Crate birli

Expand description

Birli is a library of common preprocessing tasks performed in the data pipeline of the Murchison Widefield Array (MWA) Telescope.

Examples

Here’s an example of how to flag some visibility files

use birli::{
    write_flags,
    mwalib::CorrelatorContext, write_uvfits,
    get_weight_factor, flag_to_weight_array,
    FlagContext, VisSelection
};
use tempfile::tempdir;

// define our input files
let metafits_path = "tests/data/1297526432_mwax/1297526432.metafits";
let gpufits_paths = vec![
    "tests/data/1297526432_mwax/1297526432_20210216160014_ch117_000.fits",
    "tests/data/1297526432_mwax/1297526432_20210216160014_ch117_001.fits",
    "tests/data/1297526432_mwax/1297526432_20210216160014_ch118_000.fits",
    "tests/data/1297526432_mwax/1297526432_20210216160014_ch118_001.fits",
];

// define a temporary directory for output files
let tmp_dir = tempdir().unwrap();

// define our output paths
let flag_template = tmp_dir.path().join("Flagfile%%%.mwaf");
let uvfits_out = tmp_dir.path().join("1297526432.uvfits");

// Create an mwalib::CorrelatorContext for accessing visibilities.
let corr_ctx = CorrelatorContext::new(&metafits_path, &gpufits_paths).unwrap();

// Determine which timesteps and coarse channels we want to use
let vis_sel = VisSelection::from_mwalib(&corr_ctx).unwrap();

// Prepare our flagmasks with known bad antennae
let flag_ctx = FlagContext::from_mwalib(&corr_ctx);

// Create a blank array to store flags and visibilities
let fine_chans_per_coarse = corr_ctx.metafits_context.num_corr_fine_chans_per_coarse;
let mut flag_array = vis_sel.allocate_flags(fine_chans_per_coarse).unwrap();
flag_ctx.set_flags(
    &mut flag_array,
    &vis_sel.timestep_range,
    &vis_sel.coarse_chan_range,
    &vis_sel.get_ant_pairs(&corr_ctx.metafits_context)
);
let mut jones_array = vis_sel.allocate_jones(fine_chans_per_coarse).unwrap();

// read visibilities out of the gpubox files
vis_sel
    .read_mwalib(&corr_ctx, jones_array.view_mut(), flag_array.view_mut(), false)
    .unwrap();

// write the flags to disk as .mwaf
write_flags(&corr_ctx, &flag_array, flag_template.to_str().unwrap(), &vis_sel.coarse_chan_range).unwrap();
// write the visibilities to disk as .uvfits

let num_pols = corr_ctx.metafits_context.num_visibility_pols;
let weight_factor = get_weight_factor(&corr_ctx);
let weight_array = flag_to_weight_array(&flag_array.view(), weight_factor);
write_uvfits(
    uvfits_out.as_path(),
    &corr_ctx,
    jones_array.view(),
    weight_array.view(),
    &vis_sel.timestep_range,
    &vis_sel.coarse_chan_range,
    &vis_sel.baseline_idxs,
    None,
    None,
    1,
    1,
    false,
).unwrap();

Details

Birli reads visibilities with MWALib and uses CXX to bind to the AOFlagger C++ library. For more details its interface, check out the aoflagger::AOFlagger documentation

Re-exports

pub use io::mwaf::FlagFileSet;

pub use io::write_ms;

pub use io::write_uvfits;

pub use corrections::correct_cable_lengths;

pub use corrections::correct_geometry;

pub use corrections::ScrunchType;

pub use flags::flag_to_weight_array;

pub use flags::get_weight_factor;

pub use flags::write_flags;

pub use flags::FlagContext;

pub use marlu;

pub use marlu::mwalib;

pub use marlu::mwalib::fitsio;

pub use marlu::mwalib::fitsio_sys;

pub use marlu::ndarray;

pub use preprocessing::PreprocessContext;

pub use cli::BirliContext;

pub use flags::flag_jones_array;

pub use flags::flag_jones_array_existing;

Modules

calibration

Calibrating visibilities.

cli

Command Line Interface helpers for Birli

corrections

Corrections that can be performed on visibility data

flags

Methods for manipulating flagmasks and flagging imagesets

io

Input and Ouput data file format modules

passband_gains

Possible choices for polyphase filter bank gains for the MWA.

preprocessing

Crate for preprocessing visibilities

Macros

par_azip

Parallelized array zip macro: lock step function application across several arrays and producers.

with_increment_duration

Time a statement and increment the timer given by name in the hashmap of durations

Structs

Axis

An axis index.

Complex

A complex number in Cartesian form.

CorrelatorContext

mwalib correlator observation context. This represents the basic metadata for a correlator observation.

CxxAOFlagger

CXX Wrapper for aoflagger::AOFlagger, the main class for access to the flagger functionality.

CxxFlagMask

CXX Wrapper for aoflagger::FlagMask, a two-dimensional mask of bool flags.

CxxImageSet

CXX Wrapper for aoflagger::ImageSet, a set of time-frequency ‘images’ which together contain data for one correlated baseline.

Jones

UniquePtr

Binding to C++ std::unique_ptr<T, std::default_delete<T>>.

VisSelection

Keep track of which mwalib indices the values in a jones array, its’ weights and its’ flags came from. Similar to a VisSelection, but requires an mwalib::CorrelatorContext to be fully interpreted