There are two files: analyze.py and simulate.cc. You are intended to run analyze.py, which compiles and runs simulate.cc itself.

Dependencies

You will need python3 and g++. I am using "Python 3.6.9" and "g++ (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0", although any recent version should work.

Inputs

analyze.py takes the following arguments
--n The power in the origin-time power-law. You may pass a comma-separated list of values
--N The number of potential civilizations.
--sc The ratio s/c - how fast civs expand relative to the speed of light. You may pass a comma-separated list of values.
--s The speed of civilization expansion (default 1.0)
--m The power in the universe expansion scale factor (default 2/3; see section "8 Cosmology")
--D The dimensions of space. Should be 1,2 or 3 (default 3)
--L The size of the universe (default 1.0)
--seed A random seed (default 0)
--empty_samples How precisely to estimate how full the universe is (default 0, meaning no estimate at all)

Outputs

Each run of simulate.cc will produce two output files, one ending in "civs.csv" and one ending in "years.csv"
analyze.py will run simulate.cc once for each combination of parameters you give it. For instance, if you give "--n 10,12" and "--c 1.0,2.0", then simulate.cc will run four times: once with n=10,c=1.0, once with n=10,c=2.0, once with n=12,c=1.0 and once with n=12,c=2.0

The "civs" file contains the following columns, with one row per "surviving" civilization:

• D columns (X,Y,Z) for the position in space
  
• OriginTime: The model/conformal OriginTime
  
• MinArrival: The model time when another civilization first arrives at our origin point
  
• MinSee: The model time when we first see signals from another civilization
  
• NumberSeen: The number of alien civilizations we see signals from at our origin time
  
• MaxAngle: How much of the sky another civilization takes up in our sky at our origin time (section 10 H; between 0 and pi)
  
• PctEmpty: An estimate of how much of the universe is empty at our origin time
  
• Volume: An estimate of what fraction of the universe this civ eventually controls
  

The "years" file contains the following columns, all in "clock" years:

• OriginTime: Sampled distribution of civilization origin times
  
• MinWait: Sampled distribution of how long civilizations will have to wait to meet another civilization
  
• MinSETI: Sampled distribution of how long civilizations will have to wait to see signals from another civilization
  

analyze.py will combine statistics from these simulations into a graph, with different values of "n" as different datasets and different values of "c" as columns of graphs.

Examples

To generate figure 13: time python3 analyze.py --D 3 --n 1.5,3,6,12 --N 1e8 --sc 1.0,0.75,0.5,0.25 --L 1 --s 1 --seed 0 --empty 100

To generate table 1: time python3 analyze.py --D 3 --n 6,12 --N 1e8 --sc 0.5,0.75 --L 1 --s 1 --seed 0 --empty 100 --table_1

To generate data for figure 12: time python3 analyze.py --D 3 --n 1.5,3,6,12 --N 1e8 --sc 1.0 --L 1 --s 1 --seed 0 --figure_12

Help: python3 analyze.py --help

You can reach me at [email protected]