tstiee (l)  Linux Man Pages
tstiee: called from the LAPACK routines to choose problemdependent parameters for the local environment
NAME
TSTIEE  called from the LAPACK routines to choose problemdependent parameters for the local environmentSYNOPSIS
 PROGRAM MAIN
 INTEGER ILAENV
 EXTERNAL ILAENV
 INTEGER IEEEOK
 WRITE( 6, FMT = * ) aqWe are about to check whether infinity arithmeticaq
 WRITE( 6, FMT = * )aqcan be trusted. If this test hangs, setaq
 WRITE( 6, FMT = * ) aqILAENV = 0 for ISPEC = 10 in LAPACK/SRC/ilaenv.faq
 IEEEOK = ILAENV( 10, aqILAENVaq, aqNaq, 1, 2, 3, 4 )
 WRITE( 6, FMT = * )
 IF( IEEEOK.EQ.0 ) THEN
 WRITE( 6, FMT = * ) aqInfinity arithmetic did not perform per the ieee specaq
 ELSE
 WRITE( 6, FMT = * ) aqInfinity arithmetic performed as per the ieee spec.aq
 WRITE( 6, FMT = * ) aqHowever, this is not an exhaustive test and does notaq
 WRITE( 6, FMT = * ) aqguarantee that infinity arithmetic meets theaq, aq ieee spec.aq
 END IF
 WRITE( 6, FMT = * )
 WRITE( 6, FMT = * ) aqWe are about to check whether NaN arithmeticaq
 WRITE( 6, FMT = * )aqcan be trusted. If this test hangs, setaq
 WRITE( 6, FMT = * ) aqILAENV = 0 for ISPEC = 11 in LAPACK/SRC/ilaenv.faq
 IEEEOK = ILAENV( 11, aqILAENVaq, aqNaq, 1, 2, 3, 4 )
 WRITE( 6, FMT = * )
 IF( IEEEOK.EQ.0 ) THEN
 WRITE( 6, FMT = * ) aqNaN arithmetic did not perform per the ieee specaq
 ELSE
 WRITE( 6, FMT = * )aqNaN arithmetic performed as per the ieeeaq, aq spec.aq
 WRITE( 6, FMT = * ) aqHowever, this is not an exhaustive test and does notaq
 WRITE( 6, FMT = * )aqguarantee that NaN arithmetic meets theaq, aq ieee spec.aq
 END IF
 WRITE( 6, FMT = * )
 END
 INTEGER FUNCTION ILAENV( ISPEC, NAME, OPTS, N1, N2, N3, N4 )
 CHARACTER*( * ) NAME, OPTS
 INTEGER ISPEC, N1, N2, N3, N4
PURPOSE
ILAENV is called from the LAPACK routines to choose problemdependent parameters for the local environment. See ISPEC for a description of the parameters.
This version provides a set of parameters which should give good,
but not optimal, performance on many of the currently available
computers. Users are encouraged to modify this subroutine to set
the tuning parameters for their particular machine using the option
and problem size information in the arguments.
This routine will not function correctly if it is converted to all
lower case. Converting it to all upper case is allowed.
ARGUMENTS
 ISPEC (input) INTEGER

Specifies the parameter to be returned as the value of
ILAENV.
= 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: the 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 divideandconquer 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  NAME (input) CHARACTER*(*)
 The name of the calling subroutine, in either upper case or lower case.
 OPTS (input) CHARACTER*(*)
 The character options to the subroutine NAME, concatenated into a single character string. For example, UPLO = aqUaq, TRANS = aqTaq, and DIAG = aqNaq for a triangular routine would be specified as OPTS = aqUTNaq.
 N1 (input) INTEGER

N2 (input) INTEGER
N3 (input) INTEGER
N4 (input) INTEGER
Problem dimensions for the subroutine NAME; these may not all
be required.
>= 0: the value of the parameter specified by ISPEC < 0: if ILAENV = k, the kth argument had an illegal value.
FURTHER DETAILS
The following conventions have been used when calling ILAENV from the LAPACK routines:1) OPTS is a concatenation of all of the character options to
2) The problem dimensions N1, N2, N3, N4 are specified in the order
3) The parameter value returned by ILAENV is checked for validity in