File: TestSmallMatrix.cpp

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/* -------------------------------------------------------------------------- *
 *                       Simbody(tm): SimTKcommon                             *
 * -------------------------------------------------------------------------- *
 * This is part of the SimTK biosimulation toolkit originating from           *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org/home/simbody.  *
 *                                                                            *
 * Portions copyright (c) 2008-12 Stanford University and the Authors.        *
 * Authors: Peter Eastman                                                     *
 * Contributors: Michael Sherman                                              *
 *                                                                            *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may    *
 * not use this file except in compliance with the License. You may obtain a  *
 * copy of the License at http://www.apache.org/licenses/LICENSE-2.0.         *
 *                                                                            *
 * Unless required by applicable law or agreed to in writing, software        *
 * distributed under the License is distributed on an "AS IS" BASIS,          *
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   *
 * See the License for the specific language governing permissions and        *
 * limitations under the License.                                             *
 * -------------------------------------------------------------------------- */

#include "SimTKcommon.h"
#include "SimTKcommon/Testing.h"

#include <iostream>

using std::cout;
using std::endl;
using namespace SimTK;
using namespace std;

// A matrix operation of size N can be expected to achieve an
// accuracy of about N*tol where tol is the expected accuracy
// of a scalar operation.

template <int N>
void testInverse() {
    Mat<N,N> identity(1);
    Mat<N,N> mat = Test::randMat<N,N>();
    SimTK_TEST_EQ_SIZE(mat*mat.invert(), identity, N);
    mat = ~mat;
    SimTK_TEST_EQ_SIZE(mat*mat.invert(), identity, N);
    SimTK_TEST_EQ_SIZE((-mat)*(-mat).invert(), identity, N);
}

void testDotProducts() {
    Vec3 v1(1, 2, 3);
    Vec3 v2(-1, -2, -3);
    Row3 r1(0.1, 0.2, 0.3);
    Row3 r2(-0.1, -0.2, -0.3);
    SimTK_TEST_EQ(dot(v1, v2), -14.0);
    SimTK_TEST_EQ(dot(r1, r2), -0.14);
    SimTK_TEST_EQ(dot(v1, r2), -1.4);
    SimTK_TEST_EQ(dot(r1, v2), -1.4);
    SimTK_TEST_EQ(r1*v2, -1.4);
    SpatialVec sv(Vec3(1, 2, 3), Vec3(4, 5, 6));
    SpatialRow sr(Row3(1, 2, 3), Row3(4, 5, 6));
    SimTK_TEST_EQ(sr*sv, 91.0);
}

void testCrossProducts() {
    const Vec3 w = Test::randVec3();
    const Vec3 v = Test::randVec3();
    const Vec3 wp = UnitVec3(w).perp() * Test::randReal();
    const Vec3 vp = UnitVec3(v).perp() * Test::randReal();
    const Mat33 vx = crossMat(v);
    const Mat33 wx = crossMat(w);
    const Mat33 vpx = crossMat(vp);
    const Mat33 wpx = crossMat(wp);

    const Mat33 m33 = Test::randMat33();
    const Mat34 m = Test::randMat<3,4>();
    const Mat43 mt = ~m;
    const Mat<3,1> m1 = Test::randMat<3,1>();


    SimTK_TEST_EQ( w%v, Vec3(w[1]*v[2]-w[2]*v[1],
                                w[2]*v[0]-w[0]*v[2],
                                w[0]*v[1]-w[1]*v[0]) );

    SimTK_TEST_EQ(  w %  v,  cross(  w,  v));
    SimTK_TEST_EQ( ~w % ~v, -cross( ~v, ~w));

    SimTK_TEST_EQ( wx*v, w % v );
    SimTK_TEST_EQ( crossMat(~w), wx );
    SimTK_TEST_EQ( crossMat(-w), ~wx );
    SimTK_TEST_EQ( crossMatSq(w)*v, -w % (w%v) );

    // cross(vector, matrix) (columnwise)
    Mat34 c = v % m;
    SimTK_TEST_EQ(c(0), v%m(0));
    SimTK_TEST_EQ(c(1), v%m(1));
    SimTK_TEST_EQ(c(2), v%m(2));
    SimTK_TEST_EQ(c(3), v%m(3));
    SimTK_TEST_EQ(c, vx*m);
    SimTK_TEST_EQ(c, (~v)%m); // row same as col here

