void FlaBidiagSVD
( int k, int mU, int mV, double* d, double* e,
double* U, int ldu, double* V, int ldv,
int numAccum, int maxNumIts, int bAlg )
{
std::vector<Complex<double>> G( (k-1)*numAccum ), H( (k-1)*numAccum );
FLA_Bsvd_v_opd_var1
( k, mU, mV, numAccum, maxNumIts, d, 1, e, 1,
G.data(), 1, k-1, H.data(), 1, k-1, U, 1, ldu, V, 1, ldv, bAlg );
}
inline void
SimpleSVDUpper
( DistMatrix<double>& A,
DistMatrix<double,VR,STAR>& s,
DistMatrix<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
Bidiag( A );
// Grab copies of the diagonal and sub/super-diagonal of A
DistMatrix<Real,MD,STAR> d_MD_STAR( g ),
e_MD_STAR( g );
A.GetDiagonal( d_MD_STAR );
A.GetDiagonal( 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 V to the appropriate identity matrices.
DistMatrix<Real,VC,STAR> U_VC_STAR( g );
DistMatrix<Real,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_opd_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<Real> B( A );
if( m >= n )
{
DistMatrix<Real> AT( g ),
AB( g );
DistMatrix<Real,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<Real> VT( g ),
VB( g );
DistMatrix<Real,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, 0, B, A );
ApplyPackedReflectors
( LEFT, UPPER, HORIZONTAL, BACKWARD, 1, B, V );
}
else
{
ApplyPackedReflectors
( LEFT, LOWER, VERTICAL, BACKWARD, -1, B, A );
ApplyPackedReflectors
( LEFT, UPPER, HORIZONTAL, BACKWARD, 0, B, V );
}
// Copy out the appropriate subset of the singular values
s = d_STAR_STAR;
#ifndef RELEASE
PopCallStack();
#endif
}
