1 /*
  2  *   Copyright (c) 2011, Michael Lehn
  3  *
  4  *   All rights reserved.
  5  *
  6  *   Redistribution and use in source and binary forms, with or without
  7  *   modification, are permitted provided that the following conditions
  8  *   are met:
  9  *
 10  *   1) Redistributions of source code must retain the above copyright
 11  *      notice, this list of conditions and the following disclaimer.
 12  *   2) Redistributions in binary form must reproduce the above copyright
 13  *      notice, this list of conditions and the following disclaimer in
 14  *      the documentation and/or other materials provided with the
 15  *      distribution.
 16  *   3) Neither the name of the FLENS development group nor the names of
 17  *      its contributors may be used to endorse or promote products derived
 18  *      from this software without specific prior written permission.
 19  *
 20  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 21  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 22  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 23  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 24  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 25  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 26  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 27  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 28  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 29  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 30  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 31  */
 32 
 33 /* Based on
 34  *
 35       SUBROUTINE DHSEQR( JOB, COMPZ, N, ILO, IHI, H, LDH, WR, WI, Z,
 36      $                   LDZ, WORK, LWORK, INFO )
 37  *
 38  *  -- LAPACK computational routine (version 3.2.2) --
 39  *     Univ. of Tennessee, Univ. of California Berkeley,
 40  *     Univ. of Colorado Denver and NAG Ltd..
 41  *     June 2010
 42  */
 43 
 44 #ifndef FLENS_LAPACK_EIG_HSEQR_H
 45 #define FLENS_LAPACK_EIG_HSEQR_H 1
 46 
 47 #include <flens/matrixtypes/matrixtypes.h>
 48 #include <flens/vectortypes/vectortypes.h>
 49 
 50 namespace flens { namespace lapack {
 51 
 52 namespace HSEQR {
 53 
 54     enum Job {
 55         Eigenvalues,    // compute eigenvalues only
 56         Schur           // compute eigenvalues and the Schur form T
 57     };
 58 
 59     enum ComputeZ {
 60         No,             // no Schur vectors are computed;
 61         Init,           // Z is initialized to the unit matrix and the matrix Z
 62                         // of Schur vectors of H is returned;
 63         NoInit,         // Z must contain an orthogonal matrix Q on entry, and
 64                         // the product Q*Z is returned.
 65     };
 66 
 67 }
 68 
 69 //== hseqr_wsq (worksize query) ================================================
 70 template <typename IndexType, typename MH>
 71     IndexType
 72     hseqr_wsq(HSEQR::Job            job,
 73               HSEQR::ComputeZ       computeZ,
 74               IndexType             iLo,
 75               IndexType             iHi,
 76               const GeMatrix<MH>    &H);
 77 
 78 //== hseqr =====================================================================
 79 template <typename IndexType, typename MH, typename VWR, typename VWI,
 80           typename MZ, typename VWORK>
 81     IndexType
 82     hseqr(HSEQR::Job                job,
 83           HSEQR::ComputeZ           compZ,
 84           IndexType                 iLo,
 85           IndexType                 iHi,
 86           GeMatrix<MH>              &H,
 87           DenseVector<VWR>          &wr,
 88           DenseVector<VWI>          &wi,
 89           GeMatrix<MZ>              &Z,
 90           DenseVector<VWORK>        &work);
 91 
 92 
 93 //-- forwarding ----------------------------------------------------------------
 94 template <typename IndexType, typename MH>
 95     IndexType
 96     hseqr_wsq(HSEQR::Job        job,
 97               HSEQR::ComputeZ   computeZ,
 98               IndexType         iLo,
 99               IndexType         iHi,
100               const MH          &&H);
101 
102 template <typename IndexType, typename MH, typename VWR, typename VWI,
103           typename MZ, typename VWORK>
104     IndexType
105     hseqr(HSEQR::Job            job,
106           HSEQR::ComputeZ       compZ,
107           IndexType             iLo,
108           IndexType             iHi,
109           MH                    &&H,
110           VWR                   &&wr,
111           VWI                   &&wi,
112           MZ                    &&Z,
113           VWORK                 &&work);
114 
115 } } // namespace lapack, flens
116 
117 #endif // FLENS_LAPACK_EIG_HSEQR_H