    Mat<3,1> c1 = v % m1;
    SimTK_TEST_EQ(c1(0), v%m1(0));

    // cross(matrix, vector) (rowwise)
    Mat43 cr = mt % w;
    SimTK_TEST_EQ(cr[0], mt[0]%w);
    SimTK_TEST_EQ(cr[1], mt[1]%w);
    SimTK_TEST_EQ(cr[2], mt[2]%w);
    SimTK_TEST_EQ(cr[3], mt[3]%w);
    SimTK_TEST_EQ(cr, mt*wx);
    SimTK_TEST_EQ(cr, mt % (~w)); // row same as col here

    SimTK_TEST_EQ( vx * m33 * vx, v % m33 % v );
}

// Individually test 2x2, 3x3, and 4x4 because the
// smaller sizes may have specialized inline operators.
void testSymMat() {
    // 2x2
    const Vec3   a = Test::randVec3();
    const Vec<2> v = Test::randVec<2>();
    SymMat<2> sm( a[0],
                  a[1], a[2] );
    Mat<2,2>   m( a[0], a[1],
                  a[1], a[2] );

    SimTK_TEST_EQ( (Mat<2,2>(sm)), m );
    SimTK_TEST_EQ( sm, SymMat<2>().setFromSymmetric(m) );

    SimTK_TEST_EQ( sm*v, m*v );
    SimTK_TEST_EQ( ~v*sm, ~v*m );

    // 3x3
    const Vec<6> a3 = Test::randVec<6>();
    const Vec<3> v3 = Test::randVec<3>();
    SymMat<3> sm3( a3[0],
                   a3[1], a3[2],
                   a3[3], a3[4], a3[5]);
    Mat<3,3>   m3( a3[0], a3[1], a3[3],
                   a3[1], a3[2], a3[4],
                   a3[3], a3[4], a3[5]);

    SimTK_TEST_EQ( (Mat<3,3>(sm3)), m3 );
    SimTK_TEST_EQ( sm3, SymMat<3>().setFromSymmetric(m3) );

    SimTK_TEST_EQ( sm3*v3, m3*v3 );
    SimTK_TEST_EQ( ~v3*sm3, ~v3*m3 );

    // 4x4 (hopefully the general case)
    const Vec<10> a4 = Test::randVec<10>();
    const Vec<4>  v4 = Test::randVec<4>();
    SymMat<4> sm4( a4[0],
                   a4[1], a4[2],
                   a4[3], a4[4], a4[5],
                   a4[6], a4[7], a4[8], a4[9]);
    Mat<4,4>   m4( a4[0], a4[1], a4[3], a4[6],
                   a4[1], a4[2], a4[4], a4[7],
                   a4[3], a4[4], a4[5], a4[8],
                   a4[6], a4[7], a4[8], a4[9]);

    SimTK_TEST_EQ( (Mat<4,4>(sm4)), m4 );
    SimTK_TEST_EQ( sm4, SymMat<4>().setFromSymmetric(m4) );

    SimTK_TEST_EQ( sm4*v4, m4*v4 );
    SimTK_TEST_EQ( ~v4*sm4, ~v4*m4 );


    // Complex is tricky for symmetric (really Hermitian) matrices because
    // the diagonals must be real and the corresponding off-diagonals are
    // complex conjugate pairs, NOT the same value even though the off
    // diagonal data is only stored once.
    const Vec<3,Complex> ac( Test::randComplex(), Test::randComplex(), Test::randComplex() );
    const Vec<2,Complex> vc( Test::randComplex(), Test::randComplex() );
    SymMat<2,Complex> smc( ac[0],
                           ac[1], ac[2] );
    Mat<2,2,Complex>   mc( ac[0].real(), std::conj(ac[1]),
                           ac[1],         ac[2].real() );

    // This constructor has to figure out how to generate a conjugate 
    // element for the upper right in the full Mat.
    Mat<2,2,Complex> sm2mc(smc);
    SimTK_TEST_EQ( sm2mc, mc );
    SimTK_TEST_EQ( smc, (SymMat<2,Complex>().setFromSymmetric(mc)) );

    SimTK_TEST_EQ( smc*vc, mc*vc );
    SimTK_TEST_EQ( ~vc*smc, ~vc*mc );

