File Formats:

Data files are in binary unformatted Fortran format. More specifically, in the case of the ΛCDM-W5, RPCDM-W5 and SUCDM-W5 simulations the files are binary big endian unformatted Fortran files, while the data file of the ΛCDM-W7, RPCDM-W7 and wCDM-W7 are binary little endian unformatted Fortran files.

Files containing snapshot particles (field): fof_boxlenX_nY_COSMO_cube_N

Files containing halo positions (halo): fof_boxlenX_nY_COSMO_masst_N

Files containing the halo particles (halo): fof_boxlenX_nY_COSMO_strct_N

where X is the box length of the simulation, Y the cubic root of the number of particles in the simulation, COSMO = (lcdmw5, lcdmw7, rpcdmw5, rpcdmw7, wcdmw7) and N is the file ID number.

File Content:

Files containing snapshot particles:

npart	integer(4)	Number of particles in the field
procid	integer(4)	ID of the cube
boundaries	real(4)*6	xmin, xmax, ymin, ymax, zmin, zmax
positions	real(4)*3*npart	x, y, z position of each particles
velocities	real(4)*3*npart	vx, vy, vz velocity of each particles
ids	int(8)*npart	unique id of each particle

Files containing halo positions:

nhalos	integer(4)	Number of halos in the file
haoid	integer(8)	ID of each halo
apart	integer(4)	Number of particles of each halo
positions	real(4)*3*npart	x, y, z position of each halo centre of mass
velocities	real(4)*3*npart	vx, vy, vz velocity of each halo centre of mass

Files containing halo particles:

npart	integer(4)	Number of particles for each halo
positions	real(4)*3*npart	x, y, z position of each halo centre of mass
velocities	real(4)*3*npart	vx, vy, vz velocity of each halo centre of mass
ids	integer(8)	Unique ID of each particle for each halo

Position and velocities are in RAMSES units. The data files can be read natively in Fortran, or using a C++ library as described below.

Reading Data File Scripts:

In order to read the binary files, you need to use the proper compilation flag to convert the big-endian or little-endian binary of your compiler, e.g. for ifort:

ifort -convert big_endian -O3 my_program.f90 - o my_program

Fortran script for reading field particle velocities and positions from the files containing snapshot particles:

program read_field

    implicit none

    integer(4) :: npart, procID, Ucub, j, i
    real(4) :: xmin, xmax, ymin, ymax, zmin, zmax
    integer(8), allocatable :: id(:)
    real(4), allocatable :: x(:,:), v(:,:)

    Open(Unit=Ucub,file='/path_for_data/ &
    &  fof_boxlen648_n1024_lcdmw5_cube_00001',Form='Unformatted')

    ! read number of particles in the cube
    Read(Ucub) npart

    ! read ID of the FoF process assigned to this cube
    Read(Ucub) procID

    ! read boundary values of the cube
    Read(Ucub) xmin, xmax, ymin, ymax, zmin, zmax

    ! allocate memory
    allocate(id(1:npart))
    allocate(x(1:3,1:npart))
    allocate(v(1:3,1:npart))

    ! read positions 
    Read(Ucub) ((x(j,i),j=1,3),i=1,npart)
    ! read velocities 
    Read(Ucub) ((v(j,i),j=1,3),i=1,npart)
    ! read id's 
    Read(Ucub) (id(i),i=1,npart)
    Close(Ucub)

end program read_field

Fortran script for reading halo mass and centre of mass positions from the files containing halo positions:

program read_masst

    implicit none

    integer(4) :: nhalos, Ucub, j, i, i_halos
    integer(4), allocatable :: nparthalos(:)
    integer(8), allocatable :: id(:)
    real(4),allocatable :: x(:,:)

    Open(Unit=Ucub,file='/path_for_data/ &
    & fof_boxlen648_n1024_lcdmw5_masst_00001',Form='Unformatted')     

    ! read number of halos 
    Read(Ucub) nhalos

    ! allocate memory
    allocate(id(1:nhalos))
    allocate(nparthalos(1:nhalos))
    allocate(x(1:3,1:nhalos))

    do i_halos = 1, nhalos     ! loop over all halos in the file

    ! read number of particles 
    Read(Ucub) id(i_halos), nparthalos(i_halo),((x(j,i_halos),j=1,3)

    end do 

    Close(Ucub)

end program read_masst

Fortran script for reading halo particle positions and velocities from the files containing halo particles:

program read_struct

    implicit none

    integer(4) :: mynpart, Ucub, j, i, mynhalos
    integer(8), allocatable :: id(:)
    real(4),allocatable :: x(:,:),v(:,:)

    Open(Unit=Ucub,file='/path_for_data/ &
    & fof_boxlen648_n1024_lcdmw5_strct_00001',Form='Unformatted')     

    ! read number of halos 
    Read(Ucub) mynhalos

    do i_halos = 1, mynhalos       ! look over all halos in the file

    ! read number of particles 
    Read(Ucub) mynpart

    ! allocate memory
    allocate(id(1:mynpart))
    allocate(x(1:3,1:mynpart))
    allocate(v(1:3,1:mynpart))

    ! read positions 
    Read(Ucub) ((x(j,i),j=1,3),i=1,mynpart)
    ! read velocities
    Read(Ucub) ((v(j,i),j=1,3),i=1,mynpart)
    ! read id's
    Read(Ucub) (id(i),i=1,mynpart)

    end do 

    Close(Ucub)

end program read_struct