src/gromacs/simd/tests/simd4_math.cpp

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
   3  *
   4  * Copyright (c) 2014,2015, 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 #include "gmxpre.h"
  36
  37 #include "config.h"
  38
  39 #include <cstdint>
  40
  41 #include <vector>
  42
  43 #include "gromacs/math/utilities.h"
  44 #include "gromacs/options/basicoptions.h"
  45 #include "gromacs/simd/simd.h"
  46 #include "gromacs/simd/simd_math.h"
  47
  48 #include "simd4.h"
  49
  50 #if GMX_SIMD
  51
  52 namespace gmx
  53 {
  54 namespace test
  55 {
  56
  57 /*! \cond internal */
  58 /*! \addtogroup module_simd */
  59 /*! \{ */
  60
  61 #if GMX_SIMD4_HAVE_REAL
  62
  63 class Simd4MathTest : public Simd4Test
  64 {
  65     public:
  66         ::testing::AssertionResult
  67                              compareSimd4MathFunction(const char * refFuncExpr, const char *simd4FuncExpr,
  68                                                       real refFunc(real x),     Simd4Real gmx_simdcall simd4Func(Simd4Real x));
  69 };
  70
  71 /*! \brief Test approximate equality of SIMD4 vs reference version of a function.
  72  *
  73  * This macro takes vanilla C and SIMD flavors of a function and tests it with
  74  * the number of points, range, and tolerances specified by the test fixture class.
  75  */
  76 #define GMX_EXPECT_SIMD4_FUNC_NEAR(refFunc, tstFunc) \
  77     EXPECT_PRED_FORMAT2(compareSimd4MathFunction, refFunc, tstFunc)
  78
  79
  80 /*! \brief Implementation routine to compare SIMD4 vs reference functions.
  81  *
  82  * \param refFuncExpr    Description of reference function expression
  83  * \param simd4FuncExpr  Description of SIMD function expression
  84  * \param refFunc        Reference math function pointer
  85  * \param simd4Func      SIMD math function pointer
  86  *
  87  * The function will be tested with the range and tolerances specified in
  88  * the SimdBaseTest class. You should not never call this function directly,
  89  * but use the macro GMX_EXPECT_SIMD4_FUNC_NEAR(refFunc,tstFunc) instead.
  90  */
  91 ::testing::AssertionResult
  92 Simd4MathTest::compareSimd4MathFunction(const char * refFuncExpr, const char *simd4FuncExpr,
  93                                         real refFunc(real x),     Simd4Real gmx_simdcall simd4Func(Simd4Real x))
  94 {
  95     std::vector<real>            vx(GMX_SIMD4_WIDTH);
  96     std::vector<real>            vref(GMX_SIMD4_WIDTH);
  97     std::vector<real>            vtst(GMX_SIMD4_WIDTH);
  98     real                         dx;
  99     std::int64_t                 ulpDiff, maxUlpDiff;
 100     real                         maxUlpDiffPos;
 101     real                         refValMaxUlpDiff, simdValMaxUlpDiff;
 102     bool                         eq, signOk;
 103     int                          i, iter;
 104     int                          niter   = s_nPoints/GMX_SIMD4_WIDTH;
 105     int                          npoints = niter*GMX_SIMD4_WIDTH;
 106 #    if GMX_DOUBLE
 107     union {
 108         double r; std::int64_t i;
 109     } conv0, conv1;
 110 #    else
 111     union {
 112         float  r; std::int32_t i;
 113     } conv0, conv1;
 114 #    endif
 115
 116     maxUlpDiff = 0;
 117     dx         = (range_.second-range_.first)/npoints;
 118
 119     for (iter = 0; iter < niter; iter++)
 120     {
 121         for (i = 0; i < GMX_SIMD4_WIDTH; i++)
 122         {
 123             vx[i]   = range_.first+dx*(iter*GMX_SIMD4_WIDTH+i);
 124             vref[i] = refFunc(vx[i]);
 125         }
 126         vtst  = simd4Real2Vector(simd4Func(vector2Simd4Real(vx)));
 127
 128         for (i = 0, eq = true, signOk = true; i < GMX_SIMD4_WIDTH && eq == true; i++)
 129         {
 130             eq     = eq && ( fabs(vref[i]-vtst[i]) < absTol_ );
 131             signOk = signOk && ( vref[i]*vtst[i] >= 0 );
 132         }
 133         if (eq == true)
 134         {
 135             // Go to next point if everything within absolute tolerance
 136             continue;
 137         }
 138         else if (signOk == false)
 139         {
 140             return ::testing::AssertionFailure()
 141                    << "Failing SIMD4 math function comparison due to sign differences." << std::endl
 142                    << "Reference function: " << refFuncExpr << std::endl
 143                    << "Simd function:      " << simd4FuncExpr << std::endl
 144                    << "Test range is ( " << range_.first << " , " << range_.second << " ) " << std::endl
 145                    << "First sign difference around x=" << std::setprecision(20) << ::testing::PrintToString(vx) << std::endl
 146                    << "Ref values:   " << std::setprecision(20) << ::testing::PrintToString(vref) << std::endl
 147                    << "SIMD4 values: " << std::setprecision(20) << ::testing::PrintToString(vtst) << std::endl;
 148         }
 149         /* We replicate the trivial ulp differences comparison here rather than
 150          * calling the lower-level routine for comparing them, since this enables
 151          * us to run through the entire test range and report the largest deviation
 152          * without lots of extra glue routines.
