10.7 Overlapped_Vector Class

The Overlapped_Vector Class is used to describe an overlapped vector (existing across all the processors) in the CÆSAR Code Package. An Overlapped_Vector is part of the overall data structure strategy in CÆSAR, which is made up of the following classes: Base_Structure, Data_Index, Assembled_Vector, Distributed_Vector, Overlapped_Vector, and Collected_Array. A description of the overall data structure strategy can be found in the Data_Structures Module.

The form of a collected Overlapped_Vector object is given by:

  Array ( [dim1, [dim2, [dim3,]]] One_Axis [, Many_Axis] )

or

  Array ( dim_ragged_right, One_Axis [, Many_Axis] )
  --> not implemented

where One_Axis refers to the axis which is spread across the processors.

Overlapped_Vector public procedures:

	Fundamental procedures
	Initialize		Initializes an Overlapped_Vector object.
	Finalize		Finalizes an Overlapped_Vector object.
	Valid_State		Returns false iff an Overlapped_Vector object is in an invalid state.
	Initialized		Returns true iff an Overlapped_Vector object has been initialized.
	Operations
	Collect_and_Access		Another name for Get_Values.
	Collect_and_Combine		Collects the values from an Overlapped Vector, and then combines them to form a Distributed Vector, according to the internal Many_of_One_Index object. The resultant Distributed Vector is distributed according to the One Structure of the Overlapped Vector. A combination operator, to be put in the place of ``Combine'', must be specified. Allowed values for ``Combine'' are: Average, MAX, MIN, or SUM. Collect_and_SUM also has an assignment interface.
	Gather		Does the communication necessary to set an Overlapped Vector from a Distributed Vector (also has an assignment interface).
	Get_Values		Collects and accesses the values from an Overlapped_Vector object and returns them in a bare naked array (also has an assignment interface).
	Many_Locus		Returns the Many Structure locus of the Overlapped_Vector object.
	Name		Returns the name of the Overlapped_Vector object.
	One_Locus		Returns the One Structure locus of the Overlapped_Vector object.
	Output		Writes out the Overlapped_Vector object.
	Set_Version		Sets the version number of the Overlapped_Vector object (also has an assignment interface).
	Version		Returns the version number of the Overlapped_Vector object.

Overlapped_Vector public defined type:

	Overlapped_Vector type
	Dimensionality		The number of dimensions that the ``vector'' has, including the dimension that is spread over the processors. ``Ragged_Right'' indices are signified by a Dimensionality of -1. (Ragged_Right is not yet implemented.)
	Dimensions		The extents of the dimensions that the ``vector'' has, including the dimension that is spread over the processors, which is last.
	DV		A pointer to the Distributed Vector that this Overlapped Vector is based on.
	DV_Internal		An internal Distributed Vector that is constructed if the Overlapped Vector is not based on an external Distributed Vector.
	Initialized		Initialization status.
	Many_of_One_Index		The Index that is used to modify the Distributed Vector.
	Many_Structure		Basic data structure which corresponds to the structure of the Distributed Vector that this Overlapped Vector is based on.
	Name		The name for this variable (especially useful in a vector of Overlapped Vectors).
	One_Structure		Basic data structure which corresponds to the way that this Overlapped Vector has been formed. If this Overlapped Vector were to be combined, it would result in a Distributed Vector with a One_Structure basis.
	Overlap_Index		The index for the distributed axis of the off-PE values.
	Overlap_Trace		The trace for the distributed axis of the off-PE values.
	Overlap_Values{n}		Off-PE values in the vector, that are stored locally, with a different length on each PE. Values may have either 1, 2, 3, or 4 dimensions (n = 1, 2, 3, or 4), or be a ragged right array (n = RR). The last dimension is always the dimension to be spread across the processors. Only one of the variables will be allocated for a given object. Ragged right arrays have not been implemented yet.
	Version		Version number which is incremented every time the vector is modified, or is synced with the version number of a data structure that it depends on when it is updated.

The Overlapped_Vector Class code listing contains additional documentation. The Overlapped_Vector Class also contains a Unit Test Program.