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/* slasdt.f -- translated by f2c (version 20061008).
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You must link the resulting object file with libf2c:
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on Microsoft Windows system, link with libf2c.lib;
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on Linux or Unix systems, link with .../path/to/libf2c.a -lm
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or, if you install libf2c.a in a standard place, with -lf2c -lm
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-- in that order, at the end of the command line, as in
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cc *.o -lf2c -lm
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
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http://www.netlib.org/f2c/libf2c.zip
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*/
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#include "clapack.h"
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/* Subroutine */ int slasdt_(integer *n, integer *lvl, integer *nd, integer *
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inode, integer *ndiml, integer *ndimr, integer *msub)
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{
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/* System generated locals */
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integer i__1, i__2;
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/* Builtin functions */
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double log(doublereal);
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/* Local variables */
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integer i__, il, ir, maxn;
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real temp;
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integer nlvl, llst, ncrnt;
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/* -- LAPACK auxiliary routine (version 3.2) -- */
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/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
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/* November 2006 */
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/* .. Scalar Arguments .. */
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/* .. */
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/* .. Array Arguments .. */
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/* .. */
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/* Purpose */
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/* ======= */
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/* SLASDT creates a tree of subproblems for bidiagonal divide and */
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/* conquer. */
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/* Arguments */
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/* ========= */
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/* N (input) INTEGER */
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/* On entry, the number of diagonal elements of the */
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/* bidiagonal matrix. */
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/* LVL (output) INTEGER */
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/* On exit, the number of levels on the computation tree. */
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/* ND (output) INTEGER */
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/* On exit, the number of nodes on the tree. */
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/* INODE (output) INTEGER array, dimension ( N ) */
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/* On exit, centers of subproblems. */
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/* NDIML (output) INTEGER array, dimension ( N ) */
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/* On exit, row dimensions of left children. */
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/* NDIMR (output) INTEGER array, dimension ( N ) */
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/* On exit, row dimensions of right children. */
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/* MSUB (input) INTEGER. */
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/* On entry, the maximum row dimension each subproblem at the */
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/* bottom of the tree can be of. */
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/* Further Details */
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/* =============== */
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/* Based on contributions by */
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/* Ming Gu and Huan Ren, Computer Science Division, University of */
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/* California at Berkeley, USA */
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/* ===================================================================== */
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/* .. Parameters .. */
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/* .. */
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/* .. Local Scalars .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. Executable Statements .. */
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/* Find the number of levels on the tree. */
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/* Parameter adjustments */
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--ndimr;
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--ndiml;
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--inode;
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/* Function Body */
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maxn = max(1,*n);
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temp = log((real) maxn / (real) (*msub + 1)) / log(2.f);
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*lvl = (integer) temp + 1;
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i__ = *n / 2;
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inode[1] = i__ + 1;
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ndiml[1] = i__;
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ndimr[1] = *n - i__ - 1;
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il = 0;
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ir = 1;
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llst = 1;
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i__1 = *lvl - 1;
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for (nlvl = 1; nlvl <= i__1; ++nlvl) {
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/* Constructing the tree at (NLVL+1)-st level. The number of */
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/* nodes created on this level is LLST * 2. */
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i__2 = llst - 1;
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for (i__ = 0; i__ <= i__2; ++i__) {
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il += 2;
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ir += 2;
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ncrnt = llst + i__;
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ndiml[il] = ndiml[ncrnt] / 2;
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ndimr[il] = ndiml[ncrnt] - ndiml[il] - 1;
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inode[il] = inode[ncrnt] - ndimr[il] - 1;
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ndiml[ir] = ndimr[ncrnt] / 2;
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ndimr[ir] = ndimr[ncrnt] - ndiml[ir] - 1;
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inode[ir] = inode[ncrnt] + ndiml[ir] + 1;
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/* L10: */
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}
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llst <<= 1;
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/* L20: */
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}
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*nd = (llst << 1) - 1;
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return 0;
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/* End of SLASDT */
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} /* slasdt_ */
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