Epetra_IntVector Class Reference

Epetra_IntVector: A class for constructing and using dense integer vectors on a parallel computer. More...

#include <Epetra_IntVector.h>

Inheritance diagram for Epetra_IntVector:

[legend]Collaboration diagram for Epetra_IntVector:[legend]List of all members.

Public Member Functions
Constructors/destructors.
	Epetra_IntVector (const Epetra_BlockMap &Map, bool zeroOut=true)
	Basic Epetra_IntVector constuctor.
	Epetra_IntVector (const Epetra_IntVector &Source)
	Epetra_IntVector copy constructor.
	Epetra_IntVector (Epetra_DataAccess CV, const Epetra_BlockMap &Map, int *V)
	Set vector values from user array.
virtual	~Epetra_IntVector ()
	Epetra_IntVector destructor.
Post-construction modification methods
int	PutValue (int Value)
	Set all elements of the vector to Value.
Extraction methods
int	ExtractCopy (int *V) const
	Put vector values into user-provided array.
int	ExtractView (int **V) const
	Set user-provided address of V.
Mathematical methods
int	MaxValue ()
	Find maximum value.
int	MinValue ()
	Find minimum value.
Overloaded operators
Epetra_IntVector &	operator= (const Epetra_IntVector &Source)
	= Operator.
int &	operator[] (int index)
	Element access function.
const int &	operator[] (int index) const
	Element access function.
Attribute access functions
int *	Values () const
	Returns a pointer to an array containing the values of this vector.
int	MyLength () const
	Returns the local vector length on the calling processor of vectors in the multi-vector.
int	GlobalLength () const
	Returns the global vector length of vectors in the multi-vector.
I/O methods
virtual void	Print (ostream &os) const
	Print method.

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Detailed Description

Epetra_IntVector: A class for constructing and using dense integer vectors on a parallel computer.

The Epetra_IntVector class enables the construction and use of integer dense vectors in a distributed memory environment. The distribution of the dense vector is determined in part by a Epetra_Comm object and a Epetra_Map (or Epetra_LocalMap or Epetra_BlockMap).

Distributed Global vs. Replicated Local

• Distributed Global Vectors - In most instances, a multi-vector will be partitioned across multiple memory images associated with multiple processors. In this case, there is a unique copy of each element and elements are spread across all processors specified by the Epetra_Comm communicator.
• Replicated Local Vectors - Some algorithms use vectors that are too small to be distributed across all processors. Replicated local vectors handle these types of situation.

Constructing Epetra_IntVectors

There are four Epetra_IntVector constructors. The first is a basic constructor that allocates space and sets all values to zero, the second is a copy constructor. The third and fourth constructors work with user data. These constructors have two data access modes:

1. Copy mode - Allocates memory and makes a copy of the user-provided data. In this case, the user data is not needed after construction.
2. View mode - Creates a "view" of the user data. In this case, the user data is required to remain intact for the life of the vector.

Warning:

View mode is extremely dangerous from a data hiding perspective. Therefore, we strongly encourage users to develop code using Copy mode first and only use the View mode in a secondary optimization phase.

All Epetra_IntVector constructors require a map argument that describes the layout of elements on the parallel machine. Specifically, map is a Epetra_Map, Epetra_LocalMap or Epetra_BlockMap object describing the desired memory layout for the vector.

There are four different Epetra_IntVector constructors:

• Basic - All values are zero.
• Copy - Copy an existing vector.
• Copy from or make view of user int array.

Extracting Data from Epetra_IntVectors

Once a Epetra_IntVector is constructed, it is possible to extract a copy of the values or create a view of them.

Warning:

ExtractView functions are extremely dangerous from a data hiding perspective. For both ExtractView fuctions, there is a corresponding ExtractCopy function. We strongly encourage users to develop code using ExtractCopy functions first and only use the ExtractView functions in a secondary optimization phase.

There are two Extract functions:

• ExtractCopy - Copy values into a user-provided array.
• ExtractView - Set user-provided array to point to Epetra_IntVector data.

Warning:

A Epetra_Map, Epetra_LocalMap or Epetra_BlockMap object is required for all Epetra_IntVector constructors.

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Constructor & Destructor Documentation

Epetra_IntVector::Epetra_IntVector (  const Epetra_BlockMap &  Map, bool  zeroOut = true )

Basic Epetra_IntVector constuctor. Creates a Epetra_IntVector object and, by default, fills with zero values. Parameters: In  Map - A Epetra_LocalMap, Epetra_Map or Epetra_BlockMap. Warning: Note that, because Epetra_LocalMap derives from Epetra_Map and Epetra_Map derives from Epetra_BlockMap, this constructor works for all three types of Epetra map classes. Parameters: In  zeroOut - If true then the allocated memory will be zeroed out initialy. If false then this memory will not be touched which can be significantly faster. Returns: Pointer to a Epetra_IntVector.

Epetra_IntVector::Epetra_IntVector (  Epetra_DataAccess  CV, const Epetra_BlockMap &  Map, int *  V )

Set vector values from user array. Parameters: In  Epetra_DataAccess - Enumerated type set to Copy or View. In  Map - A Epetra_LocalMap, Epetra_Map or Epetra_BlockMap. In  V - Pointer to an array of integer numbers.. Returns: Integer error code, set to 0 if successful. See Detailed Description section for further discussion.

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Member Function Documentation

int Epetra_IntVector::ExtractCopy (  int *  V  )  const

Put vector values into user-provided array. Parameters: Out  V - Pointer to memory space that will contain the vector values. Returns: Integer error code, set to 0 if successful.

int Epetra_IntVector::ExtractView (  int **  V  )  const

Set user-provided address of V. Parameters: Out  V - Address of a pointer to that will be set to point to the values of the vector. Returns: Integer error code, set to 0 if successful.

int Epetra_IntVector::MaxValue (   )

Find maximum value. Returns: Maximum value across all processors.

int Epetra_IntVector::MinValue (   )

Find minimum value. Returns: Minimum value across all processors.

Epetra_IntVector& Epetra_IntVector::operator= (  const Epetra_IntVector &  Source  )

= Operator. Parameters: In  A - Epetra_IntVector to copy. Returns: Epetra_IntVector.

const int& Epetra_IntVector::operator[] (  int  index  )  const [inline]

Element access function. Returns: V[Index].

int& Epetra_IntVector::operator[] (  int  index  )  [inline]

Element access function. Returns: V[Index].

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

• Epetra_IntVector.h

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