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 DLAQGE( M, N, A, LDA, R, C, ROWCND, COLCND, AMAX,
 36       $                   EQUED )
 37  *
 38  *  -- LAPACK auxiliary routine (version 3.2) --
 39  *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
 40  *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
 41  *     November 2006
 42  */
 43 
 44 #ifndef FLENS_LAPACK_EIG_LAQ_TCC
 45 #define FLENS_LAPACK_EIG_LAQ_TCC 1
 46 
 47 #include <flens/blas/blas.h>
 48 #include <flens/lapack/lapack.h>
 49 
 50 namespace flens { namespace lapack {
 51 
 52 //== generic lapack implementation =============================================
 53 template <typename MA, typename VR, typename VC,
 54           typename ROWCOND, typename COLCOND,
 55           typename AMAX>
 56 LAQ::Equilibration
 57 laq_generic(GeMatrix<MA>            &A,
 58             const DenseVector<VR>   &r,
 59             const DenseVector<VC>   &c,
 60             const ROWCOND           &rowCond,
 61             const COLCOND           &colCond,
 62             const AMAX              &amax)
 63 {
 64     using namespace LAQ;
 65 
 66     typedef typename GeMatrix<MA>::ElementType  T;
 67     typedef typename GeMatrix<MA>::IndexType    IndexType;
 68 
 69     const T One(1), Thresh(0.1);
 70 
 71     const Underscore<IndexType>  _;
 72 
 73     const IndexType m = A.numRows();
 74     const IndexType n = A.numCols();
 75 //
 76 //  Quick return if possible
 77 //
 78     if (m==0 || n==0) {
 79         return None;
 80     }
 81 //
 82 //  Initialize LARGE and SMALL.
 83 //
 84     const T small = lamch<T>(SafeMin) / lamch<T>(Precision);
 85     const T large = One / small;
 86 
 87     Equilibration  equed;
 88 
 89     if (rowCond>=Thresh && amax>=small && amax<=large) {
 90 //
 91 //  No row scaling
 92 //
 93         if (colCond>=Thresh) {
 94 //
 95 //          No column scaling
 96 //
 97             equed = None;
 98         } else {
 99 //
100 //          Column scaling
101 //
102             for (IndexType j=1; j<=n; ++j) {
103                 A(_,j) *= c(j);
104             }
105             equed = Column;
106         }
107     } else if (colCond>=Thresh) {
108 //
109 //      Row scaling, no column scaling
110 //
111         for (IndexType j=1; j<=n; ++j) {
112             for (IndexType i=1; i<=m; ++i) {
113                 A(i,j) *= r(i);
114             }
115         }
116         equed = Row;
117     } else {
118 //
119 //      Row and column scaling
120 //
121         for (IndexType j=1; j<=n; ++j) {
122             const T cj = c(j);
123             for (IndexType i=1; i<=m; ++i) {
124                 A(i,j) *= cj*r(i);
125             }
126         }
127         equed = Both;
128     }
129     return equed;
130 }
131 
132 
133 //== interface for native lapack ===============================================
134 
135 #ifdef CHECK_CXXLAPACK
136 
137 template <typename MA, typename VR, typename VC,
138           typename ROWCOND, typename COLCOND,
139           typename AMAX>
140 LAQ::Equilibration
141 laq_native(GeMatrix<MA>            &A,
142            const DenseVector<VR>   &r,
143            const DenseVector<VC>   &c,
144            const ROWCOND           &rowCond,
145            const COLCOND           &colCond,
146            const AMAX              &amax)
147 {
148     typedef typename GeMatrix<MA>::ElementType  T;
149 
150     const INTEGER  M = A.numRows();
151     const INTEGER  N = A.numCols();
152     const INTEGER  LDA = A.leadingDimension();
153     char           EQUED;
154 
155     if (IsSame<T,double>::value) {
156         LAPACK_IMPL(dlaqge)(&M,
157                             &N,
