Calculate the number of lights to use for certain quantities.

hueman_light_numbers.py

delta = 0.01

class Light:
	def __init__(self, quantity, priority):
		self.quantity = quantity
		self.priority = priority
		self.n_on = 0


def _do_priority_magic(n_lights, lights):
	if n_lights < len(lights):		
		raise Exception('Not enough lights for scene')

	sumQuantities = sum([l.quantity for l in lights])
	if abs(1 - sumQuantities) > delta:
		# scale quantities to sum to 1
		multiplier = 1 + abs(1 - sumQuantities)
		for l in lights:
			l.quantity *= multiplier
		
	for l in lights:
		l.n_on = iround(l.quantity * n_lights)
	
	light_count = sum([r.n_on for r in lights])	
	while light_count > n_lights:
		# remove a light from the lowest priority item
		lowestPriority = sorted(lights, key=lambda x: x.priority)[0]
		lowestPriority.n_on -= 1
		
		light_count = sum([l.n_on for l in lights])
		
	while light_count < n_lights:
		# add a light to the highest priority item
		highestPriority = sorted(lights, key=lambda x: x.priority, reverse=True)[0]
		highestPriority.n_on += 1
		
		light_count = sum([l.n_on for l in lights])
		
	return lights
		
			
def iround(x):
	"""iround(number) -> integer
	Round a number to the nearest integer."""
	y = round(x) - .5
	return int(y) + (y > 0)
	
l1 = Light(0.5, 1)
l2 = Light(0.5, 2)
lights = [l1, l2]
_do_priority_magic(5, lights)
print([l.n_on for l in lights])