[alexxy/gromacs.git] / src / gromacs / simd / tests / simd.h

/*
 * This file is part of the GROMACS molecular simulation package.
 *
 * Copyright (c) 2014, by the GROMACS development team, led by
 * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
 * and including many others, as listed in the AUTHORS file in the
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#ifndef GMX_SIMD_TESTS_SIMD_H
#define GMX_SIMD_TESTS_SIMD_H

/*! \internal \file
 * \brief
 * Declares fixture for testing of normal SIMD (not SIMD4) functionality.
 *
 * The SIMD tests are both simple and complicated. The actual testing logic
 * is \a very straightforward since we just need to test single values against
 * the math library, and for some math functions we need to do it in a loop.
 * This could have been achieved in minutes with the default Google Test tools,
 * if it wasn't for the problem that we cannot access or compare SIMD contents
 * directly without using lots of other SIMD functionality. For this reason
 * we have separate the basic testing of load/store operations into a separate
 * bootstrapping test. Once this works, we use a set of utility routines to
 * convert SIMD contents to/from std:vector<> and perform the rest of the tests,
 * which then can farmed out to the base class SimdBaseTest that is common
 * to SIMD and SIMD4.
 *
 * Another complication is that the width of the SIMD implementation will
 * depend on the hardware and precision. For some simple operations it is
 * sufficient to set all SIMD elements to the same value, and check that the
 * result is present in all elements. However, for a few more complex
 * instructions that might rely on shuffling under-the-hood it is important
 * that we can test operations with different elements. We achieve this by
 * having test code that can initialize a SIMD variable from an std::vector
 * of arbitrary length; the vector is simply repeated to fill all elements in
 * the SIMD variable. We also have similar routines to compare a SIMD result
 * with values in a vector, which returns true iff all elements match.
 *
 * This way we can write simple tests that use different values for all SIMD
 * elements. Personally I like using vectors of length 3, since this means
 * there are no simple repeated patterns in low/high halves of SIMD variables
 * that are 2,4,8,or 16 elements wide, and we still don't have to care about
 * the exact SIMD width of the underlying implementation.
 *
 * Note that this utility uses a few SIMD load/store instructions internally -
 * those have been tested separately in the bootstrap_loadstore.cpp file.
 *
 * \author Erik Lindahl <erik.lindahl@scilifelab.se>
 * \ingroup module_simd
 */
#include <vector>
#include <gtest/gtest.h>
#include "gromacs/simd/simd.h"

#include "base.h"