158                             A.data(),
159                             &LDA,
160                             r.data(),
161                             c.data(),
162                             &rowCond,
163                             &colCond,
164                             &amax,
165                             &EQUED);
166     } else {
167         ASSERT(0);
168     }
169 
170     if (EQUED=='B') {
171         return LAQ::Both;
172     } else if (EQUED=='R') {
173         return LAQ::Row;
174     } else if (EQUED=='C') {
175         return LAQ::Column;
176     }
177 
178     ASSERT(EQUED=='N');
179     return LAQ::None;
180 }
181 
182 #endif // CHECK_CXXLAPACK
183 
184 //== public interface ==========================================================
185 template <typename MA, typename VR, typename VC,
186           typename ROWCOND, typename COLCOND,
187           typename AMAX>
188 LAQ::Equilibration
189 laq(GeMatrix<MA>            &A,
190     const DenseVector<VR>   &r,
191     const DenseVector<VC>   &c,
192     const ROWCOND           &rowCond,
193     const COLCOND           &colCond,
194     const AMAX              &amax)
195 {
196     typedef typename GeMatrix<MA>::IndexType  IndexType;
197 //
198 //  Test the input parameters
199 //
200 #   ifndef NDEBUG
201     ASSERT(A.firstRow()==1);
202     ASSERT(A.firstCol()==1);
203 
204     const IndexType m = A.numRows();
205     const IndexType n = A.numCols();
206 
207     ASSERT(r.firstIndex()==1);
208     ASSERT(r.length()==m);
209 
210     ASSERT(c.firstIndex()==1);
211     ASSERT(c.length()==n);
212 #   endif
213 
214 #   ifdef CHECK_CXXLAPACK
215 //
216 //  Make copies of output arguments
217 //
218     typename GeMatrix<MA>::NoView  A_org  = A;
219 #   endif
220 
221 //
222 //  Call implementation
223 //
224     const auto equed = laq_generic(A, r, c, rowCond, colCond, amax);
225 
226 #   ifdef CHECK_CXXLAPACK
227 //
228 //  Make copies of results computed by the generic implementation
229 //
230     typename GeMatrix<MA>::NoView A_generic = A;
231 //
232 //  restore output arguments
233 //
234     A = A_org;
235 
236 //
237 //  Compare generic results with results from the native implementation
238 //
239     const auto equed_ = laq_native(A, r, c, rowCond, colCond, amax);
240 
241     bool failed = false;
242     if (! isIdentical(A_generic, A, "A_generic""A")) {
243         std::cerr << "CXXLAPACK: A_generic = "
244                   << A_generic << std::endl;
245         std::cerr << "F77LAPACK: A = " << A << std::endl;
246         failed = true;
247     }
248 
249     if (equed!=equed_) {
250         std::cerr << "CXXLAPACK: equed = " << equed << std::endl;
251         std::cerr << "F77LAPACK: equed_ = " << equed_ << std::endl;
252         failed = true;
253     }
254 
255     if (failed) {
256         ASSERT(0);
257     } else {
258 //        std::cerr << "passed: laq.tcc" << std::endl;
259     }
260 #   endif
261 
262     return equed;
263 }
264 
265 
266 //-- forwarding ----------------------------------------------------------------
267 template <typename MA, typename VR, typename VC,
268           typename ROWCOND, typename COLCOND,
269           typename AMAX>
270 LAQ::Equilibration
271 laq(MA             &&A,
272     const VR       &r,
273     const VC       &c,
274     const ROWCOND  &rowCond,
275     const COLCOND  &colCond,
276     const AMAX     &amax)
277 {
278     CHECKPOINT_ENTER;
279     const auto equed = laq(A, r, c, rowCond, colCond, amax);
280     CHECKPOINT_LEAVE;
281 
282     return equed;
283 }
284 
285 } } // namespace lapack, flens
286 
287 #endif // FLENS_LAPACK_EIG_LAQ_TCC