PGalF Suite: Galaxy Finding Pipeline for RAMSES Simulations

A comprehensive suite for identifying galaxies and halos from RAMSES cosmological simulation outputs. The pipeline processes raw simulation data through domain decomposition, halo finding, and galaxy identification.

Pipeline Overview

RAMSES Output → NewDD → opFoF → NewGalFinder → Galaxy Catalogs
               (Slab)   (Halo)   (Galaxy)

Components

Directory	Description
NewDD	RAMSES domain decomposition into Z-directional slabs for parallel processing
opFoF	MPI-parallel Friends-of-Friends (FoF) halo finder
NewGalFinder	Parallel galaxy/subhalo finder using density peaks and water-shedding
GalCenter	Galaxy center identification utilities

Quick Start

0. Configure Build System

# Default configuration (Intel OneAPI mpiicx/mpiifx compilers, optimized build)
./configure

# Debug build
./configure --debug

# Custom compilers and FFTW path
./configure --cc=mpicc --fc=mpifort --fftw=/path/to/fftw

# See all options
./configure --help

1. Build All Components

make all          # Build everything
# Or build individually:
make galcenter    # Build GalCenter only
make galfinder    # Build NewGalFinder only
make newdd        # Build NewDD only

2. Domain Decomposition

mpirun -np 8 ./NewDD/newdd.exe <snapshot> <nsplit>

3. Halo Finding

cd opFoF
make this
mpirun -np 8 ./opfof.exe <snapshot> <nfiles>

4. Galaxy Finding

mpirun -np 64 ./NewGalFinder/gfind.exe <snapshot>

Build System

The project uses a configure script to generate Makefiles for all subdirectories from Makefile.in templates.

File	Description
configure	Build configuration script
Makefile.in	Top-level Makefile template
GalCenter/Makefile.in	GalCenter Makefile template
NewGalFinder/Makefile.in	NewGalFinder Makefile template
NewDD/Makefile.in	NewDD Makefile template

Configure Options

Option	Default	Description
--cc=CC	mpiicx	C compiler for GalCenter/NewDD
--fc=FC	mpiifx	Fortran compiler for GalCenter/NewDD
--galfinder-cc=CC	mpiicx	C compiler for NewGalFinder
--galfinder-fc=FC	mpiifx	Fortran compiler for NewGalFinder
--fftw=PATH	/home/kjhan/local	FFTW installation path
--opt=FLAGS	-O3	Optimization flags
--debug	-	Use -g debug flags
--openmp=FLAGS	-qopenmp	OpenMP flags
--no-openmp	-	Disable OpenMP

Per-component options (e.g., --galcenter-nmeg=N, --galfinder-nchem=N, --newdd-ndust=N) are also available. Run ./configure --help for the full list.

Shared Files

• ramses.h - RAMSES data structure definitions
• params.h - Algorithm parameters
• libmyram.a - Custom memory management library

Documentation

Each subdirectory contains detailed documentation:

• NewDD/README.md - Domain decomposition details
• opFoF/README.md - FoF algorithm and usage
• NewGalFinder/README.md - Galaxy finder algorithm

Requirements

• MPI (OpenMPI, MPICH, or Intel MPI)
• Intel or GCC compilers with OpenMP support
• FFTW3 library (for NewGalFinder)

Output Units

Quantity	Unit
Position	comoving Mpc/h
Velocity	km/s
Mass	Msun/h

License

For scientific research purposes.