Francois Brun / gammalib

… including docs and unit tests

  - New naming scheme.
  - New utility functions/constructor supporting cutoff-energy.
  - Usage of new helper functions for xml read-in/write-out.

The GModelSpectralRegistry::alloc() method now also checks for the existence of model parameters and allocates the appropriate model from the registry that is found in the XML file base on model type and parameter names. This allows now to have the same model type but different parameter names in the registry.

The spectral model classes have been adapted to the new logic, and models have been added to the registry for all parameter combinations that may exist.

The unit tests and documentation have been updated.

Remove the m_names members from the spatial, spectral and temporal registry classes and directly use the model type to find the appropriate model. The alloc() method now throws an exception if the model is not found. The new logic helped to reduced the code in the client classes (#1824)

This is in anticipate of the model name changes in release 1.2

This is an anticipation of the renaming of the spectral models that will come in release 1.2.

It seems better to not introduce the alias method but to use a type constructor instead. This allows writing out the same model type that was read in, enhancing the compatibility with the legacy XML format.

The following new names have been introduced for the spatial model components:
* "PointSource" (alias: "SkyDirFunction")
* "RadialDisk" (alias: "DiskFunction")
* "RadialGaussian" (alias: "GaussFunction")
* "RadialShell" (alias: "ShellFunction")
* "EllipticalDisk"
* "EllipticalGaussian" (alias: "EllipticalGauss")
* "DiffuseIsotropic" (alias: "ConstantValue")
* "DiffuseMap" (alias: "SpatialMap")
* "DiffuseMapCube" (alias: "MapCubeFunction")

There are machine dependent differences in the computation of solid angles, related to the system dependent precision of trigonometric functions. To avoid errors on the large variety of systems, the required precision for the unit test has been reduced.

The GModel::is_valid() method now allows specifying empty strings for the instrument and id parameters that will skip the specific model validity check. This allows to check for models of a given identifier whatever the instrument, or for models for a given instrument, whatever the identifier.

The normalize attribute provides control over whether a map should be normalize or not. By default a map will be normalize to that the spectral model provides the correct fluxes, but for some specific analyses, normalization can now be switched off by adding normalize="0" in the XML file. The attribute has also be added as optional argument to the constructors. A unit test has been added that checks the functionnality.

The GModelSpectralSuperExpPlaw code has been reviewed for integration into the development tree. Most changes were related to code formatting, some changes were needed in the XML interface to correctly reflect the model type "PLSuperExpCutoff".

A unit test method has been added to test_GModel, modelled on unit tests for other spectral models.