
<change id=0160>
 <author> Ger van Diepen </author>
 <date> 2003/12/24 </date>
 <avers> 1.9 </avers>
 <area> Library </area>
 <package> lattices </package>
 <module> Lattices </module>
 <type> Code </type>
 <category> New </category>
 <defects>  </defects>
 <summary>
Added operators like +=
 </summary>
 <description>
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<T>(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<T>(scalar);
 </description>
</change>

<change id=0073>
 <author> Ger van Diepen </author>
 <date> 2001/02/14 </date>
 <avers> 1.5 </avers>
 <area> Library </area>
 <package> lattices </package>
 <module> Lattices </module>
 <type> Code </type>
 <category> New </category>
 <defects> 1288 </defects>
 <summary>
Fractiles added to LEL
 </summary>
 <description>
The class LatticeFractile has been added.
It contains static functions to find the fractile in a lattice or
to find 2 fractiles simultaneously. Note that the median is the
fractile of 0.5.

It is used in LEL which got the new functions fractile and
fractilerange (see the description in note 223).
 </description>
</change>

<change id=0096>
 <author> Ger van Diepen </author>
 <date> 2001/05/28 </date>
 <avers> 1.6 </avers>
 <area> Library </area>
 <package> lattices </package>
 <module> Lattices </module>
 <type> Code </type>
 <category> New </category>
 <defects>  </defects>
 <summary>
Additions to LEL
 </summary>
 <description>
LEL has been improved in 2 ways:
- 2 new functions have been added.
  isnan can be used to test for NaNs
  spectralindex can be used to calculate the spectral index for 2 images as
     log(s1/s2) / log(f1/f2)

- It can handle images with different dimensionalities. It makes it e.g.
  possible to subtract continuum data from a line cube.
 </description>
</change>

<change id=0157>
 <author> Ger van Diepen </author>
 <date> 2003/11/10 </date>
 <avers> 1.9 </avers>
 <area> Library </area>
 <package> lattices </package>
 <module> Lattices </module>
 <type> Code </type>
 <category> New </category>
 <defects>  </defects>
 <summary>
Added RO_MaskedLatticeIterator
 </summary>
 <description>
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.
 </description>
</change>
