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/*
* Copyright (c) 2011, Michael Lehn * * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1) Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2) Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3) Neither the name of the FLENS development group nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* Based on * SUBROUTINE DLASSQ( N, X, INCX, SCALE, SUMSQ ) * * -- LAPACK auxiliary routine (version 3.2) -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- * November 2006 */ #ifndef FLENS_LAPACK_LA_LASSQ_TCC #define FLENS_LAPACK_LA_LASSQ_TCC 1 #include <cmath> #include <flens/blas/blas.h> #include <flens/lapack/lapack.h> namespace flens { namespace lapack { //== generic lapack implementation ============================================= namespace generic { template <typename VX, typename T> void lassq_impl(const DenseVector<VX> &x, T &scale, T &sumsq) { using std::abs; using flens::pow; typedef typename DenseVector<VX>::IndexType IndexType; const IndexType n = x.length(); if (n>0) { for (IndexType i=1; i<=n; ++i) { if (x(i)!=T(0)) { const T absXi = abs(x(i)); if (scale<absXi) { sumsq = 1 + sumsq*pow(scale/absXi, 2); scale = absXi; } else { sumsq += pow(absXi/scale, 2); } } } } } } // namespace generic //== interface for native lapack =============================================== #ifdef USE_CXXLAPACK namespace external { template <typename VX, typename T> void lassq_impl(const DenseVector<VX> &x, T &scale, T &sumsq) { cxxlapack::lassq(x.length(), x.data(), x.stride(), scale, sumsq); } } // namespace external #endif // USE_CXXLAPACK //== public interface ========================================================== template <typename VX, typename T> void lassq(const DenseVector<VX> &x, T &scale, T &sumsq) { LAPACK_DEBUG_OUT("lassq"); // // Test the input parameters // ASSERT(x.inc()>0); // // Make copies of output arguments // # ifdef CHECK_CXXLAPACK T _scale = scale; T _sumsq = sumsq; # endif // // Call implementation // LAPACK_SELECT::lassq_impl(x, scale, sumsq); # ifdef CHECK_CXXLAPACK // // Compare results // external::lassq_impl(x, _scale, _sumsq); bool failed = false; if (! isIdentical(scale, _scale, " scale", "_scale")) { std::cerr << "CXXLAPACK: scale = " << scale << std::endl; std::cerr << "F77LAPACK: _scale = " << _scale << std::endl; failed = true; } if (! isIdentical(sumsq, _sumsq, " sumsq", "_sumsq")) { std::cerr << "CXXLAPACK: sumsq = " << sumsq << std::endl; std::cerr << "F77LAPACK: _sumsq = " << _sumsq << std::endl; failed = true; } if (failed) { ASSERT(0); } else { // std::cerr << "passed: lassq.tcc" << std::endl; } # endif } } } // namespace lapack, flens #endif // FLENS_LAPACK_LA_LASSQ_TCC |