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/*! \internal \file
 * \brief
 * Tests structure similarity measures rmsd and size-independent rho factor.
 *
 * \author Christian Blau <cblau@gwdg.de>
 * \ingroup module_math
 */
#include "gmxpre.h"

#include <array>

#include <gtest/gtest.h>

#include "gromacs/math/do_fit.h"
#include "gromacs/math/vec.h"

#include "testutils/testasserts.h"

namespace
{

using gmx::RVec;
using gmx::test::defaultRealTolerance;
class StructureSimilarityTest : public ::testing::Test
{
protected:
    static constexpr int       c_nAtoms = 4;
    std::array<RVec, c_nAtoms> structureA_{ { { 1, 0, 0 }, { 0, 1, 0 }, { 0, 0, 1 }, { 0, 0, 0 } } };
    std::array<RVec, c_nAtoms> structureB_{ { { 0, 1, 0 }, { 0, 0, 1 }, { 1, 0, 0 }, { 0, 0, 0 } } };
    std::array<real, c_nAtoms> masses_{ { 1, 1, 1, 0 } };
    std::array<int, 3>         index_{ { 0, 1, 2 } };
    rvec*                      x1_ = gmx::as_rvec_array(structureA_.data());
    rvec*                      x2_ = gmx::as_rvec_array(structureB_.data());
    real*                      m_  = masses_.data();
};

TEST_F(StructureSimilarityTest, StructureComparedToSelfHasZeroRMSD)
{
    EXPECT_REAL_EQ_TOL(0., rmsdev(c_nAtoms, m_, x1_, x1_), defaultRealTolerance());
}

TEST_F(StructureSimilarityTest, StructureComparedToSelfHasZeroRho)
{
    EXPECT_REAL_EQ_TOL(0., rhodev(c_nAtoms, m_, x1_, x1_), defaultRealTolerance());
}

TEST_F(StructureSimilarityTest, YieldsCorrectRMSD)
{
    EXPECT_REAL_EQ_TOL(sqrt(2.0), rmsdev(c_nAtoms, m_, x1_, x2_), defaultRealTolerance());
}

TEST_F(StructureSimilarityTest, YieldsCorrectRho)
{
    EXPECT_REAL_EQ_TOL(2., rhodev(c_nAtoms, m_, x1_, x2_), defaultRealTolerance());
}

TEST_F(StructureSimilarityTest, YieldsCorrectRMSDWithIndex)
{
    EXPECT_REAL_EQ_TOL(
            sqrt(2.0), rmsdev_ind(index_.size(), index_.data(), m_, x1_, x2_), defaultRealTolerance());
}

TEST_F(StructureSimilarityTest, YieldsCorrectRhoWidthIndex)
{
    EXPECT_REAL_EQ_TOL(2., rhodev_ind(index_.size(), index_.data(), m_, x1_, x2_), defaultRealTolerance());
}

} // namespace
