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Next: Class Structures Up: NOTE 216 - Lattice Expression Language Implementation Previous: NOTE 216 - Lattice Expression Language Implementation

Introduction

The Lattice Expression Language (just a fancy name for some C++ classes !) allows manipulation of mathematical expressions involving Lattices directly from C++. The Lattices involved in the expressions are iterated through tile by tile, and the expression evaluated for each pixel in the tiles. Thus there are no large temporary Lattices, and the iteration is efficient.

LEL offers many of the standard numerical and logical operators and functions (that can be applied to scalars and Arrays), as well as some additional astronomically oriented ones. It can handle Float, Double, Complex and DComplex Lattices, including expressions involving mixtures of these types of Lattices. Conversion of data types is automatic, although the user can also embed explicit conversions.

The user can build expressions from subexpressions, finally evaluating the final expression.

Throughout this document we will refer to objects of class Lattice. In reality, this is an abstract class and the real objects would be derived from it.

Next: Class Structures Up: NOTE 216 - Lattice Expression Language Implementation Previous: NOTE 216 - Lattice Expression Language Implementation