accumulated_distance.py

#!/usr/bin/env python
# Software License Agreement (GNU GPLv3  License)
#
# Copyright (c) 2020, Roland Jung (roland.jung@aau.at) , AAU, KPK, NAV
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
# Requirements:
# numpy
########################################################################################################################
import numpy as np


def accumulated_distance(p_vec):
    """"
    sums up elements of
    * [1xM] vector resulting in a [1xM-1] vector.
    * [MxN] matrix resulting a [M-1xN] matrix


    Example:
    >> v = np.array([0, 1, 2, 3, 4, 5])
    >> a = accumulated_distance(p_vec=v) # [1 2 3 4 5]


    Input:
    p_vec -- numpy.ndarray, [1xM] vector or [MxN] matrix

    Output:
    res -- numpy.ndarray, [1xM-1] vector or ,[M-1xN] matrix
    """

    if isinstance(p_vec, np.ndarray):  # and p_vec.ndim == 1:
        motion_vec = np.diff(p_vec, n=1, axis=0)
        return np.cumsum(np.abs(motion_vec), axis=0)
    else:
        raise ValueError('Type error: np.ndarray expected')


def total_distance(p_vec):
    """"
    sums up absolute traversed distance
    * [1xM] vector
    * [MxN] matrix


    Example:
    >> v = np.array([0, 1, 2, 3, 4, 5, -5])
    >> a = total_distance(p_vec=v) # [15]


    Input:
    p_vec -- numpy.ndarray, [1xM] vector or [MxN] matrix

    Output:
    res -- scalar
    """

    if isinstance(p_vec, np.ndarray):
        motion_vec = np.diff(p_vec, n=1, axis=0)
        dist_vec = np.sum(np.abs(motion_vec), axis=0)
        return np.linalg.norm(dist_vec)
    else:
        raise ValueError('Type error: np.ndarray expected')