tstiee (l) - Linux Manuals

tstiee: called from the LAPACK routines to choose problem-dependent parameters for the local environment

NAME

TSTIEE - called from the LAPACK routines to choose problem-dependent parameters for the local environment

SYNOPSIS

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 problem-dependent 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 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

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 k-th 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
 subroutine NAME, in the same order that they appear in the
 argument list for NAME, even if they are not used in determining
 the value of the parameter specified by ISPEC.
2) The problem dimensions N1, N2, N3, N4 are specified in the order
 that they appear in the argument list for NAME.  N1 is used
 first, N2 second, and so on, and unused problem dimensions are
 passed a value of -1.
3) The parameter value returned by ILAENV is checked for validity in
 the calling subroutine.  For example, ILAENV is used to retrieve
 the optimal blocksize for STRTRI as follows:

 NB = ILAENV( 1, aqSTRTRIaq, UPLO // DIAG, N, -1, -1, -1 )
 IF( NB.LE.1 ) NB = MAX( 1, N )