TESTING/LIN/sqrt14.f(3)

NAME
TESTING/LIN/sqrt14.f

SYNOPSIS

  Functions/Subroutines
real function sqrt14 (trans, m, n, nrhs, a, lda, x, ldx, work, lwork)
SQRT14

Function/Subroutine Documentation

  real function sqrt14 (character trans, integer m, integer n, integer nrhs, real, dimension( lda, * ) a, integer lda, real, dimension( ldx, * ) x, integer ldx, real, dimension( lwork ) work, integer lwork)

SQRT14

Purpose:

    !>
    !> SQRT14 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 REAL array, dimension (LDA,N)
    !>          The M-by-N matrix A.
    !>

    LDA

    !>          LDA is INTEGER
    !>          The leading dimension of the array A.
    !>

    X

    !>          X is REAL 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 REAL 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 sqrt14.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.