utils.py

import numpy as np
import torch


def limit_period(val, offset=0.5, period=np.pi):
    return val - torch.floor(val / period + offset) * period


def rotation_3d_in_axis(points, angles, axis=0):
    # points: [N, point_size, 3]
    # angles: [N]
    rot_sin = torch.sin(angles)
    rot_cos = torch.cos(angles)
    ones = torch.ones_like(rot_cos)
    zeros = torch.zeros_like(rot_cos)
    if axis == 1:
        rot_mat_T = torch.stack([
            torch.stack([rot_cos, zeros, -rot_sin]),
            torch.stack([zeros, ones, zeros]),
            torch.stack([rot_sin, zeros, rot_cos])
        ])
    elif axis == 2 or axis == -1:
        rot_mat_T = torch.stack([
            torch.stack([rot_cos, -rot_sin, zeros]),
            torch.stack([rot_sin, rot_cos, zeros]),
            torch.stack([zeros, zeros, ones])
        ])
    elif axis == 0:
        rot_mat_T = torch.stack([
            torch.stack([zeros, rot_cos, -rot_sin]),
            torch.stack([zeros, rot_sin, rot_cos]),
            torch.stack([ones, zeros, zeros])
        ])
    else:
        raise ValueError('axis should in range')

    return torch.einsum('aij,jka->aik', (points, rot_mat_T))