namespace gmx
{
namespace test
{

/*! \cond internal */
/*! \addtogroup module_simd */
/*! \{ */

/* Unfortunately we cannot keep static SIMD constants in the test fixture class.
 * The problem is that SIMD memory need to be aligned, and in particular
 * this applies to automatic storage of variables in classes. For SSE registers
 * this means 16-byte alignment (which seems to work), but AVX requires 32-bit
 * alignment. At least both gcc-4.7.3 and Apple clang-5.0 (OS X 10.9) fail to
 * align these variables when they are stored as data in a class.
 *
 * In theory we could set some of these on-the-fly e.g. with setSimdFrom3R()
 * instead (although that would mean repeating code between tests), but many of
 * the constants depend on the current precision not to mention they
 * occasionally have many digits that need to be exactly right, and keeping
 * them in a single place makes sure they are consistent.
 */
#ifdef GMX_SIMD_HAVE_REAL
extern const gmx_simd_real_t rSimd_1_2_3;     //!< Generic (different) fp values.
extern const gmx_simd_real_t rSimd_4_5_6;     //!< Generic (different) fp values.
extern const gmx_simd_real_t rSimd_7_8_9;     //!< Generic (different) fp values.
extern const gmx_simd_real_t rSimd_5_7_9;     //!< rSimd_1_2_3 + rSimd_4_5_6.
extern const gmx_simd_real_t rSimd_m1_m2_m3;  //!< Generic negative floating-point values.
extern const gmx_simd_real_t rSimd_3_1_4;     //!< Used to test min/max.
extern const gmx_simd_real_t rSimd_m3_m1_m4;  //!< negative rSimd_3_1_4.
extern const gmx_simd_real_t rSimd_2p25;      //!< Value that rounds down.
extern const gmx_simd_real_t rSimd_3p75;      //!< Value that rounds up.
extern const gmx_simd_real_t rSimd_m2p25;     //!< Negative value that rounds up.
extern const gmx_simd_real_t rSimd_m3p75;     //!< Negative value that rounds down.
//! Three large floating-point values whose exponents are >32.
extern const gmx_simd_real_t rSimd_Exp;
#    if (defined GMX_SIMD_HAVE_DOUBLE) && (defined GMX_DOUBLE)
// Make sure we also test exponents outside single precision when we use double
extern const gmx_simd_real_t rSimd_ExpDouble;
#    endif
// Magic FP numbers corresponding to specific bit patterns
extern const gmx_simd_real_t rSimd_Bits1;       //!< Pattern F0 repeated to fill single/double.
extern const gmx_simd_real_t rSimd_Bits2;       //!< Pattern CC repeated to fill single/double.
extern const gmx_simd_real_t rSimd_Bits3;       //!< Pattern C0 repeated to fill single/double.
extern const gmx_simd_real_t rSimd_Bits4;       //!< Pattern 0C repeated to fill single/double.
extern const gmx_simd_real_t rSimd_Bits5;       //!< Pattern FC repeated to fill single/double.
extern const gmx_simd_real_t rSimd_Bits6;       //!< Pattern 3C repeated to fill single/double.
#endif                                          // GMX_SIMD_HAVE_REAL
#ifdef GMX_SIMD_HAVE_INT32
extern const gmx_simd_int32_t iSimd_1_2_3;      //!< Three generic ints.
extern const gmx_simd_int32_t iSimd_4_5_6;      //!< Three generic ints.
extern const gmx_simd_int32_t iSimd_7_8_9;      //!< Three generic ints.
extern const gmx_simd_int32_t iSimd_5_7_9;      //!< iSimd_1_2_3 + iSimd_4_5_6.
extern const gmx_simd_int32_t iSimd_1M_2M_3M;   //!< Term1 for 32bit add/sub.
extern const gmx_simd_int32_t iSimd_4M_5M_6M;   //!< Term2 for 32bit add/sub.
extern const gmx_simd_int32_t iSimd_5M_7M_9M;   //!< iSimd_1M_2M_3M + iSimd_4M_5M_6M.
extern const gmx_simd_int32_t iSimd_0xF0F0F0F0; //!< Bitpattern to test integer logical operations.
extern const gmx_simd_int32_t iSimd_0xCCCCCCCC; //!< Bitpattern to test integer logical operations.
#endif                                          // GMX_SIMD_HAVE_INT32


/*! \internal
 * \brief
 * Test fixture for SIMD tests.
 *
 * This is a very simple test fixture that basically just takes the common
 * SIMD/SIMD4 functionality from SimdBaseTest and creates wrapper routines
 * specific for normal SIMD functionality.
 */
class SimdTest : public SimdBaseTest
{
    public:
#ifdef GMX_SIMD_HAVE_REAL
        /*! \brief Compare two real SIMD variables for approximate equality.
         *
         * This is an internal implementation routine. YOu should always use
         * GMX_EXPECT_SIMD_REAL_NEAR() instead.
         *
         * This routine is designed according to the Google test specs, so the char
         * strings will describe the arguments to the macro.
         *
         * The comparison is applied to each element, and it returns true if each element
         * in the SIMD test variable is within the class tolerances of the corresponding
         * reference element.
         */
            ::testing::AssertionResult
        compareSimdRealUlp(const char * refExpr, const char * tstExpr,
                           const gmx_simd_real_t ref, const gmx_simd_real_t tst);

        /*! \brief Compare two real SIMD variables for exact equality.
         *
         * This is an internal implementation routine. YOu should always use
         * GMX_EXPECT_SIMD_REAL_NEAR() instead.
         *
         * This routine is designed according to the Google test specs, so the char
         * strings will describe the arguments to the macro.
         *
         * The comparison is applied to each element, and it returns true if each element
         * in the SIMD test variable is within the class tolerances of the corresponding
         * reference element.
         */
        ::testing::AssertionResult
        compareSimdRealEq(const char * refExpr, const char * tstExpr,
                          const gmx_simd_real_t ref, const gmx_simd_real_t tst);

