Source Model Bugs: XSpec models

Caveats

1. Version 11.3.1 of the XSpec models is supplied with CIAO 3.4.

2. Using too many XSPEC models in a single session can cause Sherpa to crash.

Bugs

1. In the case of any XSPEC model, or Sherpa model that is not analytically integrable, flux calculation is restricted to the instrument model grid.

2. Sherpa provides the additive and multiplicative model components from XSPEC, but not the mixing model components (e.g. projct).

3. Nesting a model stack "within" an XSPEC model causes a segmentation fault.

Caveats

1. Version 11.3.1 of the XSpec models is supplied with CIAO 3.4.

   The XSpec model functions help file has a list of the available models, as well as a listing of XSpec components which are not included in CIAO 3.4.

2. Using too many XSPEC models in a single session can cause Sherpa to crash.

   This occurred when we used about 80 models in our regression tests:

   Memory Allocation Error: Too many blocks
   Memory Allocation Error: Too many blocks
   Memory Allocation Error: Invalid pointer, can't free memory
   Failed to grab memory in IONSNEQS
   error number =   101
   

   Note that these are messages from the XSPEC library itself; this is not a Sherpa bug.

Bugs

1. In the case of any XSPEC model, or Sherpa model that is not analytically integrable, flux calculation is restricted to the instrument model grid.

2. Sherpa provides the additive and multiplicative model components from XSPEC, but not the mixing model components (e.g. projct).

3. Nesting a model stack "within" an XSPEC model causes a segmentation fault.

   sherpa> foo = const[cs]
   sherpa> source = xsgauss[xg1]{foo}
   sherpa> fit
   Segmentation fault