Pierrick Martin / gammalib

…direction into instrument coordinates

These methods provide for a given pointing the SPI X and Y directions

The code now supports loading of IRF information, pre-computation of the IRF array in form of a sky map, and saving the pre-computed IRF to disk.

… of pointing and detector index.

Using these methods avoids initialising parameter gradients that will not be used.

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.

The copying was missing, leading to a core dump.

The GSPIModelDataSpace class implements the INTEGRAL/SPI data space model. The current commit allows already model fitting using the data space model. The various parameter grouping methods are not yet implemented, but the method structure exists already.

The SPI instrument direction is composed of the telescope pointing direction and the detector identifier.

…hods will be in GSPISupport)

…ed computation (#2695)

# Conflicts:
#	ChangeLog
#	NEWS