Exemplo n.º 1
0
inline void
GolubReinschUpper_FLA
( DistMatrix<F>& A, DistMatrix<BASE(F),VR,STAR>& s, DistMatrix<F>& V )
{
#ifndef RELEASE
    CallStackEntry entry("svd::GolubReinschUpper_FLA");
#endif
    typedef BASE(F) Real;
    const Int m = A.Height();
    const Int n = A.Width();
    const Int k = Min( m, n );
    const Int offdiagonal = ( m>=n ? 1 : -1 );
    const Grid& g = A.Grid();

    // Bidiagonalize A
    DistMatrix<F,STAR,STAR> tP(g), tQ(g);
    Bidiag( A, tP, tQ );

    // Grab copies of the diagonal and sub/super-diagonal of A
    DistMatrix<Real,MD,STAR> d_MD_STAR(g), e_MD_STAR(g);
    A.GetRealPartOfDiagonal( d_MD_STAR );
    A.GetRealPartOfDiagonal( e_MD_STAR, offdiagonal );

    // In order to use serial QR kernels, we need the full bidiagonal matrix
    // on each process
    DistMatrix<Real,STAR,STAR> d_STAR_STAR( d_MD_STAR ),
                               e_STAR_STAR( e_MD_STAR );

    // Initialize U and VAdj to the appropriate identity matrices
    DistMatrix<F,VC,STAR> U_VC_STAR(g), V_VC_STAR(g);
    U_VC_STAR.AlignWith( A );
    V_VC_STAR.AlignWith( V );
    Identity( U_VC_STAR, m, k );
    Identity( V_VC_STAR, n, k );

    FlaSVD
    ( k, U_VC_STAR.LocalHeight(), V_VC_STAR.LocalHeight(),
      d_STAR_STAR.Buffer(), e_STAR_STAR.Buffer(),
      U_VC_STAR.Buffer(), U_VC_STAR.LDim(),
      V_VC_STAR.Buffer(), V_VC_STAR.LDim() );

    // Make a copy of A (for the Householder vectors) and pull the necessary 
    // portions of U and V into a standard matrix dist.
    DistMatrix<F> B( A );
    if( m >= n )
    {
        DistMatrix<F> AT(g), AB(g);
        DistMatrix<F,VC,STAR> UT_VC_STAR(g), UB_VC_STAR(g);
        PartitionDown( A, AT, AB, n );
        PartitionDown( U_VC_STAR, UT_VC_STAR, UB_VC_STAR, n );
        AT = UT_VC_STAR;
        MakeZeros( AB );
        V = V_VC_STAR;
    }
    else
    {
        DistMatrix<F> VT(g), VB(g);
        DistMatrix<F,VC,STAR> VT_VC_STAR(g), VB_VC_STAR(g);
        PartitionDown( V, VT, VB, m );
        PartitionDown( V_VC_STAR, VT_VC_STAR, VB_VC_STAR, m );
        VT = VT_VC_STAR;
        MakeZeros( VB );
    }

    // Backtransform U and V
    bidiag::ApplyU( LEFT, NORMAL, B, tQ, A );
    bidiag::ApplyV( LEFT, NORMAL, B, tP, V );

    // Copy out the appropriate subset of the singular values
    s = d_STAR_STAR;
}
Exemplo n.º 2
0
inline void
SimpleSVDUpper
( DistMatrix<Complex<double> >& A,
  DistMatrix<double,VR,STAR>& s,
  DistMatrix<Complex<double> >& V )
{
#ifndef RELEASE
    PushCallStack("svd::SimpleSVDUpper");
#endif
    typedef double Real;
    typedef Complex<Real> C;

    const int m = A.Height();
    const int n = A.Width();
    const int k = std::min( m, n );
    const int offdiagonal = ( m>=n ? 1 : -1 );
    const char uplo = ( m>=n ? 'U' : 'L' );
    const Grid& g = A.Grid();

    // Bidiagonalize A
    DistMatrix<C,STAR,STAR> tP( g ), tQ( g );
    Bidiag( A, tP, tQ );

