There is one prototype of bdsqr
available, please see below.
bdsqr( const char uplo, const int_t n, VectorD& d, VectorE& e, MatrixVT& vt, MatrixU& u, MatrixC& c );
bdsqr (short for $FRIENDLY_NAME)
provides a C++ interface to LAPACK routines SBDSQR, DBDSQR, CBDSQR, and
ZBDSQR. bdsqr computes
the singular values and, optionally, the right and/or left singular vectors
from the singular value decomposition (SVD) of a real N-by-N (upper or
lower) bidiagonal matrix B using the implicit zero-shift QR algorithm.
The SVD of B has the form
B = Q * S * P**H
where S is the diagonal matrix of singular values, Q is an orthogonal matrix of left singular vectors, and P is an orthogonal matrix of right singular vectors. If left singular vectors are requested, this subroutine actually returns UQ instead of Q, and, if right singular vectors are requested, this subroutine returns PH*VT instead of P*H, for given complex input matrices U and VT. When U and VT are the unitary matrices that reduce a general matrix A to bidiagonal form: A = U*B*VT, as computed by ZGEBRD, then
A = (UQ) * S * (P*H*VT)
is the SVD of A. Optionally, the subroutine may also compute Q**H*C for a given complex input matrix C.
See "Computing Small Singular Values of Bidiagonal Matrices With Guaranteed High Relative Accuracy," by J. Demmel and W. Kahan, LAPACK Working Note #3 (or SIAM J. Sci. Statist. Comput. vol. 11, no. 5, pp. 873-912, Sept 1990) and "Accurate singular values and differential qd algorithms," by B. Parlett and V. Fernando, Technical Report CPAM-554, Mathematics Department, University of California at Berkeley, July 1992 for a detailed description of the algorithm.
The selection of the LAPACK routine is done during compile-time, and
is determined by the type of values contained in type VectorD.
The type of values is obtained through the value_type
meta-function typename value_type<VectorD>::type. The dispatching table below illustrates
to which specific routine the code path will be generated.
Table 1.217. Dispatching of bdsqr
|
Value type of VectorD |
LAPACK routine |
|---|---|
|
|
SBDSQR |
|
|
DBDSQR |
|
|
CBDSQR |
|
|
ZBDSQR |
Defined in header boost/numeric/bindings/lapack/computational/bdsqr.hpp.
Parameters
The definition of term 1
The definition of term 2
The definition of term 3.
Definitions may contain paragraphs.
#include <boost/numeric/bindings/lapack/computational/bdsqr.hpp> using namespace boost::numeric::bindings; lapack::bdsqr( x, y, z );
this will output
[5] 0 1 2 3 4 5