 153          */
 154         for (i = 0; i < GMX_SIMD4_WIDTH; i++)
 155         {
 156             conv0.r = vref[i];
 157             conv1.r = vtst[i];
 158             ulpDiff = llabs(conv0.i-conv1.i);
 159             if (ulpDiff > maxUlpDiff)
 160             {
 161                 maxUlpDiff        = ulpDiff;
 162                 maxUlpDiffPos     = vx[i];
 163                 refValMaxUlpDiff  = vref[i];
 164                 simdValMaxUlpDiff = vtst[i];
 165             }
 166         }
 167     }
 168
 169     if (maxUlpDiff <= ulpTol_)
 170     {
 171         return ::testing::AssertionSuccess();
 172     }
 173     else
 174     {
 175         return ::testing::AssertionFailure()
 176                << "Failing SIMD4 math function ulp comparison between " << refFuncExpr << " and " << simd4FuncExpr << std::endl
 177                << "Requested ulp tolerance: " << ulpTol_ << std::endl
 178                << "Requested abs tolerance: " << absTol_ << std::endl
 179                << "Largest Ulp difference occurs for x=" << std::setprecision(20) << maxUlpDiffPos << std::endl
 180                << "Ref  values:  " << std::setprecision(20) << refValMaxUlpDiff << std::endl
 181                << "SIMD4 values: " << std::setprecision(20) << simdValMaxUlpDiff << std::endl
 182                << "Ulp diff.:   " << std::setprecision(20) << maxUlpDiff << std::endl;
 183     }
 184 }
 185
 186 /*! \} */
 187 /*! \endcond */
 188
 189 // Actual math function tests below
 190
 191 namespace
 192 {
 193
 194 /*! \cond internal */
 195 /*! \addtogroup module_simd */
 196 /*! \{ */
 197
 198 /*! \brief Function wrapper to evaluate reference 1/sqrt(x) */
 199 static real
 200 refInvsqrt(real x)
 201 {
 202     return 1.0/std::sqrt(x);
 203 }
 204
 205 TEST_F(Simd4MathTest, invsqrt)
 206 {
 207     setRange(1e-10, 1e10);
 208     GMX_EXPECT_SIMD4_FUNC_NEAR(refInvsqrt, invsqrt);
 209 }
 210
 211 TEST_F(Simd4MathTest, invsqrtSingleaccuracy)
 212 {
 213     setRange(1e-10, 1e10);
 214     /* Increase the allowed error by the difference between the actual precision and single */
 215     setUlpTol(ulpTol_ * (1LL << (std::numeric_limits<real>::digits-std::numeric_limits<float>::digits)));
 216     GMX_EXPECT_SIMD4_FUNC_NEAR(refInvsqrt, invsqrtSingleAccuracy);
 217 }
 218
 219 }      // namespace
 220
 221 #endif // GMX_SIMD4_HAVE_REAL
 222
 223 /*! \} */
 224 /*! \endcond */
 225
 226 }      // namespace
 227 }      // namespace
 228
 229 #endif // GMX_SIMD