Sherpa 4.11.0 release (rather belated)

Sherpa 4.11.0 has been release for quite some time now, what with a release date of 20 February 2019, and I obviously only just noticed as I came to write the 4.11.1 release blog. Oops. Anyway,on with the show: Sherpa is available via our Conda channel (https://conda.anaconda.org/sherpa/), pip (https://pypi.python.org/pypi/sherpa/4.11.0), Zenodo (https://zenodo.org/record/2573885), and GitHub (https://github.com/sherpa/sherpa/tree/4.11.0).

We thank everyone who contributed to this release with feature requests, bug reports, testing, code contributions, questions, cookies, and any other positive interaction. Please join in the fun on GitHub: https://github.com/sherpa/sherpa

The documentation for this release can be found at https://sherpa.readthedocs.io/en/4.11.0/

OVERVIEW

Optimization routines and statistic methods were made more robust with several bug fixes and improvements.

This version of Sherpa has been tested with Python 2.7, 3.5, 3.6, and 3.7. Support for Python 2.7 is deprecated and will be dropped in a future release.

This release also provides support for XSPEC 12.10.1 (patch 'a' or later) in addition to versions 12.10.0 (included in CIAO 4.11.0) and version 12.9.1.

Details

Documentation and infrastructure fixes are not shown.

#444 Improve caching

When fitting multiple datasets simultaneously Sherpa now tries to cache
model evaluations to improve performance.

#465 Support XSPEC 12.10.0 (fix #436)

XSPEC 12.10.0e is now supported

#508 Ensure fields are initialized before use (pileup code)

Resolved an issue where some fields in the C++ extension could have been
uninitialized in a corner case.

#523 Ensure the ui modules have a unique list of exported symbols (fix #502)

Remove the sherpa.utils.erf symbol from the two ui modules as it is
"over-written" by the ModelWrapper-created symbol when applied to
sherpa.models.basic.Erf.

#524 Be explicit about 'invalid escape characters' in strings

Convert strings that contain "invalid" escape characters, which newer
versions of Python complain about, to raw strings by preceding them with a 'r'
character.

#525 Fixed based line radpro_dm test and changed double --> real (template)

#530 Ensure XSPEC 12.10.0 uses ATOMDB 3.0.9 by default

Ensure that the default AtomDB version is 3.0.9 when using XSPEC 12.10.0.
This is to fix an issue with the models-only XSPEC installation in XSPEC
12.10.0 which uses a default version of 3.0.7 but only provides data files for
3.0.9. Without this change models such as XSapec would return all 0's (unless
the AtomDB version was set manually by the user).

#534 XSPEC 12.10.1 support and mtable fix

Sherpa now supports XSPEC 12.10.1. Several issues were fixed to ensure
compatibility with this release. Note that there are known issues with version
12.10.1 (no patches), so at least v12.10.1a must be used.

#537 / #552 sherpa.rc changes

Sherpa does not read the verbosity.level setting from sherpa.rc anymore but
the option is still in the file for backward compatibility

#539 Fix XSPEC models: mtable table models and ismabs (fix #535, #538, #540)

Fix to address issues with XSpec- #535 XSPEC multiplicative table models
(mtable models loaded with load_xstable_model); #538 incorrect evaluation of
the ismabs model; #540 the kerrd model evaluated to 0 for XSPEC 12.10.0 and
later.

#546 Small code cleanup in LevMar

small code cleanup in the LevMar class to match the other classes in that
file.

#564 / #567 Harmonise the handling of dof is zero or negative in fit and calc_stat_info (fix #565)

The fit and calc_stat_info methods now use the same code to calculate
the reduced statistic (rstat) and "quality of fit" (qval) values. This
avoids a TypeError when the number of degrees of freedom is negative in
calc_stat_info and ensures that NaN is returned for both values when the
goodness-of-fit calculation has failed (e.g. the reduced statistic is zero or
less or the statistic is negative), whereas in previous versions the qval
value could be None or 1 depending on the code path.

#576 Fix regression with responses get_x method

Version 4.10.1 introduced a regression which made the get_x() method fail
when called on RMF and ARF objects. This has been resolved.

#583 Update pager code (fix #445 #561)

Replace the use of an external pager (such as more or less) with a
Python one. This means that Sherpa no-longer uses the PAGER environment
variable, and that the screen output from the show_* series of commands
should now appear in the correct location when using a Jupyter notebook or the
spyder application.