AsterRingMaker.py

import random
from datetime import datetime

# AsteroidsRingMaker
# by JackDole
# 2016.03.15 16:36:56
# converted to Python and enhanced by FaceDeer

#daysYear = 365.24218985
#AU = 149597870.691
#eMass = 5.9736e24

#uncomment this line if you want repeatable results
#random.seed(100)

# Amount of asteroids
NumberOfAster=200
# Name of the asteroids - a serial number is appended
AsterName='Vulkanoid'

RingCenter='Sol'

# Orbital radii in AU
InnerRadius=0.15
OuterRadius=0.18

# Radius of asteroids in KM
MaxRadiusOfAster=3
MinRadiusOfAster=0.1

#orbital eccentricity
MaxEccentricity=0.001
MinEccentricity=0

# Orbital inclination +- in degrees
MaxInclination=10

#Probability that the asteroid won't be given a rotation rate, leaving it tide-locked
ChanceOfTideLock = 0.1
#rotation periods in hours. See https://www.boulder.swri.edu/~bottke/rubble/node3.html
MaxRotationPeriod = 12
MinRotationPeriod = 0.1

RefPlane='Ecliptic'
epoch=2457395.5
FileName= '{0}_{1}.sc'.format(AsterName, NumberOfAster)

template ="""
Asteroid "{AsterName} {count}"
{{
\tParentBody\t"{RingCenter}"
\tClass\t\t"Asteroid"
\tRadius\t\t{radius}
{rotation}
\tOrbit
\t{{
\t\tEpoch\t\t\t{epoch}
\t\tSemiMajorAxis\t{semi}
\t\tEccentricity\t{eccen}
\t\tInclination\t\t{incl}
\t\tAscendingNode\t{ascen}
\t\tArgOfPericen\t{argof}
\t\tMeanAnomaly\t\t0.0
\t\tRefPlane\t\t"{RefPlane}"
\t}}
}}

"""

#three different random number generators that give a floating point number between
#the two parameters but with different distributions

def uniform(a, b):
    return random.uniform(a, b)

def triangular(a, b):
    return random.triangular(a, b, (a+b)/2.0)

# A normal distribution placing a and b at three standard deviations out from the mean
# clamping the result so that there are no outliers beyond the desired range
def gaussian(a, b):
    result = random.gauss((a+b)/2.0, (b-a)/6.0)
    return max(min(result, b), a)

randomGenerator = gaussian

parameters = {'AsterName' : AsterName, 'RingCenter' : RingCenter, 'RefPlane' : RefPlane, 'epoch' : epoch}

with open(FileName, 'w') as outputfile:
    outputfile.write('// Asteroids made with AsteroidsRingMaker\n// {0}\n\n'.format(datetime.today()))

    for count in range(NumberOfAster):

        parameters['count'] = count
        parameters['semi'] = randomGenerator(InnerRadius, OuterRadius)
        parameters['radius'] = randomGenerator(MinRadiusOfAster, MaxRadiusOfAster)
        parameters['incl'] = randomGenerator(-MaxInclination, MaxInclination)
        parameters['eccen'] = randomGenerator(MinEccentricity, MaxEccentricity)
        parameters['argof'] = random.uniform(0,360)
        parameters['ascen'] = random.uniform(0,360)

        if random.random() > ChanceOfTideLock:
            rotation = randomGenerator(MinRotationPeriod,MaxRotationPeriod)
            obliquity = random.uniform(0,360)
            parameters['rotation'] = '\tRotationPeriod\t{0}\n\tObliquity\t\t{1}\n'.format(rotation, obliquity)
        else:
            parameters['rotation'] = ''

        outputfile.write(template.format(**parameters))