TESTING/LIN/dqrt17.f(3)    Library Functions Manual    TESTING/LIN/dqrt17.f(3)

NAME
       TESTING/LIN/dqrt17.f

SYNOPSIS
   Functions/Subroutines
       double precision function dqrt17 (trans, iresid, m, n, nrhs, a, lda, x,
           ldx, b, ldb, c, work, lwork)
           DQRT17

Function/Subroutine Documentation
   double precision function dqrt17 (character trans, integer iresid, integer
       m, integer n, integer nrhs, double precision, dimension( lda, * ) a,
       integer lda, double precision, dimension( ldx, * ) x, integer ldx,
       double precision, dimension( ldb, * ) b, integer ldb, double precision,
       dimension( ldb, * ) c, double precision, dimension( lwork ) work,
       integer lwork)
       DQRT17

       Purpose:


           !>
           !> DQRT17 computes the ratio
           !>
           !>    norm(R**T * op(A)) / ( norm(A) * alpha * max(M,N,NRHS) * EPS ),
           !>
           !> where R = B - op(A)*X, op(A) is A or A**T, depending on TRANS, EPS
           !> is the machine epsilon, and
           !>
           !>    alpha = norm(B) if IRESID = 1 (zero-residual problem)
           !>    alpha = norm(R) if IRESID = 2 (otherwise).
           !>
           !> The norm used is the 1-norm.
           !>

       Parameters
           TRANS

           !>          TRANS is CHARACTER*1
           !>          Specifies whether or not the transpose of A is used.
           !>          = 'N':  No transpose, op(A) = A.
           !>          = 'T':  Transpose, op(A) = A**T.
           !>

           IRESID

           !>          IRESID is INTEGER
           !>          IRESID = 1 indicates zero-residual problem.
           !>          IRESID = 2 indicates non-zero residual.
           !>

           M

           !>          M is INTEGER
           !>          The number of rows of the matrix A.
           !>          If TRANS = 'N', the number of rows of the matrix B.
           !>          If TRANS = 'T', the number of rows of the matrix X.
           !>

           N

           !>          N is INTEGER
           !>          The number of columns of the matrix  A.
           !>          If TRANS = 'N', the number of rows of the matrix X.
           !>          If TRANS = 'T', the number of rows of the matrix B.
           !>

           NRHS

           !>          NRHS is INTEGER
           !>          The number of columns of the matrices X and B.
           !>

           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 >= M.
           !>

           X

           !>          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
           !>          If TRANS = 'N', the n-by-nrhs matrix X.
           !>          If TRANS = 'T', the m-by-nrhs matrix X.
           !>

           LDX

           !>          LDX is INTEGER
           !>          The leading dimension of the array X.
           !>          If TRANS = 'N', LDX >= N.
           !>          If TRANS = 'T', LDX >= M.
           !>

           B

           !>          B is DOUBLE PRECISION array, dimension (LDB,NRHS)
           !>          If TRANS = 'N', the m-by-nrhs matrix B.
           !>          If TRANS = 'T', the n-by-nrhs matrix B.
           !>

           LDB

           !>          LDB is INTEGER
           !>          The leading dimension of the array B.
           !>          If TRANS = 'N', LDB >= M.
           !>          If TRANS = 'T', LDB >= N.
           !>

           C

           !>          C is DOUBLE PRECISION array, dimension (LDB,NRHS)
           !>

           WORK

           !>          WORK is DOUBLE PRECISION array, dimension (LWORK)
           !>

           LWORK

           !>          LWORK is INTEGER
           !>          The length of the array WORK.  LWORK >= NRHS*(M+N).
           !>

       Author
           Univ. of Tennessee


           Univ. of California Berkeley


           Univ. of Colorado Denver


           NAG Ltd.

       Definition at line 151 of file dqrt17.f.

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

LAPACK                          Version 3.12.0         TESTING/LIN/dqrt17.f(3)