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Stability improvement to BCG. Force m_rr hermitian beyond rounding.

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This commit is contained in:
Azusa Yamaguchi 2017-09-04 14:09:47 +01:00
parent d9cd4f0273
commit b83b2b1415
1 changed files with 13 additions and 7 deletions
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20
lib/algorithms/iterative/BlockConjugateGradient.h
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@ -87,15 +87,22 @@ void ThinQRfact (Eigen::MatrixXcd &m_rr,
////////////////////////////////////////////////////////////////////////////////////////////////////
sliceInnerProductMatrix(m_rr,R,R,Orthog);
////////////////////////////////////////////////////////////////////////////////////////////////////
// Cholesky from Eigen
// There exists a ldlt that is documented as more stable
////////////////////////////////////////////////////////////////////////////////////////////////////
Eigen::MatrixXcd L = m_rr.llt().matrixL();
// Force manifest hermitian to avoid rounding related
m_rr = 0.5*(m_rr+m_rr.adjoint());
#if 0
std::cout << " Calling Cholesky ldlt on m_rr " << m_rr <<std::endl;
Eigen::MatrixXcd L_ldlt = m_rr.ldlt().matrixL();
std::cout << " Called Cholesky ldlt on m_rr " << L_ldlt <<std::endl;
auto D_ldlt = m_rr.ldlt().vectorD();
std::cout << " Called Cholesky ldlt on m_rr " << D_ldlt <<std::endl;
#endif
// std::cout << " Calling Cholesky llt on m_rr " <<std::endl;
Eigen::MatrixXcd L = m_rr.llt().matrixL();
// std::cout << " Called Cholesky llt on m_rr " << L <<std::endl;
C = L.adjoint();
Cinv = C.inverse();
////////////////////////////////////////////////////////////////////////////////////////////////////
// Q = R C^{-1}
//
@ -103,7 +110,6 @@ void ThinQRfact (Eigen::MatrixXcd &m_rr,
//
// NB maddMatrix conventions are Right multiplication X[j] a[j,i] already
////////////////////////////////////////////////////////////////////////////////////////////////////
// FIXME:: make a sliceMulMatrix to avoid zero vector
sliceMulMatrix(Q,Cinv,R,Orthog);
}
////////////////////////////////////////////////////////////////////////////////////////////////////