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casacore::ImageExprParse Class Reference

Class to hold values from image expression parser. More...

#include <ImageExprParse.h>

Public Member Functions

 ImageExprParse (Bool value)
 Construct a literal object for the given type. More...
 
 ImageExprParse (Int value)
 
 ImageExprParse (Float value)
 
 ImageExprParse (Double value)
 
 ImageExprParse (const Complex &value)
 
 ImageExprParse (const DComplex &value)
 
 ImageExprParse (const Char *value)
 
 ImageExprParse (const String &value)
 
LatticeExprNode makeFuncNode () const
 Make a LatticeExprNode for a function. More...
 
LatticeExprNode makeFuncNode (const LatticeExprNode &arg1) const
 
LatticeExprNode makeFuncNode (const LatticeExprNode &arg1, const LatticeExprNode &arg2) const
 
LatticeExprNode makeFuncNode (const LatticeExprNode &arg1, const LatticeExprNode &arg2, const LatticeExprNode &arg3) const
 
LatticeExprNode makeLRNode () const
 Make a LatticeExprNode object for the lattice or region name. More...
 
LatticeExprNode makeLitLRNode () const
 Make a LatticeExprNode object for the name of constant, lattice, or region. More...
 
LatticeExprNode makeRegionNode () const
 Make a LatticeExprNode object for the temporary region number. More...
 
LatticeExprNode makeLiteralNode () const
 Make a LatticeExprNode object for the literal value. More...
 

Static Public Member Functions

static LatticeExprNode command (const String &str, const String &dirName=String())
 Parse the given command. More...
 
static LatticeExprNode command (const String &str, const Block< LatticeExprNode > &tempLattices, const PtrBlock< const ImageRegion * > &tempRegions, const String &dirName=String())
 
static SlicemakeSlice (const ImageExprParse &start)
 Make a Slice object from 1-3 literals. More...
 
static SlicemakeSlice (const ImageExprParse &start, const ImageExprParse &end)
 
static SlicemakeSlice (const ImageExprParse &start, const ImageExprParse &end, const ImageExprParse &incr)
 
static LatticeExprNode makeIndexinNode (const LatticeExprNode &axis, const vector< Slice > &slices)
 Make a node for the INDEXIN function. More...
 
static LatticeExprNode makeValueList (const Block< LatticeExprNode > &values)
 Make an array from a value list. More...
 
static IPosition makeBinning (const LatticeExprNode &values)
 Make an IPosition containing the binning values. More...
 
static const vector< String > & getImageNames ()
 Get the names of the images used in the expression. More...
 
static void setNode (const LatticeExprNode &node)
 Set the static node object (used by the.y file). More...
 
static void addNode (LatticeExprNode *node)
 Keep track of the nodes allocated while parsing the expression. More...
 
static void addNode (ImageExprParse *node)
 
static void deleteNodes ()
 
static String setAddDir (const String &dirName, const String &fileName)
 A function to test addDir. More...
 

Private Member Functions

Bool tryLatticeNode (LatticeExprNode &node, const String &name) const
 Try if the name represent a lattice or image. More...
 
LatticeExprNode makeImageNode (const String &name, const String &mask) const
 Make the node from the image name and a mask name. More...
 

Static Private Member Functions

static String addDir (const String &fileName)
 If a directory was given, prepend it to the file name if relative. More...
 
static TablegetRegionTable (void *, Bool)
 Callback function for RegionHandlerTable to get the table to be used. More...
 
static const CountedPtr
< HDF5File > & 
getRegionHDF5 (void *)
 Callback function for RegionHandlerHDF5 to get the file to be used. More...
 

Private Attributes

DataType itsType
 
Bool itsBval
 
Int itsIval
 
Float itsFval
 
Double itsDval
 
Complex itsCval
 
DComplex itsDCval
 
String itsSval
 

Static Private Attributes

static LatticeExprNode theirNode
 
static vector< StringtheirNames
 
static Int theirLevel
 

Detailed Description

Class to hold values from image expression parser.

Intended use:

Public interface

Prerequisite

Etymology

ImageExprParse is the class used to parse an image expression command.

Synopsis

ImageExprParse is used by the parser of image expression statements. The parser is written in Bison and Flex in files ImageExprGram.y and.l. The statements in there use the routines in this file to act upon a reduced rule.

