def center_of_mass_polyline_xy_numba(polyline):
""" Compute the center of mass of polyline edges in the XY plane, defined as an array of points.
Parameters
----------
polyline : array
XY(Z) coordinates representing the corners of a polyline (m x 3).
Returns
-------
array
The XY(Z) coordinates of the center of mass.
"""
L = 0
cx = 0
cy = 0
m = polyline.shape[0]
ii = list(range(1, m)) + [0]
for i in range(m):
p1 = polyline[i, :]
p2 = polyline[ii[i], :]
d = length_vector_xy_numba(subtract_vectors_xy_numba(p2, p1))
cx += 0.5 * d * (p1[0] + p2[0])
cy += 0.5 * d * (p1[1] + p2[1])
L += d
c = array([cx, cy, 0.])
sc = 1. / L
return scale_vector_numba(c, factor=sc)
def midpoint_point_point_numba(u, v):
"""Compute the midpoint of two points.
Parameters
----------
u : array
XYZ coordinates of the first point.
v : array
XYZ coordinates of the second point.
Returns
-------
array
XYZ coordinates of the midpoint.
"""
return scale_vector_numba(add_vectors_numba(u, v), factor=0.5)
def centroid_points_numba(u):
"""Compute the centroid of a set of points.
Parameters
----------
u : array
An array of XYZ coordinates.
Returns
-------
array
Centroid of the points.
"""
m = u.shape[0]
sc = 1. / m
return scale_vector_numba(sum_vectors_numba(u, axis=0), factor=sc)