Provided by: liblapack-doc_3.3.1-1_all bug

NAME

       LAPACK-3 - computes the singular values of a real N-by-N bidiagonal matrix with diagonal D
       and off-diagonal E

SYNOPSIS

       SUBROUTINE SLASQ1( N, D, E, WORK, INFO )

           INTEGER        INFO, N

           REAL           D( * ), E( * ), WORK( * )

PURPOSE

       SLASQ1 computes the singular values of a real N-by-N bidiagonal matrix with diagonal D and
       off-diagonal E. The singular values
        are computed to high relative accuracy, in the absence of
        denormalization, underflow and overflow. The algorithm was first
        presented in
        "Accurate singular values and differential qd algorithms" by K. V.
        Fernando and B. N. Parlett, Numer. Math., Vol-67, No. 2, pp. 191-230,
        1994,
        and the present implementation is described in "An implementation of
        the dqds Algorithm (Positive Case)", LAPACK Working Note.

ARGUMENTS

        N     (input) INTEGER
              The number of rows and columns in the matrix. N >= 0.

        D     (input/output) REAL array, dimension (N)
              On entry, D contains the diagonal elements of the
              bidiagonal matrix whose SVD is desired. On normal exit,
              D contains the singular values in decreasing order.

        E     (input/output) REAL array, dimension (N)
              On entry, elements E(1:N-1) contain the off-diagonal elements
              of the bidiagonal matrix whose SVD is desired.
              On exit, E is overwritten.

        WORK  (workspace) REAL array, dimension (4*N)

        INFO  (output) INTEGER
              = 0: successful exit
              < 0: if INFO = -i, the i-th argument had an illegal value
              > 0: the algorithm failed
              = 1, a split was marked by a positive value in E
              = 2, current block of Z not diagonalized after 30*N
              iterations (in inner while loop)
              = 3, termination criterion of outer while loop not met
              (program created more than N unreduced blocks)

 LAPACK routine (version 3.2)               April 2011                            SLASQ1(3lapack)