NoName

A code for Computational Cosmology Algorithm Exploration

(2/2016-)

Introduction

NoName is the beginnings of a Computational Cosmology code of so far primarily pedagogical value. Tom Abel has been writing this as part of graduate course at Stanford. It is a flexible enough framework that numerous algorithms may be implemented. Some choices made here are influenced by the enzo and Gadget codes.

Current Features

• Particle Mesh dynamics of collisionless particles
• Comoving Coordinates
• Restart files

Getting Started

The code is intended to be run in the run directory as in: julia --color=yes -i -e "using NoName; gp, gd, p = run_noname();" particle_mesh.conf Here the -i makes julia enter interactive mode after the run is finished and the code prints some instructions which variables hold the results.

This assumes that the LOAD_PATH contains the directory in which to find NoName.jl. You can make sure it is always found by adding push!(LOAD_PATH, "/Users/tabel/Research/codes/noname/src") (make sure to change this to your path!) in your $HOME/.juliarc.jl file.

Dependencies

Add the following packages with Pkg.add("Logging") etc... Currently for AppConf we should use Pkg.checkout("AppConf") to get the latest version that has not been tagged as a release yet.

• Logging for basic and colorful logging
• AppConf for configuration file management
• HDF5 data output
• JLD restart functionality
• ArgParse to parse commandline
• Cosmology for cosmological comoving coordinates
• Roots for basic root finding
• NearestNeighbors for SPH and Friend of friends group finding

Caveats

• No kind of parallelism so far
• Hydro not fully implemented
• My first larger julia code framework so very likely full of idiosyncracies

Configuration files

Basic code behaviour is influenced by the ___.conf files. There is one in the src/default.conf directory which sets up defaults. The user may chose to create directory in their home directory $HOME/.noname/ and store a default.conf there to match their preferences. This user defined file will be read just before the one specified on the command line at invocation julia ../../src/noname.jl particle_mesh.conf. The one on the command line has the last word.

Submodules and functionality

• Input PowerSpectra
• Cosmology

Parameters

# This file specifies all the default parameters for our code
# Check the Source or some of parameter.info outputfiles for a full list
HydroMethod = MUSCL
dims        = (30, 1, 1) # main grid dimensions (active zones)
Nghosts     = ( 3, 3, 3) # ghost zones on each side in each dimension
γ           = 1.66667    # equation of state adiabatic index
DualEnergyFormalism=true # 
DomainLeftEdge  = [0. ,0., 0.]  # Size of Domain: Only tested 0..1 so far
DomainRightEdge = [1., 1., 1.]  # 
CourantFactor = 0.3

cosm_Ωm = .3 # Omega Matter
cosm_h = 0.7 # Hubble constant in units of 100 km/s/Mpc

CurrentOutputNumber=0             # Count Outputs 
OutputDirectory = "/tmp/noname"   # Where to store the output
OutputSeparateDirectories=true    # Create directories for each output
LastOutputCycle = -1
LastOutputTime  = 0.
OutputEveryNCycle = 0
OutputDtDataDump = 0.

verbose = false
RestartFileName = /tmp/restart.jld  #
ProfilingResultsFile = profiling_results.bin 
InitialDt = 0.0000001
MaximumDt = 1e30
StartTime = 0
CurrentTime = 0
StopTime = 0
StartCycle = 0
CurrentCycle = 0
StopCycle = 1000000

ParticleDimensions = [1, 1, 1] # number of particles along each dimension
ParticleDepositInterpolation = cic # none and cic implemented so far
ParticleBackInterpolation    = cic # none and cic implemented so far