TESTING/EIG/dbdt01.f(3)

NAME
TESTING/EIG/dbdt01.f

SYNOPSIS

  Functions/Subroutines
subroutine dbdt01 (m, n, kd, a, lda, q, ldq, d, e, pt, ldpt, work, resid)
DBDT01

Function/Subroutine Documentation

  subroutine dbdt01 (integer m, integer n, integer kd, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldq, * ) q, integer ldq, double precision, dimension( * ) d, double precision, dimension( * ) e, double precision, dimension( ldpt, * ) pt, integer ldpt, double precision, dimension( * ) work, double precision resid)

DBDT01

Purpose:

     DBDT01 reconstructs a general matrix A from its bidiagonal form
        A = Q * B * P**T
     where Q (m by min(m,n)) and P**T (min(m,n) by n) are orthogonal
     matrices and B is bidiagonal.
     The test ratio to test the reduction is
        RESID = norm(A - Q * B * P**T) / ( n * norm(A) * EPS )
     where EPS is the machine precision.

Parameters
    M

              M is INTEGER
              The number of rows of the matrices A and Q.

    N

              N is INTEGER
              The number of columns of the matrices A and P**T.

    KD

              KD is INTEGER
              If KD = 0, B is diagonal and the array E is not referenced.
              If KD = 1, the reduction was performed by xGEBRD; B is upper
              bidiagonal if M >= N, and lower bidiagonal if M < N.
              If KD = -1, the reduction was performed by xGBBRD; B is
              always upper bidiagonal.

    A

              A is DOUBLE PRECISION array, dimension (LDA,N)
              The m by n matrix A.

    LDA

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max(1,M).

    Q

              Q is DOUBLE PRECISION array, dimension (LDQ,N)
              The m by min(m,n) orthogonal matrix Q in the reduction
              A = Q * B * P**T.

    LDQ

              LDQ is INTEGER
              The leading dimension of the array Q.  LDQ >= max(1,M).

    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 if
              m >= n, or the subdiagonal elements of B if m < n.

    PT

              PT is DOUBLE PRECISION array, dimension (LDPT,N)
              The min(m,n) by n orthogonal matrix P**T in the reduction
              A = Q * B * P**T.

    LDPT

              LDPT is INTEGER
              The leading dimension of the array PT.
              LDPT >= max(1,min(M,N)).

    WORK

              WORK is DOUBLE PRECISION array, dimension (M+N)

    RESID

              RESID is DOUBLE PRECISION
              The test ratio:
              norm(A - Q * B * P**T) / ( n * norm(A) * EPS )

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 139 of file dbdt01.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.