    SimTK_TEST_EQ( ~smc*vc, ~mc*vc );
    SimTK_TEST_EQ( ~smc*vc, smc*vc );    
}

void testNumericallyEqual() {
    Mat<3,4,float> fm1(1), fm1e(1), fm1n(1), fm1nz(1);
    fm1e(1,1) += (float)(0.5*fm1.getDefaultTolerance()); // should test equal
    fm1n(2,2) += (float)(2  *fm1.getDefaultTolerance()); // should test not equal
    fm1nz(1,3) = (float)(2  *fm1.getDefaultTolerance()); // should test not equal

    const Mat<3,4,float> fmident34( 1, 0, 0, 0,
                                    0, 1, 0, 0,
                                    0, 0, 1, 0 );



    SimTK_TEST(fm1==fmident34); // exact
    SimTK_TEST(fm1.isNumericallyEqual(fm1));
    SimTK_TEST(fm1.isNumericallyEqual(fm1e));
    SimTK_TEST(!fm1.isNumericallyEqual(fm1n));
    SimTK_TEST(!fm1.isNumericallyEqual(fm1nz));
    SimTK_TEST((fm1.getSubMat<3,3>(0,0).isNumericallyEqual(fm1nz.getSubMat<3,3>(0,0))));
    SimTK_TEST((fm1e.getSubMat<3,3>(0,0).isNumericallyEqual(fm1nz.getSubMat<3,3>(0,0))));
    SimTK_TEST(!(fm1n.getSubMat<3,3>(0,0).isNumericallyEqual(fm1nz.getSubMat<3,3>(0,0))));

    // Tightening tolerance should make fm1e not equal.
    SimTK_TEST(!fm1.isNumericallyEqual(fm1e, .3*fm1.getDefaultTolerance()));
    SimTK_TEST(fm1.isNumericallyEqual(1.f));
    SimTK_TEST(fm1e.isNumericallyEqual(1.f));
    SimTK_TEST(!fm1n.isNumericallyEqual(1.f));

    Mat<3,4,double> dm1(1), dfm1e(fm1e);
    // Try mixed-precision.
    SimTK_TEST(dm1.isNumericallyEqual(fm1));
    SimTK_TEST(dm1.isNumericallyEqual(fm1e)); // because should use float tolerance
    SimTK_TEST(!dm1.isNumericallyEqual(dfm1e)); // because should use double tolerance
    SimTK_TEST(dm1.isNumericallyEqual(dfm1e, fm1e.getDefaultTolerance())); // force float tolerance

    // Repeat for symmetric matrix.

    SymMat<3,float> fs1(1), fs1e(1), fs1n(1), fs1nz(1);
    fs1e(1,1) += (float)(0.5*fs1.getDefaultTolerance()); // should test equal
    fs1n(2,2) += (float)(2  *fs1.getDefaultTolerance()); // should test not equal
    fs1nz(2,1) = (float)(2  *fs1.getDefaultTolerance()); // should test not equal

    const SymMat<3,float> fsident3( 1, 
                                    0, 1, 
                                    0, 0, 1 );

    SimTK_TEST(fs1==fsident3); // exact
    SimTK_TEST(fs1.isNumericallyEqual(fs1));
    SimTK_TEST(fs1.isNumericallyEqual(fs1e));
    SimTK_TEST(!fs1.isNumericallyEqual(fs1n));
    SimTK_TEST(!fs1.isNumericallyEqual(fs1nz));
    // Tightening tolerance should make fs1e not equal.
    SimTK_TEST(!fs1.isNumericallyEqual(fs1e, .3*fs1.getDefaultTolerance()));
    SimTK_TEST(fs1.isNumericallyEqual(1.f));
    SimTK_TEST(fs1e.isNumericallyEqual(1.f));
    SimTK_TEST(!fs1n.isNumericallyEqual(1.f));

    SymMat<3,double> ds1(1), dfs1e(fs1e);
    // Try mixed-precision.
    SimTK_TEST(ds1.isNumericallyEqual(fs1));
    SimTK_TEST(ds1.isNumericallyEqual(fs1e)); // because should use float tolerance
    SimTK_TEST(!ds1.isNumericallyEqual(dfs1e)); // because should use double tolerance
    SimTK_TEST(ds1.isNumericallyEqual(dfs1e, fs1e.getDefaultTolerance())); // force float tolerance

    // Check Vec and Row.

