#include "blaswrap.h"
/* -- translated by f2c (version 19990503).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
/* Common Block Declarations */
struct {
integer iparms[100];
} claenv_;
#define claenv_1 claenv_
/* Table of constant values */
static integer c__0 = 0;
static real c_b3 = 0.f;
static real c_b4 = 1.f;
static integer c__1 = 1;
integer ilaenv_(integer *ispec, char *name__, char *opts, integer *n1,
integer *n2, integer *n3, integer *n4, ftnlen name_len, ftnlen
opts_len)
{
/* System generated locals */
integer ret_val;
/* Local variables */
extern integer ieeeck_(integer *, real *, real *);
/* -- LAPACK auxiliary routine (version 3.0) --
Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
Courant Institute, Argonne National Lab, and Rice University
June 30, 1999
Purpose
=======
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.
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
=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.
NAME (input) CHARACTER*(*)
The name of the calling subroutine.
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.
(ILAENV) (output) INTEGER
>= 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, 'STRTRI', UPLO // DIAG, N, -1, -1, -1 )
IF( NB.LE.1 ) NB = MAX( 1, N )
===================================================================== */
if (*ispec >= 1 && *ispec <= 5) {
/* Return a value from the common block. */
ret_val = claenv_1.iparms[*ispec - 1];
} else if (*ispec == 6) {
/* Compute SVD crossover point. */
ret_val = (integer) ((real) min(*n1,*n2) * 1.6f);
} else if (*ispec >= 7 && *ispec <= 9) {
/* Return a value from the common block. */
ret_val = claenv_1.iparms[*ispec - 1];
} else if (*ispec == 10) {
/* IEEE NaN arithmetic can be trusted not to trap
ILAENV = 0 */
ret_val = 1;
if (ret_val == 1) {
ret_val = ieeeck_(&c__0, &c_b3, &c_b4);
}
} else if (*ispec == 11) {
/* Infinity arithmetic can be trusted not to trap
ILAENV = 0 */
ret_val = 1;
if (ret_val == 1) {
ret_val = ieeeck_(&c__1, &c_b3, &c_b4);
}
} else {
/* Invalid value for ISPEC */
ret_val = -1;
}
return ret_val;
/* End of ILAENV */
} /* ilaenv_ */