Change log Library_lattices_Lattices for AIPS++ version 1.9

A summary of the changes is available.

Change-id:  0160
Author:     Ger van Diepen
Date:       2003/12/24
Area:       Library  lattices    Lattices
Category:   New Code
Summary:    Added operators like +=

Operators +=, -=, *= and /= have been added to the Lattice classes. In this way it is easier to add another lattice to a lattice. In the old days one could only do it as: lattice.copyData (LatticeExpr(lattice+otherlattice)); Now it can be done as: lattice += otherlattice; which will be faster than the old way. Of course, otherlattice can be any lattice type (thus ranging from an ArrayLattice to an Image to an ImageExpr). In case otherlattice is a LatticeExpr, its value can also be a scalar. It makes it possible to add a scalar to a lattice as: lattice += LatticeExpr(scalar);

Change-id:  0157
Author:     Ger van Diepen
Date:       2003/11/10
Area:       Library  lattices    Lattices
Category:   New Code
Summary:    Added RO_MaskedLatticeIterator

The RO_MaskedLatticeIterator class has been added to the system to iterate through any MaskedLattice in an easy way. Using this new class is slighty more convenient than using RO_LatticeIterator with a getMaskSlice to get the mask. More important is that the performance of MaskedLatticeIterator is much better, especially if the underlying MaskedLattice is a LatticeExpr. It is discussed in more detail in the header file.