INTEGER FUNCTION ILAENV( ISPEC, NAME, OPTS, N1, N2, N3, N4 ) 7,3
!
! -- LAPACK auxiliary routine (version 3.1.1) --
! Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
! January 2007
!
! .. Scalar Arguments ..
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.
!
! ILAENV returns an INTEGER
! if ILAENV >= 0: ILAENV returns the value of the parameter specified by ISPEC
! if ILAENV < 0: if ILAENV = -k, the k-th argument had an illegal value.
!
! 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 (DEPRECATED)
! = 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 method
! for nonsymmetric eigenvalue problems (DEPRECATED)
! = 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
! 12 <= ISPEC <= 16:
! xHSEQR or one of its subroutines,
! see IPARMQ for detailed explanation
!
! 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 = 'U',
! TRANS = 'T', and DIAG = 'N' for a triangular routine would
! be specified as OPTS = 'UTN'.
!
! N1 (input) INTEGER
! N2 (input) INTEGER
! N3 (input) INTEGER
! N4 (input) INTEGER
! Problem dimensions for the subroutine NAME; these may not all
! be required.
!
! 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, 'STRTRI', UPLO // DIAG, N, -1, -1, -1 )
! IF( NB.LE.1 ) NB = MAX( 1, N )
!
! =====================================================================
!
! .. Local Scalars ..
INTEGER I, IC, IZ, NB, NBMIN, NX
LOGICAL CNAME, SNAME
CHARACTER C1*1, C2*2, C4*2, C3*3, SUBNAM*6
! ..
! .. Intrinsic Functions ..
INTRINSIC CHAR, ICHAR, INT, MIN, REAL
! ..
! .. External Functions ..
! INTEGER IEEECK, IPARMQ
! EXTERNAL IEEECK, IPARMQ
! ..
! .. Executable Statements ..
!
GO TO ( 10, 10, 10, 80, 90, 100, 110, 120, &
130, 140, 150, 160, 160, 160, 160, 160 )ISPEC
!
! Invalid value for ISPEC
!
ILAENV = -1
RETURN
!
10 CONTINUE
!
! Convert NAME to upper case if the first character is lower case.
!
ILAENV = 1
SUBNAM = NAME
IC = ICHAR( SUBNAM( 1: 1 ) )
IZ = ICHAR( 'Z' )
IF( IZ.EQ.90 .OR. IZ.EQ.122 ) THEN
!
! ASCII character set
!
IF( IC.GE.97 .AND. IC.LE.122 ) THEN
SUBNAM( 1: 1 ) = CHAR( IC-32 )
DO 20 I = 2, 6
IC = ICHAR( SUBNAM( I: I ) )
IF( IC.GE.97 .AND. IC.LE.122 ) &
SUBNAM( I: I ) = CHAR( IC-32 )
20 CONTINUE
END IF
!
ELSE IF( IZ.EQ.233 .OR. IZ.EQ.169 ) THEN
!
! EBCDIC character set
!
IF( ( IC.GE.129 .AND. IC.LE.137 ) .OR. &
( IC.GE.145 .AND. IC.LE.153 ) .OR. &
( IC.GE.162 .AND. IC.LE.169 ) ) THEN
SUBNAM( 1: 1 ) = CHAR( IC+64 )
DO 30 I = 2, 6
IC = ICHAR( SUBNAM( I: I ) )
IF( ( IC.GE.129 .AND. IC.LE.137 ) .OR. &
( IC.GE.145 .AND. IC.LE.153 ) .OR. &
( IC.GE.162 .AND. IC.LE.169 ) )SUBNAM( I: &
I ) = CHAR( IC+64 )
30 CONTINUE
END IF
!
ELSE IF( IZ.EQ.218 .OR. IZ.EQ.250 ) THEN
!
! Prime machines: ASCII+128
!
IF( IC.GE.225 .AND. IC.LE.250 ) THEN
SUBNAM( 1: 1 ) = CHAR( IC-32 )
DO 40 I = 2, 6
IC = ICHAR( SUBNAM( I: I ) )
IF( IC.GE.225 .AND. IC.LE.250 ) &
SUBNAM( I: I ) = CHAR( IC-32 )
40 CONTINUE
END IF
END IF
!
C1 = SUBNAM( 1: 1 )
SNAME = C1.EQ.'S' .OR. C1.EQ.'D'
CNAME = C1.EQ.'C' .OR. C1.EQ.'Z'
IF( .NOT.( CNAME .OR. SNAME ) ) &
RETURN
C2 = SUBNAM( 2: 3 )
C3 = SUBNAM( 4: 6 )
C4 = C3( 2: 3 )
!
GO TO ( 50, 60, 70 )ISPEC
!
