.TH "TESTING/LIN/ilaenv.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*-
.ad l
.nh
.SH NAME
TESTING/LIN/ilaenv.f
.SH SYNOPSIS
.br
.PP
.SS "Functions/Subroutines"

.in +1c
.ti -1c
.RI "integer function \fBilaenv\fP (ispec, name, opts, n1, n2, n3, n4)"
.br
.RI "\fBILAENV\fP "
.ti -1c
.RI "integer function \fBilaenv2stage\fP (ispec, name, opts, n1, n2, n3, n4)"
.br
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "integer function ilaenv (integer ispec, character*( * ) name, character*( * ) opts, integer n1, integer n2, integer n3, integer n4)"

.PP
\fBILAENV\fP 
.PP
\fBPurpose:\fP
.RS 4

.PP
.nf
 ILAENV returns problem-dependent parameters for the local
 environment\&.  See ISPEC for a description of the parameters\&.

 In this version, the problem-dependent parameters are contained in
 the integer array IPARMS in the common block CLAENV and the value
 with index ISPEC is copied to ILAENV\&.  This version of ILAENV is
 to be used in conjunction with XLAENV in TESTING and TIMING\&.
.fi
.PP
 
.RE
.PP
\fBParameters\fP
.RS 4
\fIISPEC\fP 
.PP
.nf
          ISPEC is 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
          =10: ieee NaN arithmetic can be trusted not to trap
          =11: infinity arithmetic can be trusted not to trap

          Other specifications (up to 100) can be added later\&.
.fi
.PP
.br
\fINAME\fP 
.PP
.nf
          NAME is CHARACTER*(*)
          The name of the calling subroutine\&.
.fi
.PP
.br
\fIOPTS\fP 
.PP
.nf
          OPTS is 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'\&.
.fi
.PP
.br
\fIN1\fP 
.PP
.nf
          N1 is INTEGER
.fi
.PP
.br
\fIN2\fP 
.PP
.nf
          N2 is INTEGER
.fi
.PP
.br
\fIN3\fP 
.PP
.nf
          N3 is INTEGER
.fi
.PP
.br
\fIN4\fP 
.PP
.nf
          N4 is INTEGER

          Problem dimensions for the subroutine NAME; these may not all
          be required\&.
.fi
.PP
.RE
.PP
\fBReturns\fP
.RS 4
ILAENV 
.PP
.nf
          ILAENV is INTEGER
          >= 0: the value of the parameter specified by ISPEC
          < 0:  if ILAENV = -k, the k-th argument had an illegal value\&.
.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
\fBFurther Details:\fP
.RS 4

.PP
.nf
  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 )
.fi
.PP
 
.RE
.PP

.PP
Definition at line \fB148\fP of file \fBilaenv\&.f\fP\&.
.SS "integer function ilaenv2stage (integer ispec, character*( * ) name, character*( * ) opts, integer n1, integer n2, integer n3, integer n4)"

.PP
Definition at line \fB244\fP of file \fBilaenv\&.f\fP\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for LAPACK from the source code\&.