Read Subfind Data

read_subfind_header(filename::String)

Reads the header of a subfind file or file base (without .0, .1, etc.) into a SubfindHeader struct.

read_subfind(filename::String, blockname::String)

Example

To read e.g. the virial radius of halos use

R_vir = read_subfind(filename, "RVIR")

read_subfind(filename::String, blockname::String, ids::AbstractVector{<:Integer}; return_haloid::Bool=false)

Reads the block at the given subfind indices (ids, 0-indexed).

If return_haloid is true, returns a tuple of the block array and the corresponding HaloIDs.

Example

# Read the virial masses of the first four halos in subfind:
mvir = read_subfind(filebase, "MVIR", [0, 1, 2, 3])

# or:
mvir, haloids = read_subfind(filebase, "MVIR", [0, 1, 2, 3]; return_haloid=true)

filter_subfind(sub_base::String, filter_function::Function, files=nothing)

Filters all entries in a subfind file that fulfill the 'filter_funcion' requirements and returns a Vector of HaloIDs.

Examples

# load packages
using GadgetIO, GadgetUnits

# define filter function
function find_mvir_gt_1e15(filename) 
    h = read_header(filename)
    GU = GadgetPhysical(h) # unit conversion

    # read Mvir and convert to solar masses 
    M = read_subfind(filename, "MVIR") .* GU.m_msun

    return findall(M .> 1.0e15)
end

# basename of subfind output (without .*)
sub_base = /path/to/groups_000/sub_000

# get relevant halos from first 10 files
halo_ids = filter_subfind(sub_base, find_mvir_gt_1e15, 0:9)

save_halo_ids(filename::String, halo_ids::Vector{HaloID})

Writes a Vector of HaloIDs to a files.

save_halo_ids(filename::String)

Loads a Vector of HaloIDs from a file.

halo_ids_to_read_positions(halo_ids::Vector{HaloID})

Convert a Vector of HaloIDs to a dictionary of read_positions. To be used with read_blocks_filtered.

read_halo_prop(sub_base, haloid::HaloID, blockname::AbstractString; verbose::Bool=true)

Get halo property from block blockname by halo id. Returns an array or scalar depending on the block type.

read_halo_prop(sub_base, i_global::Integer, blockname::AbstractString; verbose::Bool=true)

Get halo property from block blockname by global halo index i_global (zero-based index).

read_halo_prop(sub_base, blocks::AbstractVector{<:AbstractString}, haloids::AbstractVector{HaloID}; verbose::Bool=true)

Get halo properties defined by an Array of blocks for an Array of HaloIDs. Please note that this only works if all blocks are of the same halo type. Returns a dictionary with all requested blocks.

read_halo_prop(sub_base, blocks::AbstractVector{<:AbstractString}, haloid::HaloID; verbose::Bool=true)

Get halo properties defined by an Array of blocks for a HaloID. Please note that this only works if all blocks are of the same halo type. Returns a dictionary with all requested blocks.

read_halo_prop(sub_base, block::AbstractString, haloids::AbstractVector{HaloID}; verbose::Bool=true)

Get halo properties defined by the block for an Array of HaloIDs. Returns an array with the requested block.

read_halo_prop(sub_base, blocks::AbstractVector{<:AbstractString}, i_global::AbstractVector{<:Integer}; verbose::Bool=true)

Get halo properties defined by an Array of blocks for an Array of global indices. Please note that this only works if all blocks are of the same halo type. Returns a dictionary with all requested blocks.

read_halo_prop(sub_base, blocks::AbstractVector{<:AbstractString}, i_global::Integer; verbose::Bool=true)

Get halo properties defined by an Array of blocks for a global index. Please note that this only works if all blocks are of the same halo type. Returns a dictionary with all requested blocks.

read_halo_prop(sub_base, block::AbstractString, i_global::AbstractVector{<:Integer}; verbose::Bool=true)

Get halo properties defined by the block for an Array of global indices. Returns an array with the requested block.

read_halo_prop_and_id(sub_base, blockname::AbstractString, i_global::Integer; verbose::Bool=true)

Get halo property and HaloID from block blockname by global halo index i_global (zero-based index). nfiles should generally be set to h.num_files, obtained from read_header. When nfiles is not passed, it is read automatically from the header.

global_idxs_to_halo_id(sub_base::String, idxs::Vector{<:Integer}; 
                        parttype::Integer=0)

Converts global halo indices to HaloIDs.

global_idxs_to_halo_id(sub_base::String, offset::Integer, n_to_read::Integer;
                        parttype::Integer=0)

Converts a given number of indices defined by offset and n_to_read to HaloIDs.

read_particles_in_halo(snap_base::String, blocks::Array{String},
                            sub_base::String, halo::HaloID; 
                            radius::Union{Real,Nothing}=nothing,
                            rad_scale::Real=1.0, halo_type::Integer=1,
                            parttype::Integer=0, verbose::Bool=true,
                            use_keys::Bool=true)

Reads all particles of type parttype that are contained in a halo defined by its HaloID. If radius is given (in simulation units), particles are read within at least this radius times rad_scale. Otherwise, R200, RMEA, or RHMS times rad_scale is used depending on halo_type (1, 1, and 2, respectively). Returns a Dict with each of the blocks as entries.

read_particles_in_halo( snap_base::String, block::String,
                        sub_base::String, halo::HaloID; 
                        kwargs...)

Reads all particles of type parttype that are contained in a halo defined by its HaloID. If radius is given (in simulation units), particles are read within at least this radius times rad_scale. Otherwise, R200, RMEA, or RHMS times rad_scale is used depending on halo_type (1, 1, and 2, respectively). Returns an Array with the requested block.