The main function (and the only function to be used by a user) is the static function ImageExprParse::command which parses an expression command. It returns a LatticeExprNode object containing the expression represented as a tree. The object can be used as a Lattice(Expr)<T> in other operations.

The syntax of the command is similar to that of expressions in C++. E.g.

min(img1, img2) + sin(img3)

The following items can be used in an expression:

When the expression is parsed, it is checked if the images and lattices involved have conforming shapes and coordinates. Note, however, that some functions (e.g. mean) reduce an image to a scalar. Such an image can have a different shape and coordinates.

The data types of the images and constants involved can be different. The data type of a subexpression is the common data type (e.g. Float and Double result in Double; Complex and Double result in DComplex). Automatic implicit conversions are done where needed. However, for performance reasons it may sometimes be better to convert explicitly. See below in the first example.

The expression evaluator (which is not part of the parser) evaluates the expression in chunks to avoid having to keep large temporary results. A scalar subexpression is evaluated only once to avoid unnecessary (possibly expensive) calculations.

Some examples:

img1 + min(float(pi()), mean(img2))
Suppose img1 and img2 are images with single precision data. They do not need to have conforming shapes and coordinates, because only the mean of img2 is used.
Note that pi is explicitly converted to single precision, because pi() results in a Double. If that was not done, the expression result would be a Double with the effect that all data of img1 had to be converted to Double.
min(img1, (min(img1)+max(img1))/2)
This example shows that there are 2 min functions. One with a single argument returning the minimum value of that image. The other with 2 arguments returning a lattice containing img1 data clipped at the value of the 2nd argument.

Example

LatticeExpr<Double> expr ("a + sin(b)");
ArrayLattice<Double> arr(expr.shape());
arr.copyData (expr);

Line 1 creates a LatticeExpr object for the given expression. Note that a and b are names of lattice files (e.g. PagedImage).
Line 2 creates an ArrayLattice with the same shape as the expression (which is the shape of lattice a (and b)).
Line 3 copies the result of the expression to the ArrayLattice.

Motivation

It is necessary to be able to give an image expression command in ASCII. This can be used in glish to operate on lattices/images.

Definition at line 205 of file ImageExprParse.h.

Constructor & Destructor Documentation

casacore::ImageExprParse::ImageExprParse ( Bool  value)

Construct a literal object for the given type.

casacore::ImageExprParse::ImageExprParse ( Int  value)
casacore::ImageExprParse::ImageExprParse ( Float  value)
casacore::ImageExprParse::ImageExprParse ( Double  value)
casacore::ImageExprParse::ImageExprParse ( const Complex &  value)
casacore::ImageExprParse::ImageExprParse ( const DComplex &  value)
casacore::ImageExprParse::ImageExprParse ( const Char value)
casacore::ImageExprParse::ImageExprParse ( const String value)

Member Function Documentation

static String casacore::ImageExprParse::addDir ( const String fileName)
staticprivate

If a directory was given, prepend it to the file name if relative.

static void casacore::ImageExprParse::addNode ( LatticeExprNode node)
static

Keep track of the nodes allocated while parsing the expression.

static void casacore::ImageExprParse::addNode ( ImageExprParse node)
static
static LatticeExprNode casacore::ImageExprParse::command ( const String str,
const String dirName = String() 
)
static

Parse the given command.

It will open all lattices needed. It returns the resulting image expression.
The tempLattices/tempRegions arguments make it possible to use temporary lattices/images and regions in the expression by means of the $n notation.
If a directory name is given, it is used instead of the working directory for relative file names.

static LatticeExprNode casacore::ImageExprParse::command ( const String str,
const Block< LatticeExprNode > &  tempLattices,
const PtrBlock< const ImageRegion * > &  tempRegions,
const String dirName = String() 
)
static
static void casacore::ImageExprParse::deleteNodes ( )
static
static const vector<String>& casacore::ImageExprParse::getImageNames ( )
inlinestatic

Get the names of the images used in the expression.

Definition at line 284 of file ImageExprParse.h.

