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Stub adaptor from Thyra::MultiVectorBase to TSQR. More...
#include <Thyra_TsqrAdaptor.hpp>
Public Member Functions  
TsqrAdaptor (const MV &mv, const Teuchos::RCP< const Teuchos::ParameterList > &plist)  
Constructor.  
void  factorExplicit (MV &A, MV &Q, dense_matrix_type &R) 
Compute QR factorization [Q,R] = qr(A,0)  
int  revealRank (MV &Q, dense_matrix_type &R, const magnitude_type &tol) 
Rankrevealing decomposition.  
Static Public Member Functions  
static Teuchos::RCP< const Teuchos::ParameterList >  getDefaultParameters () 
Default parameters. 
Stub adaptor from Thyra::MultiVectorBase to TSQR.
TSQR (Tall Skinny QR factorization) is an orthogonalization kernel that is as accurate as Householder QR, yet requires only messages between $P$ MPI processes, independently of the number of columns in the multivector.
TSQR works independently of the particular multivector implementation, and interfaces to the latter via an adaptor class. Thyra::TsqrAdaptor is the adaptor class for Thyra::MultiVectorBase. It templates on the MultiVector (MV) type so that it can pick up that class' typedefs. In particular, TSQR chooses its intranode implementation based on the Kokkos Node type of the multivector.
Definition at line 65 of file Thyra_TsqrAdaptor.hpp.
Thyra::TsqrAdaptor< Scalar >::TsqrAdaptor  (  const MV &  mv, 
const Teuchos::RCP< const Teuchos::ParameterList > &  plist  
)  [inline] 
Constructor.
mv  [in] Multivector object, used only to access the underlying communicator object (in this case, Teuchos::Comm<int>, accessed via the Tpetra::Map belonging to the multivector). All multivector objects with which this Adaptor works must use the same map and communicator. 
plist  [in] List of parameters for configuring TSQR. The specific parameter keys that are read depend on the TSQR implementation. "cacheBlockSize" (cache block size per core, in bytes) tends to be defined for all of the nonGPU implementations. For details, check the specific NodeTsqrFactory implementation. 
Definition at line 104 of file Thyra_TsqrAdaptor.hpp.
static Teuchos::RCP<const Teuchos::ParameterList> Thyra::TsqrAdaptor< Scalar >::getDefaultParameters  (  )  [inline, static] 
Default parameters.
Return default parameters for the TSQR variant used by Epetra.
Definition at line 85 of file Thyra_TsqrAdaptor.hpp.
void Thyra::TsqrAdaptor< Scalar >::factorExplicit  (  MV &  A, 
MV &  Q,  
dense_matrix_type &  R  
)  [inline] 
Compute QR factorization [Q,R] = qr(A,0)
Definition at line 113 of file Thyra_TsqrAdaptor.hpp.
int Thyra::TsqrAdaptor< Scalar >::revealRank  (  MV &  Q, 
dense_matrix_type &  R,  
const magnitude_type &  tol  
)  [inline] 
Rankrevealing decomposition.
Using the R factor and explicit Q factor from factorExplicit(), compute the singular value decomposition (SVD) of R ( ). If R is full rank (with respect to the given relative tolerance tol), don't change Q or R. Otherwise, compute and in place (the latter may be no longer upper triangular).
Q  [in/out] On input: explicit Q factor computed by factorExplicit(). (Must be an orthogonal resp. unitary matrix.) On output: If R is of full numerical rank with respect to the tolerance tol, Q is unmodified. Otherwise, Q is updated so that the first rank columns of Q are a basis for the column space of A (the original matrix whose QR factorization was computed by factorExplicit()). The remaining columns of Q are a basis for the null space of A. 
R  [in/out] On input: ncols by ncols upper triangular matrix with leading dimension ldr >= ncols. On output: if input is full rank, R is unchanged on output. Otherwise, if is the SVD of R, on output R is overwritten with $ V^*$. This is also an ncols by ncols matrix, but may not necessarily be upper triangular. 
tol  [in] Relative tolerance for computing the numerical rank of the matrix R. 
Definition at line 152 of file Thyra_TsqrAdaptor.hpp.