    // Grab copies of the diagonal and sub/super-diagonal of A
    DistMatrix<Real,MD,STAR> d_MD_STAR( g ),
                             e_MD_STAR( g );
    A.GetRealPartOfDiagonal( d_MD_STAR );
    A.GetRealPartOfDiagonal( e_MD_STAR, offdiagonal );

    // In order to use serial QR kernels, we need the full bidiagonal matrix
    // on each process
    DistMatrix<Real,STAR,STAR> d_STAR_STAR( d_MD_STAR ),
                               e_STAR_STAR( e_MD_STAR );

    // Initialize U and VAdj to the appropriate identity matrices
    DistMatrix<C,VC,STAR> U_VC_STAR( g );
    DistMatrix<C,VC,STAR> V_VC_STAR( g );
    U_VC_STAR.AlignWith( A );
    V_VC_STAR.AlignWith( V );
    Identity( m, k, U_VC_STAR );
    Identity( n, k, V_VC_STAR );

    // Compute the SVD of the bidiagonal matrix and accumulate the Givens
    // rotations into our local portion of U and V
    // NOTE: This _only_ works in the case where m >= n
    const int numAccum = 32;
    const int maxNumIts = 30;
    const int bAlg = 512;
    std::vector<C> GBuffer( (k-1)*numAccum ),
                   HBuffer( (k-1)*numAccum );
    FLA_Bsvd_v_opz_var1
    ( k, U_VC_STAR.LocalHeight(), V_VC_STAR.LocalHeight(), 
      numAccum, maxNumIts,
      d_STAR_STAR.LocalBuffer(), 1,
      e_STAR_STAR.LocalBuffer(), 1,
      &GBuffer[0], 1, k-1,
      &HBuffer[0], 1, k-1,
      U_VC_STAR.LocalBuffer(), 1, U_VC_STAR.LocalLDim(),
      V_VC_STAR.LocalBuffer(), 1, V_VC_STAR.LocalLDim(),
      bAlg );

    // Make a copy of A (for the Householder vectors) and pull the necessary 
    // portions of U and V into a standard matrix dist.
    DistMatrix<C> B( A );
    if( m >= n )
    {
        DistMatrix<C> AT( g ),
                      AB( g );
        DistMatrix<C,VC,STAR> UT_VC_STAR( g ), 
                              UB_VC_STAR( g );
        PartitionDown( A, AT,
                          AB, n );
        PartitionDown( U_VC_STAR, UT_VC_STAR,
                                  UB_VC_STAR, n );
        AT = UT_VC_STAR;
        MakeZeros( AB );
        V = V_VC_STAR;
    }
    else
    {
        DistMatrix<C> VT( g ), 
                      VB( g );
        DistMatrix<C,VC,STAR> VT_VC_STAR( g ), 
                              VB_VC_STAR( g );
        PartitionDown( V, VT, 
                          VB, m );
        PartitionDown
        ( V_VC_STAR, VT_VC_STAR, 
                     VB_VC_STAR, m );
        VT = VT_VC_STAR;
        MakeZeros( VB );
    }

    // Backtransform U and V
    if( m >= n )
    {
        ApplyPackedReflectors
        ( LEFT, LOWER, VERTICAL, BACKWARD, UNCONJUGATED, 0, B, tQ, A );
        ApplyPackedReflectors
        ( LEFT, UPPER, HORIZONTAL, BACKWARD, UNCONJUGATED, 1, B, tP, V );
    }
    else
    {
        ApplyPackedReflectors
        ( LEFT, LOWER, VERTICAL, BACKWARD, UNCONJUGATED, -1, B, tQ, A );
        ApplyPackedReflectors
        ( LEFT, UPPER, HORIZONTAL, BACKWARD, UNCONJUGATED, 0, B, tP, V );
    }

    // Copy out the appropriate subset of the singular values
    s = d_STAR_STAR;
#ifndef RELEASE
    PopCallStack();
#endif
}