Struct Beam 

pub struct Beam { /* private fields */ }

A 2D elliptical Gaussian beam in FITS conventions: FWHM axes in degrees (BMAJ, BMIN) and position angle in degrees East of North (BPA).

use convolve_rs::Beam;

let beam = Beam::from_arcsec(20.0, 10.0, 45.0)?;
assert_eq!(beam.major_arcsec(), 20.0);
assert_eq!(beam.major_deg(), 20.0 / 3600.0);

Implementations

impl Beam

pub fn new( major_deg: f64, minor_deg: f64, pa_deg: f64, ) -> Result<Self, BeamError>

A beam from FWHM axes in degrees and a PA in degrees East of North.

Errors

If a value is not finite, an axis is negative, or minor_deg > major_deg.

use convolve_rs::Beam;

let beam = Beam::new(20.0 / 3600.0, 10.0 / 3600.0, 45.0)?;
assert_eq!(beam.pa_deg(), 45.0);
assert!(Beam::new(10.0 / 3600.0, 20.0 / 3600.0, 0.0).is_err());

pub fn from_arcsec( major_arcsec: f64, minor_arcsec: f64, pa_deg: f64, ) -> Result<Self, BeamError>

A beam from FWHM axes in arcseconds and a PA in degrees East of North.

use convolve_rs::Beam;

let beam = Beam::from_arcsec(20.0, 10.0, 45.0)?;
assert_eq!(beam.minor_deg(), 10.0 / 3600.0);

pub fn zero() -> Self

The zero-size beam, used for masked channels.

pub fn major_deg(&self) -> f64

pub fn minor_deg(&self) -> f64

pub fn pa_deg(&self) -> f64

pub fn major_arcsec(&self) -> f64

pub fn minor_arcsec(&self) -> f64

pub fn has_area(&self) -> bool

True if both axes are positive, so the beam can be convolved.

pub fn is_zero(&self) -> bool

pub fn is_circular(&self, rtol: f64) -> bool

pub fn area_sr(&self) -> f64

Solid angle in steradians.

pub fn deconvolve(&self, other: &Beam) -> Result<Beam, BeamError>

The beam that, convolved with other, gives self.

Errors

BeamError::DeconvolveFailed if the result would not be a beam with positive area, as in radio_beam.

use convolve_rs::Beam;

let a = Beam::from_arcsec(10.0, 8.0, 30.0)?;
let b = Beam::from_arcsec(6.0, 5.0, 15.0)?;
let recovered = a.convolve(&b).deconvolve(&a)?;
assert!((recovered.major_arcsec() - b.major_arcsec()).abs() < 1e-6);
assert!((recovered.minor_arcsec() - b.minor_arcsec()).abs() < 1e-6);
assert!(b.deconvolve(&a).is_err());

pub fn deconvolve_or_zero(&self, other: &Beam) -> Beam

Like Beam::deconvolve, but a zero beam on failure.

pub fn contains(&self, other: &Beam) -> bool

True if other can be convolved up to self.

Unlike Beam::deconvolve, this accepts a kernel that is a line or a point (e.g. 20″×10″ inside 20″×20″), which the UV-plane filter handles.

use convolve_rs::Beam;

let target = Beam::from_arcsec(20.0, 20.0, 0.0)?;
assert!(target.contains(&Beam::from_arcsec(20.0, 10.0, 0.0)?));
assert!(!target.contains(&Beam::from_arcsec(21.0, 10.0, 0.0)?));

pub fn convolve(&self, other: &Beam) -> Beam

The convolution of two beams.

use convolve_rs::Beam;

let a = Beam::from_arcsec(3.0, 3.0, 0.0)?;
let b = Beam::from_arcsec(4.0, 4.0, 0.0)?;
assert!((a.convolve(&b).major_arcsec() - 5.0).abs() < 1e-9);

pub fn approx_eq(&self, other: &Beam) -> bool

Equal axes to within 1e-10 degrees, and equal PA (mod 180°) unless the beam is circular.

Trait Implementations

impl Clone for Beam

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Beam

impl Debug for Beam

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Beam

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.