xlaenv.c

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/* xlaenv.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 "f2c.h"
#include "blaswrap.h"

/* Common Block Declarations */

struct {
    integer iparms[100];
} claenv_;

#define claenv_1 claenv_

/* Subroutine */ int xlaenv_(integer *ispec, integer *nvalue)
{

/*  -- LAPACK auxiliary routine (version 3.1) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  XLAENV sets certain machine- and problem-dependent quantities */
/*  which will later be retrieved by ILAENV. */

/*  Arguments */
/*  ========= */

/*  ISPEC   (input) INTEGER */
/*          Specifies the parameter to be set in the COMMON array IPARMS. */
/*          = 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: another 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 */
/*          12 <= ISPEC <= 16: */
/*               xHSEQR or one of its subroutines, */
/*               see IPARMQ for detailed explanation */

/*  NVALUE  (input) INTEGER */
/*          The value of the parameter specified by ISPEC. */

/*  ===================================================================== */

/*     .. Arrays in Common .. */
/*     .. */
/*     .. Common blocks .. */
/*     .. */
/*     .. Save statement .. */
/*     .. */
/*     .. Executable Statements .. */

    if (*ispec >= 1 && *ispec <= 16) {
        claenv_1.iparms[*ispec - 1] = *nvalue;
    }

    return 0;

/*     End of XLAENV */

} /* xlaenv_ */