Release notes

These notes document the changes between individual GLASS releases.

2024.2 (15 Nov 2024)

  • All GLASS user functionality is now available directly from the main glass namespace. No more imports!

  • Changes to the functions dealing with Gaussian spectra:

  • redshifts_from_nz() is deprecated in favour of glass.redshifts(), as the former is almost never the right choice: the two-point statistics in a linear bias model are coming from the shells, so the redshift distribution is implicitly the same as the radial profile of the shells.

  • Several fixes to glass.ellipticity_ryden04().

  • Added a FITS catalogue writer tool glass.write_catalog().

  • Much improved documentation with docstring for all functions.

  • Examples now live in the main GLASS repository and documentation.

  • GLASS is now fully typed and passes mypy.

  • Python 3.13 is now supported. Python 3.8 and NumPy 1.21 are no longer supported.

  • The glass.core.constants module was removed.

2024.1 (16 Jul 2024)

  • Further changes to the 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 combine() that evaluates the linear combination of radial window functions with given weights. This function is the inverse of 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 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 position_weights() that returns weights for effective_cls() to model the result of positions_from_delta().

    • A new function multi_plane_weights() that returns weights for effective_cls() to model the result of MultiPlaneConvergence.

  • A new function redshifts() to sample redshifts following a radial window function. This should always be preferred to the existing 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 linear_windows() and 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 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 getcl() was added to return angular power spectra by index from a list using GLASS ordering.

  • The 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 deflect() function applies deflections to positions.

    • The 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 positions_from_delta() and 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 ellipticity_gaussian() and ellipticity_intnorm() accept array inputs.

  • A bug causing incorrect results from effective_bias() has been fixed.

2023.5 (31 May 2023)

  • The point sampling functions in 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 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 glass.user was removed in favour of external packages.

2023.2 (1 Mar 2023)

  • New user functions glass.user.save_cls() and 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 glass.shells module for shell definitions.

  • Instead of using an array of shell boundaries and separate MatterWeights, shells are now entirely defined by a 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 glass.shells.restrict(), as shells are now defined by window functions instead of sharp intervals.

    • The 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 glass.shells.restrict() and 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 glass.lensing.MultiPlaneConvergence, which adds a convergence plane given by a RadialWindow at its effective redshift.

    • The glass.lensing.multi_plane_matrix() function now takes a sequence of 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 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.