Classes | |
class | Anasazi::HelperTraits< ScalarType > |
Class which defines basic traits for working with different scalar types. More... | |
class | Anasazi::HelperTraits< ANSZI_CPLX_CLASS< T > > |
Class which defines basic traits for working with different scalar types. More... | |
class | Anasazi::MultiVecTraits< ScalarType, MV > |
Virtual base class which defines basic traits for the multi-vector type. More... | |
class | Anasazi::OperatorTraits< ScalarType, MV, OP > |
Virtual base class which defines basic traits for the operator type. More... |
Anasazi::MultiVecTraits requires two template arguments:
ScalarType
), describing the field over which the multivectors are defined, andMV
).
Because Anasazi implements block eigensolvers, the underlying primitive is a collection of column vectors (a multivector) instead of a single column vector. The purpose of Anasazi::MultiVecTraits is to provide an interface for performing multivector operations (e.g., multivector AXPY
). An example illustrating the manipulation of an Epetra_MultiVector using Anasazi::MultiVecTraits follows:
// build some Epetra_MultiVector objects... Epetra_MultiVector A(...), B(...), C(...); // ...and a Teuchos::SerialDenseMatrix Teuchos::SerialDenseMatrix<int,double> D(...); // perform C <- 1.0*A + 0.5*B; Anasazi::MultiVecTraits<double,Epetra_MultiVector>::MvAddMv(1.0, A, 0.5, B, C); // perform C <- -2.0*A*D + 1.0*C Anasazi::MultiVecTraits<double,Epetra_MultiVector>::MvTimesMatAddMv(-2.0, A, D, 1.0, C);
As is customary among large-scale eigenvalue software, Anasazi assumes matrix-free access to the problem operators, i.e., only matrix-vector products are needed. Therefore, Anasazi::OperatorTraits requires three template arguments:
ScalarType
), describing the field over which the multivectors are defined,MV
), describing the domain and range of the operator, andOP
).
The Anasazi::OperatorTraits interface provides a single mechanism: the ability to apply an operator of type OP
to a multivector of type MV
, yielding another multivector of type MV
. This is performed as follows:
// build some Epetra_MultiVector objects... Epetra_MultiVector A(...), B(...); // ...and an Epetra operator Epetra_Operator Op(...); // apply the operation B <- Op*A Anasazi::OperatorTraits<double,Epetra_MultiVector,Epetra_Operator>::Apply(Op,A,B);
These interfaces are used throughout Anasazi to manipulate multivectors and apply operators, so that no low-level access to the underlying objects are needed. Hence, Anasazi is independent of the underlying linear algebra data structures (e.g., serial or parallel, real or complex). This allows the generic programming of algorithms for the solution of eigenvalue problems.
Calling methods of MultiVecTraits<ScalarType,MV> requires that a specialization of MultiVecTraits has been implemented for classes ScalarType
and MV
. In the case of Epetra_MultiVector and Epetra_Operator (which are both defined on the field of doubles), this specialization is provided by the Anasazi adapters to Epetra. Specializations of these traits classes provided by Anasazi are:
double
)Additional specializations of Anasazi::MultiVecTraits and Anasazi::OperatorTraits may be created by the user for any other multivector and operator class.