pytorch_kinematics/tests/test_transform.py

import torch
import pytorch_kinematics.transforms as tf


def test_transform():
    N = 20
    mats = tf.random_rotations(N, dtype=torch.float64, device="cpu", requires_grad=True)
    assert list(mats.shape) == [N, 3, 3]
    # test batch conversions
    quat = tf.matrix_to_quaternion(mats)
    assert list(quat.shape) == [N, 4]
    mats_recovered = tf.quaternion_to_matrix(quat)
    assert torch.allclose(mats, mats_recovered)

    quat_identity = tf.quaternion_multiply(quat, tf.quaternion_invert(quat))
    assert torch.allclose(tf.quaternion_to_matrix(quat_identity), torch.eye(3, dtype=torch.float64).repeat(N, 1, 1))


def test_translations():
    t = tf.Translate(1, 2, 3)
    points = torch.tensor([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.5, 0.5, 0.0]]).view(
        1, 3, 3
    )
    points_out = t.transform_points(points)
    points_out_expected = torch.tensor(
        [[2.0, 2.0, 3.0], [1.0, 3.0, 3.0], [1.5, 2.5, 3.0]]
    ).view(1, 3, 3)
    assert torch.allclose(points_out, points_out_expected)

    N = 20
    points = torch.randn((N, N, 3))
    translation = torch.randn((N, 3))
    transforms = tf.Transform3d(pos=translation)
    translated_points = transforms.transform_points(points)
    assert torch.allclose(translated_points, translation.repeat(N, 1, 1).transpose(0, 1) + points)
    returned_points = transforms.inverse().transform_points(translated_points)
    assert torch.allclose(returned_points, points, atol=1e-6)


def test_rotate_axis_angle():
    t = tf.Transform3d().rotate_axis_angle(90.0, axis="Z")
    points = torch.tensor([[0.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 1.0, 1.0]]).view(
        1, 3, 3
    )
    normals = torch.tensor(
        [[1.0, 0.0, 0.0], [1.0, 0.0, 0.0], [1.0, 0.0, 0.0]]
    ).view(1, 3, 3)
    points_out = t.transform_points(points)
    normals_out = t.transform_normals(normals)
    points_out_expected = torch.tensor(
        [[0.0, 0.0, 0.0], [-1.0, 0.0, 0.0], [-1.0, 0.0, 1.0]]
    ).view(1, 3, 3)
    normals_out_expected = torch.tensor(
        [[0.0, 1.0, 0.0], [0.0, 1.0, 0.0], [0.0, 1.0, 0.0]]
    ).view(1, 3, 3)
    assert torch.allclose(points_out, points_out_expected)
    assert torch.allclose(normals_out, normals_out_expected)


def test_rotate():
    R = tf.so3_exp_map(torch.randn((1, 3)))
    t = tf.Transform3d().rotate(R)
    points = torch.tensor([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.5, 0.5, 0.0]]).view(
        1, 3, 3
    )
    normals = torch.tensor(
        [[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [1.0, 1.0, 0.0]]
    ).view(1, 3, 3)
    points_out = t.transform_points(points)
    normals_out = t.transform_normals(normals)
    points_out_expected = torch.bmm(points, R.transpose(-1, -2))
    normals_out_expected = torch.bmm(normals, R.transpose(-1, -2))
    assert torch.allclose(points_out, points_out_expected)
    assert torch.allclose(normals_out, normals_out_expected)
    for i in range(3):
        assert torch.allclose(points_out[0, i], R @ points[0, i])
        assert torch.allclose(normals_out[0, i], R @ normals[0, i])


def test_transform_combined():
    R = tf.so3_exp_map(torch.randn((1, 3)))
    tr = torch.randn((1, 3))
    t = tf.Transform3d(rot=R, pos=tr)
    N = 10
    points = torch.randn((N, 3))
    normals = torch.randn((N, 3))
    points_out = t.transform_points(points)
    normals_out = t.transform_normals(normals)
    for i in range(N):
        assert torch.allclose(points_out[i], R @ points[i] + tr)
        assert torch.allclose(normals_out[i], R @ normals[i])


def test_euler():
    euler_angles = torch.tensor([1, 0, 0.5])
    t = tf.Transform3d(rot=euler_angles)
    sxyz_matrix = torch.tensor([[0.87758256, -0.47942554, 0., 0., ],
                                [0.25903472, 0.47415988, -0.84147098, 0.],
                                [0.40342268, 0.73846026, 0.54030231, 0.],
                                [0., 0., 0., 1.]])
    # from tf.transformations import euler_matrix
    # print(euler_matrix(*euler_angles, "rxyz"))
    # print(t.get_matrix())
    assert torch.allclose(sxyz_matrix, t.get_matrix())


def test_quaternions():
    n = 10
    q = tf.random_quaternions(n)
    q_tf = tf.wxyz_to_xyzw(q)
    assert torch.allclose(q, tf.xyzw_to_wxyz(q_tf))


if __name__ == "__main__":
    test_transform()
    test_translations()
    test_rotate_axis_angle()
    test_rotate()
    test_euler()
    test_quaternions()