src/gromacs/simd/tests/base.h

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  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 the absolute tolerance from the default 0.
 118          *
 119          * If values are closer than the absolute tolerance, the test will pass
 120          * no matter what their ulp difference is.
 121          */
 122         void setAbsTol(real newTol)          { absTol_ = newTol; }
 123
 124         /*! \brief Change math function testing range from the default [1,10]. */
 125         void setRange(real low, real high) { range_.first = low; range_.second = high; }
 126
 127         static int  s_nPoints;    //!< Number of test points to use, settable on command line.
 128
 129         /*! \brief Compare two std::vector<real> for approximate equality.
 130          *
 131          * This is an internal implementation routine that will be used by
 132          * routines in derived child classes that first convert SIMD or SIMD4
 133          * variables to std::vector<real>. Do not call it directly.
 134          *
 135          * This routine is designed according to the Google test specs, so the char
 136          * strings will describe the arguments to the macro.
 137          *
 138          * The comparison is applied to each element, and it returns true if each element
 139          * in the vector test variable is within the class tolerances of the corresponding
 140          * reference elements.
 141          */
 142         ::testing::AssertionResult
 143         compareVectorRealUlp(const char * refExpr,  const char * tstExpr,
 144                              const std::vector<real> &ref, const std::vector<real> &tst);
 145
 146         /*! \brief Compare std::vectors for exact equality.
 147          *
 148          * The template in this class makes it usable for testing both
 149          * SIMD floating-point and integers variables, after conversion to
 150          * vectors.
 151          * This is an internal implementation routine that will be used by
 152          * routines in derived child classes that first convert SIMD or SIMD4
 153          * variables to std::vector<real>. Do not call it directly.
 154          *
 155          * This routine is designed according to the Google test specs, so the char
 156          * strings will describe the arguments to the macro.
 157          *
 158          * The comparison is applied to each element, and it returns true if each element
 159          * in the vector test variable is within the class tolerances of the corresponding
 160          * reference elements.
 161          */
 162         template <typename T> ::testing::AssertionResult
 163         compareVectorEq(const char * refExpr,  const char * tstExpr,
 164                         const std::vector<T> &ref, const std::vector<T> &tst)
 165         {
 166             if (ref == tst)
 167             {
 168                 return ::testing::AssertionSuccess();
 169             }
 170             else
 171             {
 172                 return ::testing::AssertionFailure()
 173                        << "Failing SIMD comparison between " << refExpr << " and " << tstExpr << std::endl
 174                        << "Ref. values: " << ::testing::PrintToString(ref) << std::endl
 175                        << "Test values: " << ::testing::PrintToString(tst) << std::endl;
 176             }
 177         }
 178
 179     protected:
 180         std::int64_t           ulpTol_;       //!< Current tolerance in units-in-last-position.
 181         real                   absTol_;       //!< Current absolute tolerance.
 182         std::pair<real, real>  range_;        //!< Range for math function tests.
 183 };
 184
 185 }      // namespace
 186 }      // namespace
 187
 188 #endif // GMX_SIMD_TESTS_BASE_H