SRC/dgbbrd.f(3)            Library Functions Manual            SRC/dgbbrd.f(3)

NAME
       SRC/dgbbrd.f

SYNOPSIS
   Functions/Subroutines
       subroutine dgbbrd (vect, m, n, ncc, kl, ku, ab, ldab, d, e, q, ldq, pt,
           ldpt, c, ldc, work, info)
           DGBBRD

Function/Subroutine Documentation
   subroutine dgbbrd (character vect, integer m, integer n, integer ncc,
       integer kl, integer ku, double precision, dimension( ldab, * ) ab,
       integer ldab, double precision, dimension( * ) d, double precision,
       dimension( * ) e, double precision, dimension( ldq, * ) q, integer ldq,
       double precision, dimension( ldpt, * ) pt, integer ldpt, double
       precision, dimension( ldc, * ) c, integer ldc, double precision,
       dimension( * ) work, integer info)
       DGBBRD

       Purpose:


            DGBBRD reduces a real general m-by-n band matrix A to upper
            bidiagonal form B by an orthogonal transformation: Q**T * A * P = B.

            The routine computes B, and optionally forms Q or P**T, or computes
            Q**T*C for a given matrix C.

       Parameters
           VECT

                     VECT is CHARACTER*1
                     Specifies whether or not the matrices Q and P**T are to be
                     formed.
                     = 'N': do not form Q or P**T;
                     = 'Q': form Q only;
                     = 'P': form P**T only;
                     = 'B': form both.

           M

                     M is INTEGER
                     The number of rows of the matrix A.  M >= 0.

           N

                     N is INTEGER
                     The number of columns of the matrix A.  N >= 0.

           NCC

                     NCC is INTEGER
                     The number of columns of the matrix C.  NCC >= 0.

           KL

                     KL is INTEGER
                     The number of subdiagonals of the matrix A. KL >= 0.

           KU

                     KU is INTEGER
                     The number of superdiagonals of the matrix A. KU >= 0.

           AB

                     AB is DOUBLE PRECISION array, dimension (LDAB,N)
                     On entry, the m-by-n band matrix A, stored in rows 1 to
                     KL+KU+1. The j-th column of A is stored in the j-th column of
                     the array AB as follows:
                     AB(ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(m,j+kl).
                     On exit, A is overwritten by values generated during the
                     reduction.

           LDAB

                     LDAB is INTEGER
                     The leading dimension of the array A. LDAB >= KL+KU+1.

           D

                     D is DOUBLE PRECISION array, dimension (min(M,N))
                     The diagonal elements of the bidiagonal matrix B.

           E

                     E is DOUBLE PRECISION array, dimension (min(M,N)-1)
                     The superdiagonal elements of the bidiagonal matrix B.

           Q

                     Q is DOUBLE PRECISION array, dimension (LDQ,M)
                     If VECT = 'Q' or 'B', the m-by-m orthogonal matrix Q.
                     If VECT = 'N' or 'P', the array Q is not referenced.

           LDQ

                     LDQ is INTEGER
                     The leading dimension of the array Q.
                     LDQ >= max(1,M) if VECT = 'Q' or 'B'; LDQ >= 1 otherwise.

           PT

                     PT is DOUBLE PRECISION array, dimension (LDPT,N)
                     If VECT = 'P' or 'B', the n-by-n orthogonal matrix P'.
                     If VECT = 'N' or 'Q', the array PT is not referenced.

           LDPT

                     LDPT is INTEGER
                     The leading dimension of the array PT.
                     LDPT >= max(1,N) if VECT = 'P' or 'B'; LDPT >= 1 otherwise.

           C

                     C is DOUBLE PRECISION array, dimension (LDC,NCC)
                     On entry, an m-by-ncc matrix C.
                     On exit, C is overwritten by Q**T*C.
                     C is not referenced if NCC = 0.

           LDC

                     LDC is INTEGER
                     The leading dimension of the array C.
                     LDC >= max(1,M) if NCC > 0; LDC >= 1 if NCC = 0.

           WORK

                     WORK is DOUBLE PRECISION array, dimension (2*max(M,N))

           INFO

                     INFO is INTEGER
                     = 0:  successful exit.
                     < 0:  if INFO = -i, the i-th argument had an illegal value.

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 185 of file dgbbrd.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/dgbbrd.f(3)