Return to dlasdt.f CVS log

Up to [local] / rpl / lapack / lapack

Annotation of rpl/lapack/lapack/dlasdt.f, revision 1.9

1.9     ! bertrand    1: *> \brief \b DLASDT
        !             2: *
        !             3: *  =========== DOCUMENTATION ===========
        !             4: *
        !             5: * Online html documentation available at 
        !             6: *            http://www.netlib.org/lapack/explore-html/ 
        !             7: *
        !             8: *> \htmlonly
        !             9: *> Download DLASDT + dependencies 
        !            10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlasdt.f"> 
        !            11: *> [TGZ]</a> 
        !            12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlasdt.f"> 
        !            13: *> [ZIP]</a> 
        !            14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlasdt.f"> 
        !            15: *> [TXT]</a>
        !            16: *> \endhtmlonly 
        !            17: *
        !            18: *  Definition:
        !            19: *  ===========
        !            20: *
        !            21: *       SUBROUTINE DLASDT( N, LVL, ND, INODE, NDIML, NDIMR, MSUB )
        !            22: * 
        !            23: *       .. Scalar Arguments ..
        !            24: *       INTEGER            LVL, MSUB, N, ND
        !            25: *       ..
        !            26: *       .. Array Arguments ..
        !            27: *       INTEGER            INODE( * ), NDIML( * ), NDIMR( * )
        !            28: *       ..
        !            29: *  
        !            30: *
        !            31: *> \par Purpose:
        !            32: *  =============
        !            33: *>
        !            34: *> \verbatim
        !            35: *>
        !            36: *> DLASDT creates a tree of subproblems for bidiagonal divide and
        !            37: *> conquer.
        !            38: *> \endverbatim
        !            39: *
        !            40: *  Arguments:
        !            41: *  ==========
        !            42: *
        !            43: *> \param[in] N
        !            44: *> \verbatim
        !            45: *>          N is INTEGER
        !            46: *>          On entry, the number of diagonal elements of the
        !            47: *>          bidiagonal matrix.
        !            48: *> \endverbatim
        !            49: *>
        !            50: *> \param[out] LVL
        !            51: *> \verbatim
        !            52: *>          LVL is INTEGER
        !            53: *>          On exit, the number of levels on the computation tree.
        !            54: *> \endverbatim
        !            55: *>
        !            56: *> \param[out] ND
        !            57: *> \verbatim
        !            58: *>          ND is INTEGER
        !            59: *>          On exit, the number of nodes on the tree.
        !            60: *> \endverbatim
        !            61: *>
        !            62: *> \param[out] INODE
        !            63: *> \verbatim
        !            64: *>          INODE is INTEGER array, dimension ( N )
        !            65: *>          On exit, centers of subproblems.
        !            66: *> \endverbatim
        !            67: *>
        !            68: *> \param[out] NDIML
        !            69: *> \verbatim
        !            70: *>          NDIML is INTEGER array, dimension ( N )
        !            71: *>          On exit, row dimensions of left children.
        !            72: *> \endverbatim
        !            73: *>
        !            74: *> \param[out] NDIMR
        !            75: *> \verbatim
        !            76: *>          NDIMR is INTEGER array, dimension ( N )
        !            77: *>          On exit, row dimensions of right children.
        !            78: *> \endverbatim
        !            79: *>
        !            80: *> \param[in] MSUB
        !            81: *> \verbatim
        !            82: *>          MSUB is INTEGER
        !            83: *>          On entry, the maximum row dimension each subproblem at the
        !            84: *>          bottom of the tree can be of.
        !            85: *> \endverbatim
        !            86: *
        !            87: *  Authors:
        !            88: *  ========
        !            89: *
        !            90: *> \author Univ. of Tennessee 
        !            91: *> \author Univ. of California Berkeley 
        !            92: *> \author Univ. of Colorado Denver 
        !            93: *> \author NAG Ltd. 
        !            94: *
        !            95: *> \date November 2011
        !            96: *
        !            97: *> \ingroup auxOTHERauxiliary
        !            98: *
        !            99: *> \par Contributors:
        !           100: *  ==================
        !           101: *>
        !           102: *>     Ming Gu and Huan Ren, Computer Science Division, University of
        !           103: *>     California at Berkeley, USA
        !           104: *>
        !           105: *  =====================================================================
1.1       bertrand  106:       SUBROUTINE DLASDT( N, LVL, ND, INODE, NDIML, NDIMR, MSUB )
                    107: *
1.9     ! bertrand  108: *  -- LAPACK auxiliary routine (version 3.4.0) --
1.1       bertrand  109: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
                    110: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.9     ! bertrand  111: *     November 2011
1.1       bertrand  112: *
                    113: *     .. Scalar Arguments ..
                    114:       INTEGER            LVL, MSUB, N, ND
                    115: *     ..
                    116: *     .. Array Arguments ..
                    117:       INTEGER            INODE( * ), NDIML( * ), NDIMR( * )
                    118: *     ..
                    119: *
                    120: *  =====================================================================
                    121: *
                    122: *     .. Parameters ..
                    123:       DOUBLE PRECISION   TWO
                    124:       PARAMETER          ( TWO = 2.0D+0 )
                    125: *     ..
                    126: *     .. Local Scalars ..
                    127:       INTEGER            I, IL, IR, LLST, MAXN, NCRNT, NLVL
                    128:       DOUBLE PRECISION   TEMP
                    129: *     ..
                    130: *     .. Intrinsic Functions ..
                    131:       INTRINSIC          DBLE, INT, LOG, MAX
                    132: *     ..
                    133: *     .. Executable Statements ..
                    134: *
                    135: *     Find the number of levels on the tree.
                    136: *
                    137:       MAXN = MAX( 1, N )
                    138:       TEMP = LOG( DBLE( MAXN ) / DBLE( MSUB+1 ) ) / LOG( TWO )
                    139:       LVL = INT( TEMP ) + 1
                    140: *
                    141:       I = N / 2
                    142:       INODE( 1 ) = I + 1
                    143:       NDIML( 1 ) = I
                    144:       NDIMR( 1 ) = N - I - 1
                    145:       IL = 0
                    146:       IR = 1
                    147:       LLST = 1
                    148:       DO 20 NLVL = 1, LVL - 1
                    149: *
                    150: *        Constructing the tree at (NLVL+1)-st level. The number of
                    151: *        nodes created on this level is LLST * 2.
                    152: *
                    153:          DO 10 I = 0, LLST - 1
                    154:             IL = IL + 2
                    155:             IR = IR + 2
                    156:             NCRNT = LLST + I
                    157:             NDIML( IL ) = NDIML( NCRNT ) / 2
                    158:             NDIMR( IL ) = NDIML( NCRNT ) - NDIML( IL ) - 1
                    159:             INODE( IL ) = INODE( NCRNT ) - NDIMR( IL ) - 1
                    160:             NDIML( IR ) = NDIMR( NCRNT ) / 2
                    161:             NDIMR( IR ) = NDIMR( NCRNT ) - NDIML( IR ) - 1
                    162:             INODE( IR ) = INODE( NCRNT ) + NDIML( IR ) + 1
                    163:    10    CONTINUE
                    164:          LLST = LLST*2
                    165:    20 CONTINUE
                    166:       ND = LLST*2 - 1
                    167: *
                    168:       RETURN
                    169: *
                    170: *     End of DLASDT
                    171: *
                    172:       END