    Vec<3,float> fv1(1), fv1e(1), fv1n(1); // should be 1 1 1
    Row<3,float> fr1(1);
    fv1e[1] += (float)(0.5*fv1.getDefaultTolerance()); // should test equal
    fv1n[0] += (float)(2  *fv1.getDefaultTolerance()); // should test not equal

    const Vec<3,float> fone(1,1,1);
    SimTK_TEST(fv1==fone); // exact
    SimTK_TEST(fv1.isNumericallyEqual(fv1));
    SimTK_TEST(fv1.isNumericallyEqual(fv1e));
    SimTK_TEST(!fv1.isNumericallyEqual(fv1n));

    SimTK_TEST(fr1==~fone); // exact
    SimTK_TEST(fr1.isNumericallyEqual(~fv1));
    SimTK_TEST(fr1.isNumericallyEqual(~fv1e));
    SimTK_TEST(!fr1.isNumericallyEqual(~fv1n));

    // Check symmetry tests in Mat.
    Mat<2,7,double> notSquare(0); // can't be symmetric
    SimTK_TEST(!notSquare.isExactlySymmetric());
    SimTK_TEST(!notSquare.isNumericallySymmetric());

    Mat<3,3,float> f33(1),       // exactly symmetric
                   f33e(1),      // numerically symmetric
                   f33n(1);      // too sloppy
    f33e(1,2) += (float)(0.5*f33.getDefaultTolerance()); // should test equal
    f33n(2,0) += (float)(2  *f33.getDefaultTolerance()); // should test not equal

    SimTK_TEST(f33.isExactlySymmetric());
    SimTK_TEST(!f33e.isExactlySymmetric());
    SimTK_TEST(!f33n.isExactlySymmetric());
    SimTK_TEST(f33.isNumericallySymmetric());
    SimTK_TEST(f33e.isNumericallySymmetric());
    SimTK_TEST(!f33n.isNumericallySymmetric());

    // Things are trickier for complex matrices where symmetry means
    // Hermitian (conjugate) symmetry.
    // This one has *positional* symmetry, not Hermitian.
    Mat<2,2, std::complex<double> > mcp( std::complex<double>(1,2), std::complex<double>(3,4),
                                         std::complex<double>(3,4), std::complex<double>(5,6) );
    // This one is Hermitian. 
    Mat<2,2, std::complex<double> > mch( std::complex<double>(1,0), std::complex<double>(3,-4),
                                         std::complex<double>(3,4), std::complex<double>(5,0) );

    SimTK_TEST(!mcp.isExactlySymmetric());
    SimTK_TEST(!mcp.isNumericallySymmetric());

    SimTK_TEST(mch.isExactlySymmetric());
    SimTK_TEST(mch.isNumericallySymmetric());

    // This should be OK because mch is symmetric.
    SymMat<2, std::complex<double> > symTest;
    symTest.setFromSymmetric(mch);

    mch(0,1) += 0.5*mch.getDefaultTolerance();
    SimTK_TEST(!mch.isExactlySymmetric());
    SimTK_TEST(mch.isNumericallySymmetric());

    // This should be OK because mch is almost symmetric.
    symTest.setFromSymmetric(mch);

    mch(0,1) += 5*mch.getDefaultTolerance();
    SimTK_TEST(!mch.isExactlySymmetric());
    SimTK_TEST(!mch.isNumericallySymmetric());


    // This should throw in Debug mode because mch is too far off.
    #ifndef NDEBUG
    SimTK_TEST_MUST_THROW(symTest.setFromSymmetric(mch));
    #endif

}

static bool isXAxis(const UnitVec3& test) {return test==UnitVec3(1,0,0);}
static bool isNegZAxis(const UnitVec3& test) {return test==UnitVec3(0,0,-1);}

void testUnitVec() {
    SimTK_TEST_EQ(Vec3(UnitVec3(1,1,0)), Vec3(Sqrt2/2,Sqrt2/2,0));
    SimTK_TEST(UnitVec3(XAxis) == UnitVec3(1,0,0));
    SimTK_TEST(UnitVec3(YAxis) == UnitVec3(0,1,0));
    SimTK_TEST(UnitVec3(ZAxis) == UnitVec3(0,0,1));
    SimTK_TEST(UnitVec3(NegXAxis) == UnitVec3(-1,0,0));
    SimTK_TEST(UnitVec3(NegYAxis) == UnitVec3(0,-1,0));
    SimTK_TEST(UnitVec3(NegZAxis) == UnitVec3(0,0,-1));

