.TH "TESTING/LIN/xlaenv.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME TESTING/LIN/xlaenv.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBxlaenv\fP (ispec, nvalue)" .br .RI "\fBXLAENV\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine xlaenv (integer ispec, integer nvalue)" .PP \fBXLAENV\fP .PP \fBPurpose:\fP .RS 4 .PP .nf !> !> XLAENV sets certain machine- and problem-dependent quantities !> which will later be retrieved by ILAENV\&. !> .fi .PP .RE .PP \fBParameters\fP .RS 4 \fIISPEC\fP .PP .nf !> 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 !> .fi .PP .br \fINVALUE\fP .PP .nf !> NVALUE is INTEGER !> The value of the parameter specified by ISPEC\&. !> .fi .PP .RE .PP \fBAuthor\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP .PP Definition at line \fB77\fP of file \fBxlaenv\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.