releases.rst

Release notes

These notes document the changes between individual GLASS releases.

2024.1 (16 Jul 2024)

• Further changes to the :func:`~glass.shells.partition()` function.
  • The output of partition() now has the shells axis as its first. This means that the new output is the transpose of the previous output.
  • A new partition(..., method="nnls") method that computes a partition with non-negative contributions for each shell. This is now the default. The "nnls" method works much better than "lstsq" since it does not introduce small negative densities, and should almost always be preferred.
  • Both partition(method="nnls") and partition(method="lstsq") now have an additional integral constraint so that the sum of the partition recovers the integral of the input function.
  • The partition() function now works correctly with functions having extra axes.
• A new function :func:`~glass.shells.combine()` that evaluates the linear combination of radial window functions with given weights. This function is the inverse of :func:`~glass.shells.partition()` and can be used to obtain the effect of the discretisation on, e.g., a redshift distribution.
• There is now a way to compute the effective angular power spectra that can be expected from a GLASS simulation, including all discretisations and approximations.
  • A new function :func:`~glass.fields.effective_cls()` which combines power spectra using a list of weights. This function essentially models the linear combinations that happen in the simulation.
  • A new function :func:`~glass.points.position_weights()` that returns weights for effective_cls() to model the result of :func:`~glass.points.positions_from_delta()`.
  • A new function :func:`~glass.lensing.multi_plane_weights()` that returns weights for effective_cls() to model the result of :class:`~glass.lensing.MultiPlaneConvergence`.
• A new function :func:`~glass.galaxies.redshifts()` to sample redshifts following a radial window function. This should always be preferred to the existing :func:`~glass.galaxies.redshifts_from_nz()` function, since the redshift distribution entering the two-point statistics is in fact fixed by the window functions.

2023.7 (1 Aug 2023)

• New radial window functions :func:`~glass.shells.linear_windows()` and :func:`~glass.shells.cubic_windows()`, which correspond to linear and cubic spline interpolation of radial functions, respectively. These are overlapping window functions, and it has been difficult to obtain accurate matter power spectra so far.

• The :func:`~glass.shells.partition()` function now returns an array of weights to approximate a given function by the window functions. This is necessary to obtain an accurate fit of redshift distributions by overlapping window functions. For example, to get the array of galaxy densities in each shells from dndz, one would now do:

  ngal = partition(z, dndz, shells)
  

• A new function :func:`~glass.fields.getcl()` was added to return angular power spectra by index from a list using GLASS ordering.

• The :func:`~glass.galaxies.gaussian_phz()` function now accepts bounds using lower= and upper= keyword parameters.

2023.6 (30 Jun 2023)

• There is some support for simulating the deflections due to weak gravitational lensing:
  • The :func:`~glass.lensing.deflect` function applies deflections to positions.
  • The :func:`~glass.lensing.from_convergence` function returns one or more other lensing fields given the convergence.
  • The shear_from_convergence() function is deprecated in favour of from_convergence().
• The glass module is no longer a namespace package. The new glass.ext namespace is reserved for extensions instead. This is done to follow best practices, so that a bad extension can no longer break all of GLASS by mistake. The glass.all meta-module is no longer necessary.
• The point sampling functions :func:`~glass.points.positions_from_delta` and :func:`~glass.points.uniform_positions` now return an iterator over points. This has lead to orders-of-magnitude improvements in memory use and performance when simulating galaxies at Euclid/LSST densities.
• The ellipticity sampling functions :func:`~glass.shapes.ellipticity_gaussian` and :func:`~glass.shapes.ellipticity_intnorm` accept array inputs.
• A bug causing incorrect results from :func:`~glass.points.effective_bias` has been fixed.

2023.5 (31 May 2023)

• The point sampling functions in :mod:`glass.points` now accept extra dimensions, and will broadcast leading axes across their inputs. They also return an additional scalar or array with the counts of sampled galaxies.
• The redshift sampling function :func:`glass.galaxies.redshifts_from_nz` now supports array input for the counts argument. It accepts e.g. the number of galaxies returned by the position sampling.
• The profiling functionality in :mod:`glass.user` was removed in favour of external packages.

2023.2 (1 Mar 2023)

• New user functions :func:`glass.user.save_cls` and :func:`glass.user.load_cls` to save and load angular power spectra in the GLASS format.
• Some type hints were added to library functions. These are mostly perfunctory at this time, but there is interest in adding proper typing support in the future, including use of the Array API.
• The glass.matter module was removed in favour of the more appropriately-named :mod:`glass.shells` module for shell definitions.
• Instead of using an array of shell boundaries and separate MatterWeights, shells are now entirely defined by a :class:`glass.shells.RadialWindow` window function.
• Many functions have an improved interface thanks to the previous point:
  • The glass.math.restrict_interval function has been replaced by :func:`glass.shells.restrict`, as shells are now defined by window functions instead of sharp intervals.
  • The :func:`glass.points.effective_bias` function now takes a window function as input and computes its effective bias parameter.
  • The glass.galaxies.constant_densities and density_from_dndz functions have been removed, since densities can now easily be partitioned by window functions using :func:`glass.shells.restrict` and :func:`glass.shells.partition`.
  • The zmin and zmax parameters of glass.galaxies.redshifts_from_nz have been removed for the same reason.
  • The glass.lensing.multi_plane_weights function, which computed all lensing weights at once, is replaced by the add_window method of :class:`glass.lensing.MultiPlaneConvergence`, which adds a convergence plane given by a :class:`~glass.shells.RadialWindow` at its effective redshift.
  • The :func:`glass.lensing.multi_plane_matrix` function now takes a sequence of :class:`~glass.shells.RadialWindow`. It no longer returns the list of source redshifts, since these are now independently available as the effective redshifts of the windows.
• The arguments of the :class:`~glass.lensing.MultiPlaneConvergence` method add_plane have been renamed to zsrc and wlens from the more ambiguous z and w (which could be confused with "window"). The properties z and w that returned these values have been similarly changed.

2023.1 (31 Jan 2023)

• Initial wide release for GLASS paper

  This was the initial full release of GLASS, coinciding with the release of preprint arXiv:2302.01942.