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,
    get_weight_factor, flag_to_weight_array,
    FlagContext, VisSelection, io::{read_mwalib, write_uvfits}
};
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(
    flag_array.view_mut(),
    &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
read_mwalib(&vis_sel, &corr_ctx, jones_array.view_mut(), flag_array.view_mut(), false)
    .unwrap();

// write the flags to disk as .mwaf
write_flags(flag_template.to_str().unwrap(),
            &corr_ctx,
            &vis_sel,
            flag_array.view(),
            true,
            None,
            None,
).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,
).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 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 preprocessing::PreprocessContext;
pub use van_vleck::correct_van_vleck;
pub use cli::BirliContext;
pub use marlu;
pub use marlu::mwalib;
pub use marlu::mwalib::fitsio;
pub use marlu::mwalib::fitsio_sys;
pub use marlu::ndarray;

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
van_vleck: Van Vleck corrections for MWA data.

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: This represents the basic metadata and methods for an MWA correlator observation.
Jones
VisSelection: Keep track of which mwalib indices the values in a jones array, its’ weights and its’ flags came from. Similar to a VisContext, but requires an mwalib::CorrelatorContext to be fully interpreted

Enums§

BirliError: An enum of all the errors possible in Birli

Traits§

IndexedParallelIterator: An iterator that supports “random access” to its data, meaning that you can split it at arbitrary indices and draw data from those points.
IntoParallelIterator: IntoParallelIterator implements the conversion to a ParallelIterator.
IntoParallelRefIterator: IntoParallelRefIterator implements the conversion to a ParallelIterator, providing shared references to the data.
IntoParallelRefMutIterator: IntoParallelRefMutIterator implements the conversion to a ParallelIterator, providing mutable references to the data.
ParallelIterator: Parallel version of the standard iterator trait.

Functions§

get_durations: Get the hashmap of durations used internally by Birli for timing functions with with_increment_duration!

Type Aliases§

Array3: three-dimensional array

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