Introduction
This section guides the export of simulation data in the VTK (Visualization Toolkit) format, a widely recognized standard for 3D visualization in scientific computing. The exported files are compatible with visualization tools like ParaView (an open-source software), allowing for detailed analysis and rendering of complex datasets. Both the exported hydro cells and particle data can be opened together in ParaView. For certain functions, multi-threading is used (this feature is experimental). To utilize this, load Julia or your Jupyter Notebook with multiple threads, and the multi-threading will be applied automatically. Paraview can also be used remotely running on a server with MPI.
You can download the necessary files here: https://www.paraview.org.
using Mera?export_vtk Export hydro data to VTK format for visualization in tools like
ParaView.
--------------------------
• export data that is present in your database and can be processed
by getvar() (done internally)
• select scalar(s) and their unit(s)
• select a vector and its unit (like velocity)
• export data in log10
• creates binary files with optional compression
• supports multi-threading
-> generating per-level VTU files for scalar and optionally vector data and
creates corresponding VTM multiblock container files to reference these VTU
files.
export_vtk(
dataobject::HydroDataType, outprefix::String;
scalars::Vector{Symbol} = [:rho],
scalars_unit::Vector{Symbol} = [:nH],
scalars_log10::Bool=false,
vector::Array{<:Any,1}=issing, missing, missing],
vector_unit::Symbol = :km_s,
vector_name::String = "velocity",
vector_log10::Bool=false,
positions_unit::Symbol = :standard,
lmin::Int = dataobject.lmin,
lmax::Int = dataobject.lmax,
chunk_size::Int = 50000,
compress::Bool = true,
interpolate_higher_levels::Bool = true,
max_cells::Int = 100_000_000,
verbose::Bool = true,
myargs::ArgumentsType=ArgumentsType()
)
Arguments
---------
Required:
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• dataobject::HydroDataType: The AMR data structure from MERA.jl
containing variables like level, position, and physical
quantities.
• outprefix::String: The base path and prefix for output files
(e.g., "output/data" will create files like "output/data_L0.vtu").
Predefined/Optional Keywords:
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• scalars: List of scalar variables to export (default is :rho);
from the database or a predefined quantity (see field: info,
function getvar(), dataobject.data)
• scalars_unit: Sets the unit for the list of scalars (default is
hydrogen number density in cm^-3).
• scalars_log10: Apply log10 to the scalars (default false).
• vector: List of vector component variables to export (default is
missing); exports vector data as separate VTU files
• vector_unit: Sets the unit for the vector components (default is
km/s).
• vector_name: The name of the vector field in the VTK file
(default: "velocity").
• vector_log10: Apply log10 to the vector components (default:
false).
• positions_unit: Sets the unit of the cell positions (default: code
units); usefull in paraview to select regions
• lmin: Minimum AMR level to process (default: simulations lmin);
smaller levels are excluded in export
• lmax: Maximum AMR level to process (default: simulations lmax);
existing higher levels are interpolated down if
interpolatehigherlevels is true, otherwise excluded from export
• chunk_size::Int = 50000: Size of data chunks for processing
(currently unused but reserved for future optimizations).
• chunk_size::Int = 50000: Size of data chunks for processing
(currently unused but reserved for future optimizations).
• compress: If true (default), enable compression.
• interpolate_higher_levels: If true, interpolate data from higher
levels down to given lmax .
• max_cells: Maximum number of cells to export per level (caps
output if exceeded, prioritizing denser regions), (default:
100000000)
• verbose: If true (default), print detailed progress and diagnostic
messages.
────────────────────────────────────────────────────────────────────────────
Export particle data to VTK format for visualization in tools like
ParaView.
--------------------------
• export data that is present in your database and can be processed
by getvar() (done internally)
• select scalar(s) and their unit(s)
• select a vector and its unit (like velocity)
• export data in log10
• creates binary files with optional compression
• supports multi-threading
-> generates VTU files; each particle is represented as a vertex point with
associated scalar and vector data.
export_vtk(
dataobject::PartDataType, outprefix::String;
scalars::Vector{Symbol} = [:mass],
scalars_unit::Vector{Symbol} = [:Msol],
scalars_log10::Bool=false,
vector::Array{<:Any,1}=issing, missing, missing],
vector_unit::Symbol = :km_s,
vector_name::String = "velocity",
vector_log10::Bool=false,
positions_unit::Symbol = :standard,
chunk_size::Int = 50000,
compress::Bool = false,
max_particles::Int = 100_000_000,
verbose::Bool = true,
myargs::ArgumentsType=ArgumentsType()
)
Arguments
---------
Required:
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• **dataobject::PartDataType:*** needs to be of type "PartDataType"
• outprefix: The base path and prefix for output file (e.g.,
"foldername/particles" will create "foldername/particles.vtu").
Predefined/Optional Keywords:
⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅
• scalars: List of scalar variables to export (default is particle
mass); from the database or a predefined quantity (see field:
info, function getvar(), dataobject.data)
• scalars_unit: Sets the unit for the list of scalars (default is
Msun).
• scalars_log10: Apply log10 to the scalars (default false).
• vector: List of vector component variables to export (default is
missing).
• vector_unit: Sets the unit for the vector components (default is
km/s).
• vector_name: The name of the vector field in the VTK file
(default: "velocity").
• vector_log10: Apply log10 to the vector components (default:
false).
• positions_unit: Sets the unit of the particle positions (default:
code units); usefull in paraview to select regions
• chunk_size::Int = 50000: Size of data chunks for processing
(reserved for future optimizations).
• compress: If false (default), disable compression.
• max_particles: Maximum number of particles to export (caps output
if exceeded), (default: 100000000)
• verbose: If true (default), print detailed progress and diagnostic
messages.