TESTING/EIG/zbdt03.f(3)    Library Functions Manual    TESTING/EIG/zbdt03.f(3)

NAME
       TESTING/EIG/zbdt03.f

SYNOPSIS
   Functions/Subroutines
       subroutine zbdt03 (uplo, n, kd, d, e, u, ldu, s, vt, ldvt, work, resid)
           ZBDT03

Function/Subroutine Documentation
   subroutine zbdt03 (character uplo, integer n, integer kd, double precision,
       dimension( * ) d, double precision, dimension( * ) e, complex*16,
       dimension( ldu, * ) u, integer ldu, double precision, dimension( * ) s,
       complex*16, dimension( ldvt, * ) vt, integer ldvt, complex*16,
       dimension( * ) work, double precision resid)
       ZBDT03

       Purpose:


           !>
           !> ZBDT03 reconstructs a bidiagonal matrix B from its SVD:
           !>    S = U' * B * V
           !> where U and V are orthogonal matrices and S is diagonal.
           !>
           !> The test ratio to test the singular value decomposition is
           !>    RESID = norm( B - U * S * VT ) / ( n * norm(B) * EPS )
           !> where VT = V' and EPS is the machine precision.
           !>

       Parameters
           UPLO

           !>          UPLO is CHARACTER*1
           !>          Specifies whether the matrix B is upper or lower bidiagonal.
           !>          = 'U':  Upper bidiagonal
           !>          = 'L':  Lower bidiagonal
           !>

           N

           !>          N is INTEGER
           !>          The order of the matrix B.
           !>

           KD

           !>          KD is INTEGER
           !>          The bandwidth of the bidiagonal matrix B.  If KD = 1, the
           !>          matrix B is bidiagonal, and if KD = 0, B is diagonal and E is
           !>          not referenced.  If KD is greater than 1, it is assumed to be
           !>          1, and if KD is less than 0, it is assumed to be 0.
           !>

           D

           !>          D is DOUBLE PRECISION array, dimension (N)
           !>          The n diagonal elements of the bidiagonal matrix B.
           !>

           E

           !>          E is DOUBLE PRECISION array, dimension (N-1)
           !>          The (n-1) superdiagonal elements of the bidiagonal matrix B
           !>          if UPLO = 'U', or the (n-1) subdiagonal elements of B if
           !>          UPLO = 'L'.
           !>

           U

           !>          U is COMPLEX*16 array, dimension (LDU,N)
           !>          The n by n orthogonal matrix U in the reduction B = U'*A*P.
           !>

           LDU

           !>          LDU is INTEGER
           !>          The leading dimension of the array U.  LDU >= max(1,N)
           !>

           S

           !>          S is DOUBLE PRECISION array, dimension (N)
           !>          The singular values from the SVD of B, sorted in decreasing
           !>          order.
           !>

           VT

           !>          VT is COMPLEX*16 array, dimension (LDVT,N)
           !>          The n by n orthogonal matrix V' in the reduction
           !>          B = U * S * V'.
           !>

           LDVT

           !>          LDVT is INTEGER
           !>          The leading dimension of the array VT.
           !>

           WORK

           !>          WORK is COMPLEX*16 array, dimension (2*N)
           !>

           RESID

           !>          RESID is DOUBLE PRECISION
           !>          The test ratio:  norm(B - U * S * V') / ( n * norm(A) * EPS )
           !>

       Author
           Univ. of Tennessee


           Univ. of California Berkeley


           Univ. of Colorado Denver


           NAG Ltd.

       Definition at line 133 of file zbdt03.f.

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

LAPACK                          Version 3.12.0         TESTING/EIG/zbdt03.f(3)