goulu/points_on_sphere.py

## points_on_sphere.py
def points_on_sphere(N):
    """ Generate N evenly distributed points on the unit sphere centered at
        the origin. Uses the 'Golden Spiral'.
        Code by Chris Colbert from the numpy-discussion list.
    """
    import numpy as np
    phi = (1 + np.sqrt(5)) / 2  # the golden ratio
    long_incr = 2*np.pi / phi   # how much to increment the longitude

    dz = 2.0 / float(N)         # a unit sphere has diameter 2
    bands = np.arange(N)        # each band will have one point placed on it
    z = bands * dz - 1 + (dz/2) # the height z of each band/point
    r = np.sqrt(1 - z*z)        # project onto xy-plane
    az = bands * long_incr      # azimuthal angle of point modulo 2 pi
    x = r * np.cos(az)
    y = r * np.sin(az)
    return x, y, z
	def points_on_sphere(N):
	""" Generate N evenly distributed points on the unit sphere centered at
	the origin. Uses the 'Golden Spiral'.
	Code by Chris Colbert from the numpy-discussion list.
	"""
	import numpy as np
	phi = (1 + np.sqrt(5)) / 2 # the golden ratio
	long_incr = 2*np.pi / phi # how much to increment the longitude

	dz = 2.0 / float(N) # a unit sphere has diameter 2
	bands = np.arange(N) # each band will have one point placed on it
	z = bands * dz - 1 + (dz/2) # the height z of each band/point
	r = np.sqrt(1 - z*z) # project onto xy-plane
	az = bands * long_incr # azimuthal angle of point modulo 2 pi
	x = r * np.cos(az)
	y = r * np.sin(az)
	return x, y, z