table of contents
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/LIN/xlaenv.f(3) | Library Functions Manual | /home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/LIN/xlaenv.f(3) |
NAME¶
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/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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