50 CONTINUE
!
! ISPEC = 1: block size
!
! In these examples, separate code is provided for setting NB for
! real and complex. We assume that NB will take the same value in
! single or double precision.
!
NB = 1
!
IF( C2.EQ.'GE' ) THEN
IF( C3.EQ.'TRF' ) THEN
IF( SNAME ) THEN
NB = 64
ELSE
NB = 64
END IF
ELSE IF( C3.EQ.'QRF' .OR. C3.EQ.'RQF' .OR. C3.EQ.'LQF' .OR. &
C3.EQ.'QLF' ) THEN
IF( SNAME ) THEN
NB = 32
ELSE
NB = 32
END IF
ELSE IF( C3.EQ.'HRD' ) THEN
IF( SNAME ) THEN
NB = 32
ELSE
NB = 32
END IF
ELSE IF( C3.EQ.'BRD' ) THEN
IF( SNAME ) THEN
NB = 32
ELSE
NB = 32
END IF
ELSE IF( C3.EQ.'TRI' ) THEN
IF( SNAME ) THEN
NB = 64
ELSE
NB = 64
END IF
END IF
ELSE IF( C2.EQ.'PO' ) THEN
IF( C3.EQ.'TRF' ) THEN
IF( SNAME ) THEN
NB = 64
ELSE
NB = 64
END IF
END IF
ELSE IF( C2.EQ.'SY' ) THEN
IF( C3.EQ.'TRF' ) THEN
IF( SNAME ) THEN
NB = 64
ELSE
NB = 64
END IF
ELSE IF( SNAME .AND. C3.EQ.'TRD' ) THEN
NB = 32
ELSE IF( SNAME .AND. C3.EQ.'GST' ) THEN
NB = 64
END IF
ELSE IF( CNAME .AND. C2.EQ.'HE' ) THEN
IF( C3.EQ.'TRF' ) THEN
NB = 64
ELSE IF( C3.EQ.'TRD' ) THEN
NB = 32
ELSE IF( C3.EQ.'GST' ) THEN
NB = 64
END IF
ELSE IF( SNAME .AND. C2.EQ.'OR' ) THEN
IF( C3( 1: 1 ).EQ.'G' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NB = 32
END IF
ELSE IF( C3( 1: 1 ).EQ.'M' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NB = 32
END IF
END IF
ELSE IF( CNAME .AND. C2.EQ.'UN' ) THEN
IF( C3( 1: 1 ).EQ.'G' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NB = 32
END IF
ELSE IF( C3( 1: 1 ).EQ.'M' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NB = 32
END IF
END IF
ELSE IF( C2.EQ.'GB' ) THEN
IF( C3.EQ.'TRF' ) THEN
IF( SNAME ) THEN
IF( N4.LE.64 ) THEN
NB = 1
ELSE
NB = 32
END IF
ELSE
IF( N4.LE.64 ) THEN
NB = 1
ELSE
NB = 32
END IF
END IF
END IF
ELSE IF( C2.EQ.'PB' ) THEN
IF( C3.EQ.'TRF' ) THEN
IF( SNAME ) THEN
IF( N2.LE.64 ) THEN
NB = 1
ELSE
NB = 32
END IF
ELSE
IF( N2.LE.64 ) THEN
NB = 1
ELSE
NB = 32
END IF
END IF
END IF
ELSE IF( C2.EQ.'TR' ) THEN
IF( C3.EQ.'TRI' ) THEN
IF( SNAME ) THEN
NB = 64
ELSE
NB = 64
END IF
END IF
ELSE IF( C2.EQ.'LA' ) THEN
IF( C3.EQ.'UUM' ) THEN
IF( SNAME ) THEN
NB = 64
ELSE
NB = 64
END IF
END IF
ELSE IF( SNAME .AND. C2.EQ.'ST' ) THEN
IF( C3.EQ.'EBZ' ) THEN
NB = 1
END IF
END IF
ILAENV = NB
RETURN
!
60 CONTINUE
!
! ISPEC = 2: minimum block size
!