#endif

#ifdef GMX_SIMD_HAVE_INT32
        /*! \brief Compare two 32-bit integer SIMD variables.
         *
         * This is an internal implementation routine. YOu should always use
         * GMX_EXPECT_SIMD_INT_EQ() instead.
         *
         * This routine is designed according to the Google test specs, so the char
         * strings will describe the arguments to the macro, while the SIMD and
         * tolerance arguments are used to decide if the values are approximately equal.
         *
         * The comparison is applied to each element, and it returns true if each element
         * in the SIMD variable tst is identical to the corresponding reference element.
         */
            ::testing::AssertionResult
        compareSimdInt32(const char * refExpr, const char *  tstExpr,
                         const gmx_simd_int32_t ref, const gmx_simd_int32_t tst);
#endif
};

#ifdef GMX_SIMD_HAVE_REAL
/*! \brief Convert SIMD real to std::vector<real>.
 *
 * The returned vector will have the same length as the SIMD width.
 */
std::vector<real> simdReal2Vector(const gmx_simd_real_t simd);

/*! \brief Return floating-point SIMD value from std::vector<real>.
 *
 * If the vector is longer than SIMD width, only the first elements will be used.
 * If it is shorter, the contents will be repeated to fill the SIMD register.
 */
gmx_simd_real_t   vector2SimdReal(const std::vector<real> &v);

/*! \brief Set SIMD register contents from three real values.
 *
 * Our reason for using three values is that 3 is not a factor in any known
 * SIMD width, so this way there will not be any simple repeated patterns e.g.
 * between the low/high 64/128/256 bits in the SIMD register, which could hide bugs.
 */
gmx_simd_real_t   setSimdRealFrom3R(real r0, real r1, real r2);

/*! \brief Set SIMD register contents from single real value.
 *
 * All elements is set from the given value. This is effectively the same
 * operation as gmx_simd_set1_r(), but is implemented using only load/store
 * operations that have been tested separately in the bootstrapping tests.
 */
gmx_simd_real_t   setSimdRealFrom1R(real value);

/*! \brief Test if a SIMD real is bitwise identical to reference SIMD value. */
#define GMX_EXPECT_SIMD_REAL_EQ(ref, tst)   EXPECT_PRED_FORMAT2(compareSimdRealEq, ref, tst)

/*! \brief Test if a SIMD real is within tolerance of reference SIMD value. */
#define GMX_EXPECT_SIMD_REAL_NEAR(ref, tst) EXPECT_PRED_FORMAT2(compareSimdRealUlp, ref, tst)

#endif  // GMX_SIMD_HAVE_REAL

#ifdef GMX_SIMD_HAVE_INT32
/*! \brief Convert SIMD integer to std::vector<int>.
 *
 * The returned vector will have the same length as the SIMD width.
 */
std::vector<int>   simdInt2Vector(const gmx_simd_int32_t simd);

/*! \brief Return 32-bit integer SIMD value from std::vector<int>.
 *
 * If the vector is longer than SIMD width, only the first elements will be used.
 * If it is shorter, the contents will be repeated to fill the SIMD register.
 */
gmx_simd_int32_t   vector2SimdInt(const std::vector<int> &v);

/*! \brief Set SIMD register contents from three int values.
 *
 * Our reason for using three values is that 3 is not a factor in any known
 * SIMD width, so this way there will not be any simple repeated patterns e.g.
 * between the low/high 64/128/256 bits in the SIMD register, which could hide bugs.
 */
gmx_simd_int32_t   setSimdIntFrom3I(int i0, int i1, int i2);

/*! \brief Set SIMD register contents from single integer value.
 *
 * All elements is set from the given value. This is effectively the same
 * operation as gmx_simd_set1_i(), but is implemented using only load/store
 * operations that have been tested separately in the bootstrapping tests.
 */
gmx_simd_int32_t   setSimdIntFrom1I(int value);

/*! \brief Macro that checks SIMD integer expression against SIMD or reference int.
 *
 * If the reference argument is a scalar integer it will be expanded into
 * the width of the SIMD register and tested against all elements.
 */
#define GMX_EXPECT_SIMD_INT_EQ(ref, tst)    EXPECT_PRED_FORMAT2(compareSimdInt32, ref, tst)

#endif  // GMX_SIMD_HAVE_INT32

/*! \} */
/*! \endcond */

}      // namespace
}      // namespace

#endif // GMX_SIMD_TESTS_SIMD_H