src/gromacs/simd/tests/base.h

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
   3  *
   4  * Copyright (c) 2014,2015,2018, by the GROMACS development team, led by
   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
   6  * and including many others, as listed in the AUTHORS file in the
   7  * top-level source directory and at http://www.gromacs.org.
   8  *
   9  * GROMACS is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 2.1
  12  * of the License, or (at your option) any later version.
  13  *
  14  * GROMACS is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with GROMACS; if not, see
  21  * http://www.gnu.org/licenses, or write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
  23  *
  24  * If you want to redistribute modifications to GROMACS, please
  25  * consider that scientific software is very special. Version
  26  * control is crucial - bugs must be traceable. We will be happy to
  27  * consider code for inclusion in the official distribution, but
  28  * derived work must not be called official GROMACS. Details are found
  29  * in the README & COPYING files - if they are missing, get the
  30  * official version at http://www.gromacs.org.
  31  *
  32  * To help us fund GROMACS development, we humbly ask that you cite
  33  * the research papers on the package. Check out http://www.gromacs.org.
  34  */
  35
  36 #ifndef GMX_SIMD_TESTS_BASE_H
  37 #define GMX_SIMD_TESTS_BASE_H
  38
  39 /*! \internal \file
  40  * \brief
  41  * Declares common base class for testing SIMD and SIMD4.
  42  *
  43  * The base class contains the settings for absolute and ulp tolerances,
  44  * as well as testing ranges used for both SIMD and SIMD4 tests, mainly
  45  * to keep everything symmetric and clean. The class also defines a couple
  46  * of generic tests that compare vectors of elements with arbitrary length for
  47  * either exact or approximate matching (in terms of ulp). These are used in
  48  * derived classes that convert either SIMD or SIMD4 values to
  49  * std::vector<real> and then performs the comparison.
  50  *
  51  * \author Erik Lindahl <erik.lindahl@scilifelab.se>
  52  * \ingroup module_simd
  53  */
  54 #include "config.h"
  55
  56 #include <cstdint>
  57
  58 #include <vector>
  59
  60 #include <gtest/gtest.h>
  61
  62 #include "gromacs/utility/basedefinitions.h"
  63 #include "gromacs/utility/real.h"
  64
  65 namespace gmx
  66 {
  67 namespace test
  68 {
  69
  70 /*! \internal
  71  * \brief
  72  * Base class for SIMD test fixtures.
  73  *
  74  * This class contains settings that are common for SIMD and SIMD4 tests,
  75  * and it is thus not used directly for any tests, but derived separately
  76  * in simd.h and simd4.h.
  77  *
  78  * \ingroup module_simd
  79  */
  80 class SimdBaseTest : public ::testing::Test
  81 {
  82     public:
  83         /*! \brief Initialize new SIMD test fixture with default tolerances.
  84          *
  85          * The default absolute tolerance is set to 0, which means the we always
  86          * check the ulp tolerance by default (passing the absolute tolerance
  87          * test would otherwise mean we approve the test instantly).
  88          *
  89          * The default ulp tolerance is set based on the target number of
  90          * bits requested for single or double precision, depending on what
  91          * the default Gromacs precision is. We add two bits to avoid
  92          * tests failing due to corner cases where compiler optimization might
  93          * cause a slight precision loss e.g. for very small numbers.
  94          *
  95          * Most SIMD math functions actually achieve 2-3 ulp accuracy in single,
  96          * but by being a bit liberal we only catch real errors rather than
  97          * doing compiler-standard-compliance debugging.
  98          *
  99          * The range is used by derived classes to test math functions. The
 100          * default test range will be [1,10], which is intentionally
 101          * conservative so it works with (inverse) square root, division,
 102          * exponentials, logarithms, and error functions.
