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casa::LELFunctionFloat Class Reference

This LEL class handles numerical functions whose return type is a Float. More...

#include <LELFunction.h>

Inheritance diagram for casa::LELFunctionFloat:
casa::LELInterface< Float >

List of all members.

Public Member Functions

 LELFunctionFloat (const LELFunctionEnums::Function function, const Block< LatticeExprNode > &expr)
 Constructor takes operation and left and right expressions to be operated upon.
 ~LELFunctionFloat ()
 Destructor.
virtual void eval (LELArray< Float > &result, const Slicer &section) const
 Recursively evaluate the expression.
virtual LELScalar< FloatgetScalar () const
 Recursively evaluate the scalar expression.
virtual Bool prepareScalarExpr ()
 Do further preparations (e.g.
virtual String className () const
 Get class name.
virtual Bool lock (FileLocker::LockType, uInt nattempts)
 Handle locking/syncing of a lattice in a lattice expression.
virtual void unlock ()
virtual Bool hasLock (FileLocker::LockType) const
virtual void resync ()

Private Attributes

LELFunctionEnums::Function function_p
 
   

Block< LatticeExprNodearg_p

Detailed Description

This LEL class handles numerical functions whose return type is a Float.

Intended use:

Internal

Review Status

Date Reviewed:
yyyy/mm/dd

Prerequisite

Etymology

This derived LEL letter class handles numerical functions (arbitrary number of arguments) which return a Float

Synopsis

This LEL letter class is derived from LELInterface. It is used to construct LEL objects that apply numerical functions of arbitrary number of arguments (but only 1 or 2 arguments currently implemented) to Lattice expressions. They operate on Float or Complex Lattices and return a Float. The available C++ functions are min,max,pow,atan2,fmod,abs,arg,real,imag with equivalents in the enum of MIN,MAX,POW,ATAN2,FMOD,ABS,ARG,REAL, and IMAG.

A description of the implementation details of the LEL classes can be found in Note 216

Example

Examples are not very useful as the user would never use these classes directly. Look in LatticeExprNode.cc to see how it invokes these classes. Examples of how the user would indirectly use this class (through the envelope) are:

    IPosition shape(2,5,10);
    ArrayLattice<Complex> w(shape); w.set(Complex(2.0,3.0));
    ArrayLattice<Float> x(shape); x.set(0.05);
    ArrayLattice<Float> y(shape); y.set(2.0);
    ArrayLattice<Float> z(shape); y.set(2.0);
   
    z.copyData(min(x,y));                // z = min(x,y)
    z.copyData(imag(w));                 // z = imag(w)

Note that this min function takes two arguments and returns the minimum of the two, pixel by pixel (i.e. it does not return one scalar from the whole Lattice) b

Motivation

Numerical functions are a basic mathematical expression.

Definition at line 418 of file LELFunction.h.


Constructor & Destructor Documentation

Constructor takes operation and left and right expressions to be operated upon.

Destructor.


Member Function Documentation

virtual String casa::LELFunctionFloat::className ( ) const [virtual]

Get class name.

Implements casa::LELInterface< Float >.

virtual void casa::LELFunctionFloat::eval ( LELArray< Float > &  result,
const Slicer section 
) const [virtual]

Recursively evaluate the expression.

Implements casa::LELInterface< Float >.

virtual LELScalar<Float> casa::LELFunctionFloat::getScalar ( ) const [virtual]

Recursively evaluate the scalar expression.

Implements casa::LELInterface< Float >.

Reimplemented from casa::LELInterface< Float >.

virtual Bool casa::LELFunctionFloat::lock ( FileLocker::LockType  ,
uInt  nattempts 
) [virtual]

Handle locking/syncing of a lattice in a lattice expression.

Reimplemented from casa::LELInterface< Float >.

Do further preparations (e.g.

optimization) on the expression.

Implements casa::LELInterface< Float >.

virtual void casa::LELFunctionFloat::resync ( ) [virtual]

Reimplemented from casa::LELInterface< Float >.

virtual void casa::LELFunctionFloat::unlock ( ) [virtual]

Reimplemented from casa::LELInterface< Float >.


Member Data Documentation

Definition at line 453 of file LELFunction.h.

   

Definition at line 452 of file LELFunction.h.


The documentation for this class was generated from the following file: