[wpimath] Expand Quaternion class with additional operators (#5600)

Co-authored-by: Tyler Veness <calcmogul@gmail.com>
This commit is contained in:
Jordan McMichael
2023-10-08 19:42:53 -04:00
committed by GitHub
parent 420f2f7c80
commit 33243f982b
9 changed files with 888 additions and 55 deletions

View File

@@ -4,7 +4,9 @@
package edu.wpi.first.math.geometry;
import static org.junit.jupiter.api.Assertions.assertAll;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
import edu.wpi.first.math.util.Units;
import org.junit.jupiter.api.Test;
@@ -14,37 +16,91 @@ class QuaternionTest {
void testInit() {
// Identity
var q1 = new Quaternion();
assertEquals(1.0, q1.getW());
assertEquals(0.0, q1.getX());
assertEquals(0.0, q1.getY());
assertEquals(0.0, q1.getZ());
assertAll(
() -> assertEquals(1.0, q1.getW()),
() -> assertEquals(0.0, q1.getX()),
() -> assertEquals(0.0, q1.getY()),
() -> assertEquals(0.0, q1.getZ()));
// Normalized
var q2 = new Quaternion(0.5, 0.5, 0.5, 0.5);
assertEquals(0.5, q2.getW());
assertEquals(0.5, q2.getX());
assertEquals(0.5, q2.getY());
assertEquals(0.5, q2.getZ());
assertAll(
() -> assertEquals(0.5, q2.getW()),
() -> assertEquals(0.5, q2.getX()),
() -> assertEquals(0.5, q2.getY()),
() -> assertEquals(0.5, q2.getZ()));
// Unnormalized
var q3 = new Quaternion(0.75, 0.3, 0.4, 0.5);
assertEquals(0.75, q3.getW());
assertEquals(0.3, q3.getX());
assertEquals(0.4, q3.getY());
assertEquals(0.5, q3.getZ());
assertAll(
() -> assertEquals(0.75, q3.getW()),
() -> assertEquals(0.3, q3.getX()),
() -> assertEquals(0.4, q3.getY()),
() -> assertEquals(0.5, q3.getZ()));
q3 = q3.normalize();
var q3_norm = q3.normalize();
double norm = Math.sqrt(0.75 * 0.75 + 0.3 * 0.3 + 0.4 * 0.4 + 0.5 * 0.5);
assertEquals(0.75 / norm, q3.getW());
assertEquals(0.3 / norm, q3.getX());
assertEquals(0.4 / norm, q3.getY());
assertEquals(0.5 / norm, q3.getZ());
assertEquals(
1.0,
q3.getW() * q3.getW()
+ q3.getX() * q3.getX()
+ q3.getY() * q3.getY()
+ q3.getZ() * q3.getZ());
assertAll(
() -> assertEquals(0.75 / norm, q3_norm.getW()),
() -> assertEquals(0.3 / norm, q3_norm.getX()),
() -> assertEquals(0.4 / norm, q3_norm.getY()),
() -> assertEquals(0.5 / norm, q3_norm.getZ()),
() -> assertEquals(1.0, q3_norm.dot(q3_norm)));
}
@Test
void testAddition() {
var q = new Quaternion(0.1, 0.2, 0.3, 0.4);
var p = new Quaternion(0.5, 0.6, 0.7, 0.8);
var sum = q.plus(p);
assertAll(
() -> assertEquals(q.getW() + p.getW(), sum.getW()),
() -> assertEquals(q.getX() + p.getX(), sum.getX()),
() -> assertEquals(q.getY() + p.getY(), sum.getY()),
() -> assertEquals(q.getZ() + p.getZ(), sum.getZ()));
}
@Test
void testSubtraction() {
var q = new Quaternion(0.1, 0.2, 0.3, 0.4);
var p = new Quaternion(0.5, 0.6, 0.7, 0.8);
var difference = q.minus(p);
assertAll(
() -> assertEquals(q.getW() - p.getW(), difference.getW()),
() -> assertEquals(q.getX() - p.getX(), difference.getX()),
() -> assertEquals(q.getY() - p.getY(), difference.getY()),
() -> assertEquals(q.getZ() - p.getZ(), difference.getZ()));
}
@Test
void testScalarMultiplication() {
var q = new Quaternion(0.1, 0.2, 0.3, 0.4);
var scalar = 2;
var product = q.times(scalar);
assertAll(
() -> assertEquals(q.getW() * scalar, product.getW()),
() -> assertEquals(q.getX() * scalar, product.getX()),
() -> assertEquals(q.getY() * scalar, product.getY()),
() -> assertEquals(q.getZ() * scalar, product.getZ()));
}
@Test
void testScalarDivision() {
var q = new Quaternion(0.1, 0.2, 0.3, 0.4);
var scalar = 2;
var product = q.divide(scalar);
assertAll(
() -> assertEquals(q.getW() / scalar, product.getW()),
() -> assertEquals(q.getX() / scalar, product.getX()),
() -> assertEquals(q.getY() / scalar, product.getY()),
() -> assertEquals(q.getZ() / scalar, product.getZ()));
}
@Test
@@ -59,31 +115,131 @@ class QuaternionTest {
// 90° CCW X rotation, 90° CCW Y rotation, and 90° CCW Z rotation should
// produce a 90° CCW Y rotation
var expected = yRot;
var actual = zRot.times(yRot).times(xRot);
assertEquals(expected.getW(), actual.getW(), 1e-9);
assertEquals(expected.getX(), actual.getX(), 1e-9);
assertEquals(expected.getY(), actual.getY(), 1e-9);
assertEquals(expected.getZ(), actual.getZ(), 1e-9);
final var actual = zRot.times(yRot).times(xRot);
assertAll(
() -> assertEquals(expected.getW(), actual.getW(), 1e-9),
() -> assertEquals(expected.getX(), actual.getX(), 1e-9),
() -> assertEquals(expected.getY(), actual.getY(), 1e-9),
() -> assertEquals(expected.getZ(), actual.getZ(), 1e-9));
// Identity
var q =
new Quaternion(
0.72760687510899891, 0.29104275004359953, 0.38805700005813276, 0.48507125007266594);
actual = q.times(q.inverse());
assertEquals(1.0, actual.getW());
assertEquals(0.0, actual.getX());
assertEquals(0.0, actual.getY());
assertEquals(0.0, actual.getZ());
final var actual2 = q.times(q.inverse());
assertAll(
() -> assertEquals(1.0, actual2.getW()),
() -> assertEquals(0.0, actual2.getX()),
() -> assertEquals(0.0, actual2.getY()),
() -> assertEquals(0.0, actual2.getZ()));
}
@Test
void testConjugate() {
var q = new Quaternion(0.75, 0.3, 0.4, 0.5);
var inv = q.conjugate();
assertAll(
() -> assertEquals(q.getW(), inv.getW()),
() -> assertEquals(-q.getX(), inv.getX()),
() -> assertEquals(-q.getY(), inv.getY()),
() -> assertEquals(-q.getZ(), inv.getZ()));
}
@Test
void testInverse() {
var q = new Quaternion(0.75, 0.3, 0.4, 0.5);
var inv = q.inverse();
var norm = q.norm();
assertEquals(q.getW(), inv.getW());
assertEquals(-q.getX(), inv.getX());
assertEquals(-q.getY(), inv.getY());
assertEquals(-q.getZ(), inv.getZ());
assertAll(
() -> assertEquals(q.getW() / (norm * norm), inv.getW(), 1e-10),
() -> assertEquals(-q.getX() / (norm * norm), inv.getX(), 1e-10),
() -> assertEquals(-q.getY() / (norm * norm), inv.getY(), 1e-10),
() -> assertEquals(-q.getZ() / (norm * norm), inv.getZ(), 1e-10));
}
@Test
void testNorm() {
var q = new Quaternion(3, 4, 12, 84);
// pythagorean triples (3, 4, 5), (5, 12, 13), (13, 84, 85)
assertEquals(q.norm(), 85, 1e-10);
}
@Test
void testExponential() {
var q = new Quaternion(1.1, 2.2, 3.3, 4.4);
var q_exp =
new Quaternion(
2.81211398529184, -0.392521193481878, -0.588781790222817, -0.785042386963756);
assertEquals(q_exp, q.exp());
}
@Test
void testLogarithm() {
var q = new Quaternion(1.1, 2.2, 3.3, 4.4);
var q_log =
new Quaternion(1.7959088706354, 0.515190292664085, 0.772785438996128, 1.03038058532817);
assertEquals(q_log, q.log());
var zero = new Quaternion(0, 0, 0, 0);
var one = new Quaternion();
assertEquals(zero, one.log());
var i = new Quaternion(0, 1, 0, 0);
assertEquals(i.times(Math.PI / 2), i.log());
var j = new Quaternion(0, 0, 1, 0);
assertEquals(j.times(Math.PI / 2), j.log());
var k = new Quaternion(0, 0, 0, 1);
assertEquals(k.times(Math.PI / 2), k.log());
assertEquals(i.times(-Math.PI), one.times(-1).log());
var ln_half = Math.log(0.5);
assertEquals(new Quaternion(ln_half, -Math.PI, 0, 0), one.times(-0.5).log());
}
@Test
void testLogarithmIsInverseOfExponential() {
var q = new Quaternion(1.1, 2.2, 3.3, 4.4);
// These operations are order-dependent: ln(exp(q)) is congruent
// but not necessarily equal to exp(ln(q)) due to the multi-valued nature of the complex
// logarithm.
var q_log_exp = q.log().exp();
assertEquals(q, q_log_exp);
var start = new Quaternion(1, 2, 3, 4);
var expect = new Quaternion(5, 6, 7, 8);
var twist = start.log(expect);
var actual = start.exp(twist);
assertEquals(expect, actual);
}
@Test
void testDotProduct() {
var q = new Quaternion(1.1, 2.2, 3.3, 4.4);
var p = new Quaternion(5.5, 6.6, 7.7, 8.8);
assertEquals(
q.getW() * p.getW() + q.getX() * p.getX() + q.getY() * p.getY() + q.getZ() * p.getZ(),
q.dot(p));
}
@Test
void testDotProductAsEquality() {
var q = new Quaternion(1.1, 2.2, 3.3, 4.4);
var q_conj = q.conjugate();
assertAll(() -> assertEquals(q, q), () -> assertNotEquals(q, q_conj));
}
}

View File

@@ -44,6 +44,54 @@ TEST(QuaternionTest, Init) {
q3.Z() * q3.Z());
}
TEST(QuaternionTest, Addition) {
Quaternion q{0.1, 0.2, 0.3, 0.4};
Quaternion p{0.5, 0.6, 0.7, 0.8};
auto sum = q + p;
EXPECT_DOUBLE_EQ(q.W() + p.W(), sum.W());
EXPECT_DOUBLE_EQ(q.X() + p.X(), sum.X());
EXPECT_DOUBLE_EQ(q.Y() + p.Y(), sum.Y());
EXPECT_DOUBLE_EQ(q.Z() + p.Z(), sum.Z());
}
TEST(QuaternionTest, Subtraction) {
Quaternion q{0.1, 0.2, 0.3, 0.4};
Quaternion p{0.5, 0.6, 0.7, 0.8};
auto difference = q - p;
EXPECT_DOUBLE_EQ(q.W() - p.W(), difference.W());
EXPECT_DOUBLE_EQ(q.X() - p.X(), difference.X());
EXPECT_DOUBLE_EQ(q.Y() - p.Y(), difference.Y());
EXPECT_DOUBLE_EQ(q.Z() - p.Z(), difference.Z());
}
TEST(QuaternionTest, ScalarMultiplication) {
Quaternion q{0.1, 0.2, 0.3, 0.4};
auto scalar = 2;
auto product = q * scalar;
EXPECT_DOUBLE_EQ(q.W() * scalar, product.W());
EXPECT_DOUBLE_EQ(q.X() * scalar, product.X());
EXPECT_DOUBLE_EQ(q.Y() * scalar, product.Y());
EXPECT_DOUBLE_EQ(q.Z() * scalar, product.Z());
}
TEST(QuaternionTest, ScalarDivision) {
Quaternion q{0.1, 0.2, 0.3, 0.4};
auto scalar = 2;
auto product = q / scalar;
EXPECT_DOUBLE_EQ(q.W() / scalar, product.W());
EXPECT_DOUBLE_EQ(q.X() / scalar, product.X());
EXPECT_DOUBLE_EQ(q.Y() / scalar, product.Y());
EXPECT_DOUBLE_EQ(q.Z() / scalar, product.Z());
}
TEST(QuaternionTest, Multiply) {
// 90° CCW rotations around each axis
double c = units::math::cos(90_deg / 2.0);
@@ -71,13 +119,104 @@ TEST(QuaternionTest, Multiply) {
EXPECT_NEAR(0.0, actual.Z(), 1e-9);
}
TEST(QuaternionTest, Conjugate) {
Quaternion q{0.72760687510899891, 0.29104275004359953, 0.38805700005813276,
0.48507125007266594};
auto conj = q.Conjugate();
EXPECT_DOUBLE_EQ(q.W(), conj.W());
EXPECT_DOUBLE_EQ(-q.X(), conj.X());
EXPECT_DOUBLE_EQ(-q.Y(), conj.Y());
EXPECT_DOUBLE_EQ(-q.Z(), conj.Z());
}
TEST(QuaternionTest, Inverse) {
Quaternion q{0.72760687510899891, 0.29104275004359953, 0.38805700005813276,
0.48507125007266594};
auto norm = q.Norm();
auto inv = q.Inverse();
EXPECT_DOUBLE_EQ(q.W(), inv.W());
EXPECT_DOUBLE_EQ(-q.X(), inv.X());
EXPECT_DOUBLE_EQ(-q.Y(), inv.Y());
EXPECT_DOUBLE_EQ(-q.Z(), inv.Z());
EXPECT_DOUBLE_EQ(q.W() / (norm * norm), inv.W());
EXPECT_DOUBLE_EQ(-q.X() / (norm * norm), inv.X());
EXPECT_DOUBLE_EQ(-q.Y() / (norm * norm), inv.Y());
EXPECT_DOUBLE_EQ(-q.Z() / (norm * norm), inv.Z());
}
TEST(QuaternionTest, Norm) {
Quaternion q{3, 4, 12, 84};
auto norm = q.Norm();
EXPECT_NEAR(85, norm, 1e-9);
}
TEST(QuaternionTest, Exponential) {
Quaternion q{1.1, 2.2, 3.3, 4.4};
Quaternion expect{2.81211398529184, -0.392521193481878, -0.588781790222817,
-0.785042386963756};
auto q_exp = q.Exp();
EXPECT_EQ(expect, q_exp);
}
TEST(QuaternionTest, Logarithm) {
Quaternion q{1.1, 2.2, 3.3, 4.4};
Quaternion expect{1.7959088706354, 0.515190292664085, 0.772785438996128,
1.03038058532817};
auto q_log = q.Log();
EXPECT_EQ(expect, q_log);
Quaternion zero{0, 0, 0, 0};
Quaternion one{1, 0, 0, 0};
Quaternion i{0, 1, 0, 0};
Quaternion j{0, 0, 1, 0};
Quaternion k{0, 0, 0, 1};
Quaternion ln_half{std::log(0.5), -std::numbers::pi, 0, 0};
EXPECT_EQ(zero, one.Log());
EXPECT_EQ(i * std::numbers::pi / 2, i.Log());
EXPECT_EQ(j * std::numbers::pi / 2, j.Log());
EXPECT_EQ(k * std::numbers::pi / 2, k.Log());
EXPECT_EQ(i * -std::numbers::pi, (one * -1).Log());
EXPECT_EQ(ln_half, (one * -0.5).Log());
}
TEST(QuaternionTest, LogarithmAndExponentialInverse) {
Quaternion q{1.1, 2.2, 3.3, 4.4};
// These operations are order-dependent: ln(exp(q)) is congruent but not
// necessarily equal to exp(ln(q)) due to the multi-valued nature of the
// complex logarithm.
auto q_log_exp = q.Log().Exp();
EXPECT_EQ(q, q_log_exp);
Quaternion start{1, 2, 3, 4};
Quaternion expect{5, 6, 7, 8};
auto twist = start.Log(expect);
auto actual = start.Exp(twist);
EXPECT_EQ(expect, actual);
}
TEST(QuaternionTest, DotProduct) {
Quaternion q{1.1, 2.2, 3.3, 4.4};
Quaternion p{5.5, 6.6, 7.7, 8.8};
EXPECT_NEAR(q.W() * p.W() + q.X() * p.X() + q.Y() * p.Y() + q.Z() * p.Z(),
q.Dot(p), 1e-9);
}
TEST(QuaternionTest, DotProductAsEquality) {
Quaternion q{1.1, 2.2, 3.3, 4.4};
auto q_conj = q.Conjugate();
EXPECT_NEAR(q.Dot(q), q.Norm() * q.Norm(), 1e-9);
EXPECT_GT(std::abs(q.Dot(q_conj) - q.Norm() * q_conj.Norm()), 1e-9);
}