Sergio Hernández Cadena / gammalib

…ead of row-wise access (#3501)

This assures that spatial parameters that are fixed during the model fitting are correctly taken into account.

# Conflicts:
#	src/obs/GObservation.cpp
#	src/obs/GResponse.cpp

…ack for model parameters with analytical gradients at the level of the GObservation class.

…ssian models and stacked analysis (#3203)

Implemented the following methods:
- GVector GModel::eval(GObservation&, GMatrixSparse*)
- GVector GModelSky::eval(GObservation&, GMatrixSparse*)
- GVector GResponse::convolve(GModelSky&, GObservation&, GMatrixSparse*)
- GVector GObservation::model(GModels&, GMatrixSparse*)
- GVector GObservation::model_grad(GModel&, GModelPar&)

The methods GModel::has_eval_indices() and GModel::eval_indices() allow for a more efficient parameter handling in GObservation::model() that is specifically relevant for a model with many parameters, such as the SPI data space models. These methods allow the GModel::eval() method to signal which of the parameters were actually updated, so that the gradients for only these parameters will be considered in GObservation::model(), while all other gradients will be ignored.

# Conflicts:
#	ChangeLog
#	NEWS

…ients argument (#1847)

The eval_gradients() methods duplicate much of the code of the eval() methods. To increase the maintainability of the code, the eval_gradients() methods have been removed, and the computation of partial derivatives is now done by the eval() methods if the optional gradients argument is set to true.

…y intergation is done over all energy ranges in an energy boundary object (see #1450).

Updated at the same time the Doxygen information.