksqr - nk; /* beta = frms(:,end) */
qxqt(z, beta, frms, nk, fwork);
/* ------------------------------------------------------------
Solve diag(x) jmul zNEW = zOLD
------------------------------------------------------------ */
diagjdiv(z,x,nk);
/* ------------------------------------------------------------
Let zFINAL = Q'*z*Q (back into old eig-basis)
------------------------------------------------------------ */
qtxq(z, beta, frms, nk, fwork);
tril2sym(z,nk);
z += nksqr; y += nksqr; frms += nksqr;
x += nk;
}
for(; k < sdpN; k++){ /* complex Hermitian */
nk = sdpNL[k];
nksqr = SQR(nk);
/* ------------------------------------------------------------
Let z = Q*y*Q'
------------------------------------------------------------ */
memcpy(z, y, 2 * nksqr * sizeof(double));
beta = frms + 2 * nksqr; /* beta = frms(:,2*n+1) */
prpiqxqt(z,z+nksqr, beta, frms,frms+nksqr, nk, fwork);
/* ------------------------------------------------------------
Solve diag(x) jmul zNEW = zOLD. Since x is real, we can handle
the real and imaginary parts seperately.
------------------------------------------------------------ */
diagjdiv(z,x,nk); /* real part */
diagjdiv(z+nksqr,x,nk); /* imaginary part */
/* ------------------------------------------------------------
Let zFINAL = Q'*z*Q (back into old eig-basis)
------------------------------------------------------------ */
prpiqtxq(z,z+nksqr, beta, frms,frms+nksqr, nk, fwork);
tril2herm(z,z+nksqr,nk);
nksqr += nksqr;
z += nksqr; y += nksqr; frms += nksqr + nk; /* skip also beta. */
x += nk;
}
}
/* ============================================================
MAIN: MEXFUNCTION
============================================================ */
/* ************************************************************
PROCEDURE mexFunction - Entry for Matlab
************************************************************ */
void mexFunction(const int nlhs, mxArray *plhs[],
const int nrhs, const mxArray *prhs[])
{
mwIndex i, lenfull, lendiag, lenud, qsize;
double *z, *fwork;
const double *x,*y, *frms;
mwIndex *sdpNL;
coneK cK;
/* ------------------------------------------------------------
Check for proper number of arguments
------------------------------------------------------------ */
mxAssert(nrhs >= NPARIN, "psdinvjmul requires more input arguments.");
mxAssert(nlhs <= NPAROUT, "psdinvjmul generates 1 output argument.");
/* ------------------------------------------------------------
Disassemble cone K structure
------------------------------------------------------------ */
conepars(K_IN, &cK);
/* ------------------------------------------------------------
Get statistics of cone K structure
------------------------------------------------------------ */
lenud = cK.rDim + cK.hDim;
qsize = lenud + cK.hLen;
lenfull = cK.lpN + cK.qDim + lenud;
lendiag = cK.lpN + 2 * cK.lorN + cK.rLen + cK.hLen;
/* ------------------------------------------------------------
Get inputs x, frm, y.
------------------------------------------------------------ */
mxAssert(!mxIsSparse(X_IN) && !mxIsSparse(Y_IN), "Sparse inputs not supported by this version of psdinvjmul.");
x = mxGetPr(X_IN); /* get x and y */
y = mxGetPr(Y_IN);
if(mxGetM(Y_IN) * mxGetN(Y_IN) != lenud){
mxAssert(mxGetM(Y_IN) * mxGetN(Y_IN) == lenfull, "size y mismatch.");
y += cK.lpN + cK.qDim; /* point to PSD */
}
if(mxGetM(X_IN) * mxGetN(X_IN) != cK.rLen + cK.hLen){
mxAssert(mxGetM(X_IN) * mxGetN(X_IN) == lendiag, "size xlab mismatch.");
x += cK.lpN + 2 * cK.lorN; /* point to PSD */
}
mxAssert(mxGetM(FRM_IN) * mxGetN(FRM_IN) == qsize, "size xfrm mismatch.");
frms = mxGetPr(FRM_IN);
/* ------------------------------------------------------------
Allocate output Z
------------------------------------------------------------ */
Z_OUT = mxCreateDoubleMatrix(lenud, (mwIndex)1, mxREAL);
z = mxGetPr(Z_OUT);
/* ------------------------------------------------------------
Allocate working array fwork(max(rmaxn,2*hmaxn))
integer working array sdpNL(sdpN).
------------------------------------------------------------ */
fwork = (double *) mxCalloc(MAX(1,MAX(cK.rMaxn,2*cK.hMaxn)),sizeof(double));
sdpNL = (mwIndex *) mxCalloc(MAX(1,cK.sdpN), sizeof(mwIndex));
/* ------------------------------------------------------------
double to integer
------------------------------------------------------------ */
for(i = 0; i < cK.sdpN; i++)
sdpNL[i] = (mwIndex) cK.sdpNL[i];
psdinvjmul(z,frms,x,y,sdpNL,cK.rsdpN,cK.sdpN, fwork);
/* ------------------------------------------------------------
Release working array
------------------------------------------------------------ */
mxFree(sdpNL);
mxFree(fwork);
}

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