xspec 12.6 released

HEAsoft 6.9 is out including xspec v12.6. The release notes are below.

One point to note is that there have been internal changes to the models using the Magzdiarz & Zdziarski Compton reflection code. If there are local models out there which use internals from the xspec models they may break. Let us know and we will fix them.

New features in v12.6.0:

The main improvements in version 12.6.0 are to XSPEC's plotting capabilities:

 - Multi-panel plotting is now supported for all combinations except
   contour plots.  For example, "plot data model resid ratio" will
   produce a 4-panel plot on a single page. Up to 6 panels can be
   plotted in this manner.

 - There are many choices for axis units.  These can be selected
   using the "setplot energy" and "setplot wave" commands. For
   example, "setplot energy GeV" uses GeV on the x- and y-axes.
   "setplot wave" also has a new "perhz" option for displaying
   the Y-axis in 1/Hz units.
  
 - The "setplot" command has a new "redshift " option for shifting
   displayed energies to the source frame.
  
Other new features:

 - New models :
      ireflect is a convolution model based on the pexriv code.
      sirf is a multiblackbody self-irradiated funnel

 - The normalizations on all power-law models (ie. powerlaw,
   bknpow, bkn2pow, cutoffpl)can be changed to a flux over an
   energy range by setting POW_EMIN and POW_EMAX keywords in "xset".
   The powerlaw model then becomes equivalent to the pegpwlw model.

 - The Compton reflection models (b/p)exr(a/i)v and (i)reflect have
   been restructured to use adaptive Gauss-Kronrod quadrature for
   the Greens' function integrals. The precision to which the
   integrals are calculated can be set allowing a trade-off between
   speed and precision.
  
 - The wrapper functions additiveTable and multiplicativeTable
   give external C++ models access to XSPEC's table model interpolation
   routines (equivalent to the xsatbl and xsmtbl functions for Fortran
   models).

-  The display of link expressions has been simplified to show only the
   parameter numbers and not the extraneous component information.
   Also "show model" will now only display the model components and
   not the individual parameters.  The parameters can be seen with
   "show par". 

Additional enhancements previously released as patches to 12.5.1:

 - Added the solar abundance data set of Asplund, Grevesse, and Sauval
   (2006) to the list of available tables accessed with the "abund"
   command.
  
 - New "tclout nchan" option for returning the number of channels in a
   spectrum.
  
 - The "save" command now stores relative rather than absolute paths to
   allow easier porting to other machines.
  
 - The recorn model component has been converted from a mixing to a
   multiplicative type.  This allows a model to define multiple recorn
   components.

 - A warning message is now issued if a user attempts to load a
   response for a source n when there are still slots to fill for
   source n-1.  This is intended to catch cases where a user mistakenly
   reverses the source and spectrum number input to the "response"
   command.
  
All bug fixes to v12.5.1 released as patches a - o are included in
v12.6.0.  In addition the following problems have been corrected:

 - It was possible for the addition of a systematic model error to
   actually decrease the overall variance, when it was applied to a
   zero-variance bin that was artificially increased by XSPEC for chi-
   square fitting.
  
 - Bug in "plot ratio" when using "setplot wave" with Hz units.  Y-axis
   model values < 10^-20 were not displayed in plot.
  
 - The comptt model no longer stops and prompts the user when it fails
   during its incomplete gamma calculation.
  
 - The powerlaw model has been modified to avoid a numerical
   instability that could occur if the index were within 10^-12 to
   10^-15 of 1.0.