    SimTK_TEST(isXAxis(XAxis)); // implicit conversion
    SimTK_TEST(!isXAxis(YAxis)); // implicit conversion
    SimTK_TEST(isNegZAxis(NegZAxis)); // implicit conversion
    SimTK_TEST(!isNegZAxis(NegYAxis)); // implicit conversion
    SimTK_TEST(!isNegZAxis(ZAxis)); // implicit conversion

    SimTK_TEST(XAxis.dotProduct(XAxis) == 1);
    SimTK_TEST(XAxis.dotProduct(YAxis) == 0);
    SimTK_TEST(XAxis.dotProduct(ZAxis) == 0);
    SimTK_TEST(ZAxis.dotProduct(YAxis) == 0);

    SimTK_TEST(XAxis.crossProductSign(XAxis) == 0);

    SimTK_TEST(XAxis.crossProductAxis(YAxis) == ZAxis);
    SimTK_TEST(XAxis.crossProductSign(YAxis) == 1);

    SimTK_TEST(XAxis.crossProductAxis(ZAxis) == YAxis);
    SimTK_TEST(XAxis.crossProductSign(ZAxis) == -1);

    SimTK_TEST(ZAxis.crossProductAxis(XAxis) == YAxis);
    SimTK_TEST(ZAxis.crossProductSign(XAxis) == 1);

    int sign;
    CoordinateAxis axis = ZAxis.crossProduct(YAxis, sign);
    SimTK_TEST(CoordinateDirection(axis,sign) == NegXAxis);

    SimTK_TEST(CoordinateDirection(YAxis,CoordinateDirection::Negative()) 
               == NegYAxis);

    SimTK_TEST(-XAxis == NegXAxis);
    SimTK_TEST(-YAxis == NegYAxis);
    SimTK_TEST(-ZAxis == NegZAxis);
    SimTK_TEST(-ZAxis != NegYAxis);
    SimTK_TEST(ZAxis == -NegZAxis);
    SimTK_TEST(-(-NegXAxis) == -XAxis);
    SimTK_TEST(-(-NegYAxis) == -(-(-YAxis)));

    SimTK_TEST(NegXAxis.crossProductAxis(NegYAxis) == ZAxis);
    SimTK_TEST(NegYAxis.crossProductAxis(ZAxis) == XAxis);
    SimTK_TEST(NegYAxis.crossProductSign(ZAxis) == -1);
    SimTK_TEST(NegYAxis.crossProductSign(NegZAxis) == 1);


}

// Test append/drop/insert rows and columns.
void testAppendRowCol() {
    Mat34 m34( 1,  2,  3,  4,
               5,  6,  7,  8,
               9, 10, 11, 12);

    Mat44 m44 = m34.appendRow(Row4(-1, -2, -3, -4));
    SimTK_TEST(m44==Mat44(  1,  2,  3,  4,
                            5,  6,  7,  8,
                            9, 10, 11, 12,
                           -1, -2, -3, -4));
    m44 = m34.insertRow(0, Row4(-1, -2, -3, -4));
    SimTK_TEST(m44==Mat44( -1, -2, -3, -4,
                            1,  2,  3,  4,
                            5,  6,  7,  8,
                            9, 10, 11, 12));

    m44 = m34.insertRow(1, Row4(-1, -2, -3, -4));
    SimTK_TEST(m44==Mat44(  1,  2,  3,  4,
                           -1, -2, -3, -4,
                            5,  6,  7,  8,
                            9, 10, 11, 12));

    m44 = m34.insertRow(3, Row4(-1, -2, -3, -4));
    SimTK_TEST(m44==m34.appendRow(Row4(-1, -2, -3, -4)));

