TESTING/LIN/dqrt14.f(3)    Library Functions Manual    TESTING/LIN/dqrt14.f(3)

NAME
       TESTING/LIN/dqrt14.f

SYNOPSIS
   Functions/Subroutines
       double precision function dqrt14 (trans, m, n, nrhs, a, lda, x, ldx,
           work, lwork)
           DQRT14

Function/Subroutine Documentation
   double precision function dqrt14 (character trans, integer m, integer n,
       integer nrhs, double precision, dimension( lda, * ) a, integer lda,
       double precision, dimension( ldx, * ) x, integer ldx, double precision,
       dimension( lwork ) work, integer lwork)
       DQRT14

       Purpose:


            DQRT14 checks whether X is in the row space of A or A'.  It does so
            by scaling both X and A such that their norms are in the range
            [sqrt(eps), 1/sqrt(eps)], then computing a QR factorization of [A,X]
            (if TRANS = 'T') or an LQ factorization of [A',X]' (if TRANS = 'N'),
            and returning the norm of the trailing triangle, scaled by
            MAX(M,N,NRHS)*eps.

       Parameters
           TRANS

                     TRANS is CHARACTER*1
                     = 'N':  No transpose, check for X in the row space of A
                     = 'T':  Transpose, check for X in the row space of A'.

           M

                     M is INTEGER
                     The number of rows of the matrix A.

           N

                     N is INTEGER
                     The number of columns of the matrix A.

           NRHS

                     NRHS is INTEGER
                     The number of right hand sides, i.e., the number of columns
                     of X.

           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.

           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.

           WORK

                     WORK is DOUBLE PRECISION array dimension (LWORK)

           LWORK

                     LWORK is INTEGER
                     length of workspace array required
                     If TRANS = 'N', LWORK >= (M+NRHS)*(N+2);
                     if TRANS = 'T', LWORK >= (N+NRHS)*(M+2).

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 114 of file dqrt14.f.

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

LAPACK                          Version 3.12.0         TESTING/LIN/dqrt14.f(3)