Base<Field> ProductLanczosDecomp
( const DistSparseMatrix<Field>& A,
DistMultiVec<Field>& V,
AbstractDistMatrix<Base<Field>>& T,
DistMultiVec<Field>& v,
Int basisSize )
{
EL_DEBUG_CSE
const Int m = A.Height();
const Int n = A.Width();
mpi::Comm comm = A.Comm();
DistMultiVec<Field> S(comm);
// Cache the adjoint
// -----------------
DistSparseMatrix<Field> AAdj(comm);
Adjoint( A, AAdj );
if( m >= n )
{
auto applyA =
[&]( const DistMultiVec<Field>& X, DistMultiVec<Field>& Y )
{
Zeros( S, m, X.Width() );
Multiply( NORMAL, Field(1), A, X, Field(0), S );
Zeros( Y, n, X.Width() );
Multiply( NORMAL, Field(1), AAdj, S, Field(0), Y );
};
return LanczosDecomp( n, applyA, V, T, v, basisSize );
}
else
{
auto applyA =
[&]( const DistMultiVec<Field>& X, DistMultiVec<Field>& Y )
{
Zeros( S, n, X.Width() );
Multiply( NORMAL, Field(1), AAdj, X, Field(0), S );
Zeros( Y, m, X.Width() );
Multiply( NORMAL, Field(1), A, S, Field(0), Y );
};
return LanczosDecomp( m, applyA, V, T, v, basisSize );
}
}
Base<F> LanczosDecomp
( const DistSparseMatrix<F>& A,
DistMultiVec<F>& V,
ElementalMatrix<Base<F>>& T,
DistMultiVec<F>& v,
Int basisSize )
{
DEBUG_CSE
const Int n = A.Height();
if( n != A.Width() )
LogicError("A was not square");
auto applyA =
[&]( const DistMultiVec<F>& X, DistMultiVec<F>& Y )
{
Zeros( Y, n, X.Width() );
Multiply( NORMAL, F(1), A, X, F(0), Y );
};
return LanczosDecomp( n, applyA, V, T, v, basisSize );
}
Base<Field> LanczosDecomp
( const SparseMatrix<Field>& A,
Matrix<Field>& V,
Matrix<Base<Field>>& T,
Matrix<Field>& v,
Int basisSize )
{
EL_DEBUG_CSE
const Int n = A.Height();
if( n != A.Width() )
LogicError("A was not square");
auto applyA =
[&]( const Matrix<Field>& X, Matrix<Field>& Y )
{
Zeros( Y, n, X.Width() );
Multiply( NORMAL, Field(1), A, X, Field(0), Y );
};
return LanczosDecomp( n, applyA, V, T, v, basisSize );
}