References theirNames.

static const CountedPtr<HDF5File>& casacore::ImageExprParse::getRegionHDF5 ( void *  )
staticprivate

Callback function for RegionHandlerHDF5 to get the file to be used.

static Table& casacore::ImageExprParse::getRegionTable ( void *  ,
Bool   
)
staticprivate

Callback function for RegionHandlerTable to get the table to be used.

static IPosition casacore::ImageExprParse::makeBinning ( const LatticeExprNode values)
static

Make an IPosition containing the binning values.

LatticeExprNode casacore::ImageExprParse::makeFuncNode ( ) const

Make a LatticeExprNode for a function.

LatticeExprNode casacore::ImageExprParse::makeFuncNode ( const LatticeExprNode arg1) const
LatticeExprNode casacore::ImageExprParse::makeFuncNode ( const LatticeExprNode arg1,
const LatticeExprNode arg2 
) const
LatticeExprNode casacore::ImageExprParse::makeFuncNode ( const LatticeExprNode arg1,
const LatticeExprNode arg2,
const LatticeExprNode arg3 
) const
LatticeExprNode casacore::ImageExprParse::makeImageNode ( const String name,
const String mask 
) const
private

Make the node from the image name and a mask name.

The mask name can be NOMASK (case insensitive) meaning that no mask is applied to the image.

static LatticeExprNode casacore::ImageExprParse::makeIndexinNode ( const LatticeExprNode axis,
const vector< Slice > &  slices 
)
static

Make a node for the INDEXIN function.

LatticeExprNode casacore::ImageExprParse::makeLiteralNode ( ) const

Make a LatticeExprNode object for the literal value.

LatticeExprNode casacore::ImageExprParse::makeLitLRNode ( ) const

Make a LatticeExprNode object for the name of constant, lattice, or region.

LatticeExprNode casacore::ImageExprParse::makeLRNode ( ) const

Make a LatticeExprNode object for the lattice or region name.

LatticeExprNode casacore::ImageExprParse::makeRegionNode ( ) const

Make a LatticeExprNode object for the temporary region number.

static Slice* casacore::ImageExprParse::makeSlice ( const ImageExprParse start)
static

Make a Slice object from 1-3 literals.

static Slice* casacore::ImageExprParse::makeSlice ( const ImageExprParse start,
const ImageExprParse end 
)
static
static Slice* casacore::ImageExprParse::makeSlice ( const ImageExprParse start,
const ImageExprParse end,
const ImageExprParse incr 
)
static
static LatticeExprNode casacore::ImageExprParse::makeValueList ( const Block< LatticeExprNode > &  values)
static

Make an array from a value list.

static String casacore::ImageExprParse::setAddDir ( const String dirName,
const String fileName 
)
static

A function to test addDir.

It first sets the directory.

static void casacore::ImageExprParse::setNode ( const LatticeExprNode node)
inlinestatic

Set the static node object (used by the.y file).

Definition at line 288 of file ImageExprParse.h.

References theirNode.

Bool casacore::ImageExprParse::tryLatticeNode ( LatticeExprNode node,
const String name 
) const
private

Try if the name represent a lattice or image.

Return False if not.

Member Data Documentation

Bool casacore::ImageExprParse::itsBval
private

Definition at line 330 of file ImageExprParse.h.

Complex casacore::ImageExprParse::itsCval
private

Definition at line 334 of file ImageExprParse.h.

DComplex casacore::ImageExprParse::itsDCval
private

Definition at line 335 of file ImageExprParse.h.

Double casacore::ImageExprParse::itsDval
private

Definition at line 333 of file ImageExprParse.h.

Float casacore::ImageExprParse::itsFval
private

Definition at line 332 of file ImageExprParse.h.

Int casacore::ImageExprParse::itsIval
private

Definition at line 331 of file ImageExprParse.h.

String casacore::ImageExprParse::itsSval
private

Definition at line 336 of file ImageExprParse.h.

DataType casacore::ImageExprParse::itsType
private

Definition at line 329 of file ImageExprParse.h.

Int casacore::ImageExprParse::theirLevel
staticprivate

Definition at line 327 of file ImageExprParse.h.

vector<String> casacore::ImageExprParse::theirNames
staticprivate

Definition at line 326 of file ImageExprParse.h.

Referenced by getImageNames().

LatticeExprNode casacore::ImageExprParse::theirNode
staticprivate

Definition at line 322 of file ImageExprParse.h.

Referenced by setNode().


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