NBMIN = 2
IF( C2.EQ.'GE' ) THEN
IF( C3.EQ.'QRF' .OR. C3.EQ.'RQF' .OR. C3.EQ.'LQF' .OR. C3.EQ. &
'QLF' ) THEN
IF( SNAME ) THEN
NBMIN = 2
ELSE
NBMIN = 2
END IF
ELSE IF( C3.EQ.'HRD' ) THEN
IF( SNAME ) THEN
NBMIN = 2
ELSE
NBMIN = 2
END IF
ELSE IF( C3.EQ.'BRD' ) THEN
IF( SNAME ) THEN
NBMIN = 2
ELSE
NBMIN = 2
END IF
ELSE IF( C3.EQ.'TRI' ) THEN
IF( SNAME ) THEN
NBMIN = 2
ELSE
NBMIN = 2
END IF
END IF
ELSE IF( C2.EQ.'SY' ) THEN
IF( C3.EQ.'TRF' ) THEN
IF( SNAME ) THEN
NBMIN = 8
ELSE
NBMIN = 8
END IF
ELSE IF( SNAME .AND. C3.EQ.'TRD' ) THEN
NBMIN = 2
END IF
ELSE IF( CNAME .AND. C2.EQ.'HE' ) THEN
IF( C3.EQ.'TRD' ) THEN
NBMIN = 2
END IF
ELSE IF( SNAME .AND. C2.EQ.'OR' ) THEN
IF( C3( 1: 1 ).EQ.'G' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NBMIN = 2
END IF
ELSE IF( C3( 1: 1 ).EQ.'M' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NBMIN = 2
END IF
END IF
ELSE IF( CNAME .AND. C2.EQ.'UN' ) THEN
IF( C3( 1: 1 ).EQ.'G' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NBMIN = 2
END IF
ELSE IF( C3( 1: 1 ).EQ.'M' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NBMIN = 2
END IF
END IF
END IF
ILAENV = NBMIN
RETURN
!
70 CONTINUE
!
! ISPEC = 3: crossover point
!
NX = 0
IF( C2.EQ.'GE' ) THEN
IF( C3.EQ.'QRF' .OR. C3.EQ.'RQF' .OR. C3.EQ.'LQF' .OR. C3.EQ. &
'QLF' ) THEN
IF( SNAME ) THEN
NX = 128
ELSE
NX = 128
END IF
ELSE IF( C3.EQ.'HRD' ) THEN
IF( SNAME ) THEN
NX = 128
ELSE
NX = 128
END IF
ELSE IF( C3.EQ.'BRD' ) THEN
IF( SNAME ) THEN
NX = 128
ELSE
NX = 128
END IF
END IF
ELSE IF( C2.EQ.'SY' ) THEN
IF( SNAME .AND. C3.EQ.'TRD' ) THEN
NX = 32
END IF
ELSE IF( CNAME .AND. C2.EQ.'HE' ) THEN
IF( C3.EQ.'TRD' ) THEN
NX = 32
END IF
ELSE IF( SNAME .AND. C2.EQ.'OR' ) THEN
IF( C3( 1: 1 ).EQ.'G' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NX = 128
END IF
END IF
ELSE IF( CNAME .AND. C2.EQ.'UN' ) THEN
IF( C3( 1: 1 ).EQ.'G' ) THEN
IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
THEN
NX = 128
END IF
END IF
END IF
ILAENV = NX
RETURN
!
80 CONTINUE
!
! ISPEC = 4: number of shifts (used by xHSEQR)
!
ILAENV = 6
RETURN
!
90 CONTINUE
!
! ISPEC = 5: minimum column dimension (not used)
!
ILAENV = 2
RETURN
!
100 CONTINUE
!
! ISPEC = 6: crossover point for SVD (used by xGELSS and xGESVD)
!
ILAENV = INT( REAL( MIN( N1, N2 ) )*1.6E0 )
RETURN
!
110 CONTINUE
!
! ISPEC = 7: number of processors (not used)
!
ILAENV = 1
RETURN
!
120 CONTINUE
!
! ISPEC = 8: crossover point for multishift (used by xHSEQR)
!
ILAENV = 50
RETURN
!
130 CONTINUE
!
! ISPEC = 9: maximum size of the subproblems at the bottom of the
! computation tree in the divide-and-conquer algorithm
! (used by xGELSD and xGESDD)
!
ILAENV = 25
RETURN
!
140 CONTINUE
!
! ISPEC = 10: ieee NaN arithmetic can be trusted not to trap
!
! ILAENV = 0
ILAENV = 1
IF( ILAENV.EQ.1 ) THEN
ILAENV = IEEECK
( 0, 0.0, 1.0 )
END IF
RETURN
!
150 CONTINUE
!
! ISPEC = 11: infinity arithmetic can be trusted not to trap
!
! ILAENV = 0
ILAENV = 1
IF( ILAENV.EQ.1 ) THEN
ILAENV = IEEECK( 1, 0.0, 1.0 )
END IF
RETURN
!
160 CONTINUE
!
! 12 <= ISPEC <= 16: xHSEQR or one of its subroutines.
!
ILAENV = IPARMQ( ISPEC, NAME, OPTS, N1, N2, N3, N4 )
RETURN
!
! End of ILAENV
!
END FUNCTION ILAENV