import math


def calcCirclePos(robotIdx, numRobots, radius=3, center=(0,0)):
    """
    Helper function to distribute robot positions on a circle.
    """
    gamma = 2*math.pi / numRobots
    x = radius * math.cos(gamma * robotIdx) + center[0]
    y = radius * math.sin(gamma * robotIdx) + center[1]
    phi = gamma * robotIdx - math.pi
    return (x, y, phi)