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/* ilaenv.f -- translated by f2c (version 20061008).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "clapack.h"
#include "string.h"
/* Table of constant values */
static integer c__1 = 1;
static real c_b163 = 0.f;
static real c_b164 = 1.f;
static integer c__0 = 0;
integer ilaenv_(integer *ispec, char *name__, char *opts, integer *n1,
integer *n2, integer *n3, integer *n4)
{
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* January 2007 */
/* .. Scalar Arguments .. */
/* .. */
/* 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 .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. Executable Statements .. */
switch (*ispec) {
case 1:
/* 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. */
return 1;
case 2:
/* ISPEC = 2: minimum block size */
return 2;
case 3:
/* ISPEC = 3: crossover point */
return 3;
case 4:
/* ISPEC = 4: number of shifts (used by xHSEQR) */
return 6;
case 5:
/* ISPEC = 5: minimum column dimension (not used) */
return 2;
case 6:
/* ISPEC = 6: crossover point for SVD (used by xGELSS and xGESVD) */
return (integer) ((real) min(*n1,*n2) * 1.6f);
case 7:
/* ISPEC = 7: number of processors (not used) */
return 1;
case 8:
/* ISPEC = 8: crossover point for multishift (used by xHSEQR) */
return 50;
case 9:
/* 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) */
return 25;
case 10:
/* ISPEC = 10: ieee NaN arithmetic can be trusted not to trap */
return ieeeck_(&c__1, &c_b163, &c_b164);
case 11:
/* ISPEC = 11: infinity arithmetic can be trusted not to trap */
return ieeeck_(&c__0, &c_b163, &c_b164);
case 12:
case 13:
case 14:
case 15:
case 16:
/* 12 <= ISPEC <= 16: xHSEQR or one of its subroutines. */
return iparmq_(ispec, name__, opts, n1, n2, n3, n4);
default:
break;
}
/* Invalid value for ISPEC */
return -1;
/* End of ILAENV */
} /* ilaenv_ */