    Mat35 m35 = m34.appendCol(Vec3(-6, -7, -8));
    SimTK_TEST(m35==Mat35( 1,  2,  3,  4, -6,
                           5,  6,  7,  8, -7,
                           9, 10, 11, 12, -8));

    m35 = m34.insertCol(0, Vec3(-6, -7, -8));
    SimTK_TEST(m35==Mat35( -6, 1,  2,  3,  4, 
                           -7, 5,  6,  7,  8, 
                           -8, 9, 10, 11, 12));

    m35 = m34.insertCol(2, Vec3(-6, -7, -8));
    SimTK_TEST(m35==Mat35( 1,  2, -6,  3,  4, 
                           5,  6, -7,  7,  8, 
                           9, 10, -8, 11, 12));

    m35 = m34.insertCol(4, Vec3(-6, -7, -8));
    SimTK_TEST(m35==m34.appendCol(Vec3(-6, -7, -8)));

    Mat45 m45 = m34.appendRowCol(Row5(-1, -2, -3, -4, -5),
                                 Vec4(-6, -7, -8, -9));
    SimTK_TEST(m45==Mat45( Row5(1,  2,  3,  4, -6),
                           Row5(5,  6,  7,  8, -7),
                           Row5(9, 10, 11, 12, -8),
                           Row5(-1, -2, -3, -4, -9)));

    m45 = m34.insertRowCol(0,0, Row5(-1, -2, -3, -4, -5),
                                Vec4(-6, -7, -8, -9));
    SimTK_TEST(m45==Mat45( Row5(-6, -2, -3, -4, -5),
                           Row5(-7,  1,  2,  3,  4),
                           Row5(-8,  5,  6,  7,  8),
                           Row5(-9,  9, 10, 11, 12)));



    m45 = m34.insertRowCol(1,2, Row5(-1, -2, -3, -4, -5),
                                Vec4(-6, -7, -8, -9));
    SimTK_TEST(m45==Mat45( Row5( 1,  2, -6,  3,  4),
                           Row5(-1, -2, -7, -4, -5),
                           Row5( 5,  6, -8,  7,  8),
                           Row5( 9, 10, -9, 11, 12)));

    m45 = m34.insertRowCol(3,4, Row5(-1, -2, -3, -4, -5),
                                Vec4(-6, -7, -8, -9));
    SimTK_TEST(m45== m34.appendRowCol(Row5(-1, -2, -3, -4, -5),
                                      Vec4(-6, -7, -8, -9)));

    Mat24 m24_0 = m34.dropRow(0);
    Mat24 m24_1 = m34.dropRow(1);
    Mat24 m24_2 = m34.dropRow(2);

    SimTK_TEST(m24_0==Mat24(5,  6,  7,  8,
                            9, 10, 11, 12));
    SimTK_TEST(m24_1==Mat24(1,  2,  3,  4,
                            9, 10, 11, 12));
    SimTK_TEST(m24_2==Mat24(1,  2,  3,  4,
                            5,  6,  7,  8));

    Mat33 m33_0 = m34.dropCol(0);
    Mat33 m33_1 = m34.dropCol(1);
    Mat33 m33_2 = m34.dropCol(2);
    Mat33 m33_3 = m34.dropCol(3);

    SimTK_TEST(m33_0==Mat33( 2,  3,  4,
                             6,  7,  8,
                            10, 11, 12));
    SimTK_TEST(m33_1==Mat33( 1,  3,  4,
                             5,  7,  8,
                             9, 11, 12));
    SimTK_TEST(m33_2==Mat33( 1,  2,  4,
                             5,  6,  8,
                             9, 10, 12));
    SimTK_TEST(m33_3==Mat33( 1,  2,  3,
                             5,  6,  7,
                             9, 10, 11));

}

int main() {
    SimTK_START_TEST("TestSmallMatrix");
        SimTK_SUBTEST(testSymMat);
        SimTK_SUBTEST(testInverse<1>);
        SimTK_SUBTEST(testInverse<2>);
        SimTK_SUBTEST(testInverse<3>);
        SimTK_SUBTEST(testInverse<5>);
        SimTK_SUBTEST(testInverse<10>);
        SimTK_SUBTEST(testDotProducts);
        SimTK_SUBTEST(testCrossProducts);
        SimTK_SUBTEST(testNumericallyEqual);
        SimTK_SUBTEST(testUnitVec);
        SimTK_SUBTEST(testAppendRowCol);
    SimTK_END_TEST();
}