 103          */
 104         SimdBaseTest() :
 105 #if GMX_DOUBLE
 106             ulpTol_((1LL << (2 + std::numeric_limits<double>::digits-GMX_SIMD_ACCURACY_BITS_DOUBLE))),
 107 #else
 108             ulpTol_((1LL << (2 + std::numeric_limits<float>::digits-GMX_SIMD_ACCURACY_BITS_SINGLE))),
 109 #endif
 110             absTol_(0), range_(std::pair<real, real>(1, 10))
 111         {
 112         }
 113
 114         /*! \brief Adjust ulp tolerance from the default 10 (float) or 255 (double). */
 115         void setUlpTol(std::int64_t newTol)   { ulpTol_ = newTol; }
 116
 117         /*! \brief Adjust ulp tolerance for single accuracy functions. */
 118         void setUlpTolSingleAccuracy(std::int64_t newTol)
 119         {
 120 #if GMX_DOUBLE
 121             setUlpTol(newTol * (1LL << (std::numeric_limits<real>::digits-std::numeric_limits<float>::digits)));
 122 #else
 123             setUlpTol(newTol);
 124 #endif
 125         }
 126
 127         /*! \brief Adjust the absolute tolerance from the default 0.
 128          *
 129          * If values are closer than the absolute tolerance, the test will pass
 130          * no matter what their ulp difference is.
 131          */
 132         void setAbsTol(real newTol)          { absTol_ = newTol; }
 133
 134         /*! \brief Change math function testing range from the default [1,10]. */
 135         void setRange(real low, real high) { range_.first = low; range_.second = high; }
 136
 137         static int  s_nPoints;    //!< Number of test points to use, settable on command line.
 138
 139         /*! \brief Compare two std::vector<real> for approximate equality.
 140          *
 141          * This is an internal implementation routine that will be used by
 142          * routines in derived child classes that first convert SIMD or SIMD4
 143          * variables to std::vector<real>. Do not call it directly.
 144          *
 145          * This routine is designed according to the Google test specs, so the char
 146          * strings will describe the arguments to the macro.
 147          *
 148          * The comparison is applied to each element, and it returns true if each element
 149          * in the vector test variable is within the class tolerances of the corresponding
 150          * reference elements.
 151          */
 152         ::testing::AssertionResult
 153         compareVectorRealUlp(const char * refExpr,  const char * tstExpr,
 154                              const std::vector<real> &ref, const std::vector<real> &tst);
 155
 156         /*! \brief Compare std::vectors for exact equality.
 157          *
 158          * The template in this class makes it usable for testing both
 159          * SIMD floating-point and integers variables, after conversion to
 160          * vectors.
 161          * This is an internal implementation routine that will be used by
 162          * routines in derived child classes that first convert SIMD or SIMD4
 163          * variables to std::vector<real>. Do not call it directly.
 164          *
 165          * This routine is designed according to the Google test specs, so the char
 166          * strings will describe the arguments to the macro.
 167          *
 168          * The comparison is applied to each element, and it returns true if each element
 169          * in the vector test variable is within the class tolerances of the corresponding
 170          * reference elements.
 171          */
 172         template <typename T> ::testing::AssertionResult
 173         compareVectorEq(const char * refExpr,  const char * tstExpr,
 174                         const std::vector<T> &ref, const std::vector<T> &tst)
 175         {
 176             if (ref == tst)
 177             {
 178                 return ::testing::AssertionSuccess();
 179             }
 180             else
 181             {
 182                 return ::testing::AssertionFailure()
 183                        << "Failing SIMD comparison between " << refExpr << " and " << tstExpr << std::endl
 184                        << "Ref. values: " << ::testing::PrintToString(ref) << std::endl
 185                        << "Test values: " << ::testing::PrintToString(tst) << std::endl;
 186             }
 187         }
 188
 189     protected:
 190         std::int64_t           ulpTol_;       //!< Current tolerance in units-in-last-position.
 191         real                   absTol_;       //!< Current absolute tolerance.
 192         std::pair<real, real>  range_;        //!< Range for math function tests.
 193 };
 194
 195 }      // namespace test
 196 }      // namespace gmx
 197
 198 #endif // GMX_SIMD_TESTS_BASE_H