TESTING/LIN/xlaenv.f(3)

NAME
TESTING/LIN/xlaenv.f

SYNOPSIS

  Functions/Subroutines
subroutine xlaenv (ispec, nvalue)
XLAENV

Function/Subroutine Documentation

  subroutine xlaenv (integer ispec, integer nvalue)

XLAENV

Purpose:

    !>
    !> XLAENV sets certain machine- and problem-dependent quantities
    !> which will later be retrieved by ILAENV.
    !>

Parameters
    ISPEC

    !>          ISPEC is INTEGER
    !>          Specifies the parameter to be set in the COMMON array IPARMS.
    !>          = 1: the optimal blocksize; if this value is 1, an unblocked
    !>               algorithm will give the best performance.
    !>          = 2: the minimum block size for which the block routine
    !>               should be used; if the usable block size is less than
    !>               this value, an unblocked routine should be used.
    !>          = 3: the crossover point (in a block routine, for N less
    !>               than this value, an unblocked routine should be used)
    !>          = 4: the number of shifts, used in the nonsymmetric
    !>               eigenvalue routines
    !>          = 5: the minimum column dimension for blocking to be used;
    !>               rectangular blocks must have dimension at least k by m,
    !>               where k is given by ILAENV(2,...) and m by ILAENV(5,...)
    !>          = 6: the crossover point for the SVD (when reducing an m by n
    !>               matrix to bidiagonal form, if max(m,n)/min(m,n) exceeds
    !>               this value, a QR factorization is used first to reduce
    !>               the matrix to a triangular form)
    !>          = 7: the number of processors
    !>          = 8: another crossover point, for the multishift QR and QZ
    !>               methods for nonsymmetric eigenvalue problems.
    !>          = 9: maximum size of the subproblems at the bottom of the
    !>               computation tree in the divide-and-conquer algorithm
    !>               (used by xGELSD and xGESDD)
    !>          =10: ieee NaN arithmetic can be trusted not to trap
    !>          =11: infinity arithmetic can be trusted not to trap
    !>

    NVALUE

    !>          NVALUE is INTEGER
    !>          The value of the parameter specified by ISPEC.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 77 of file xlaenv.f.

Author

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