icetStrategy(3) 						  IceT Reference						   icetStrategy(3)

NAME

       icetStrategy -- set the strategy used to composite images.

Synopsis
       #include <IceT.h>

       void icetStrategy(   IceTEnum   strategy  );

Description
       The  IceT  API  comes  packaged with several algorithms for compositing images. The algorithm to use is determined by selecting a strategy.
       The strategy is selected with icetStrategy.  A strategy must be selected before icetDrawFrame is called.

       A strategy is chosen from one of the following provided enumerated values:

       ICET_STRATEGY_SEQUENTIAL
	       Basically applies a ``traditional'' single tile composition (such as binary swap) to each tile in  the  order  they  were  defined.
	      Because  each  process must take part in the composition of each tile regardless of whether they draw into it, this strategy is usu-
	      ally inefficient when compositing for more than one tile, but is recommended for the single tile case because it	bypasses  some	of
	      the communication necessary for the other multi-tile strategies.

       ICET_STRATEGY_DIRECT
	       As  each  process renders an image for a tile, that image is sent directly to the process that will display that tile. This usually
	      results in a few processes receiving and processing the majority of the data, and is therefore usually an inefficient strategy.

       ICET_STRATEGY_SPLIT
	       Like ICET_STRATEGY_DIRECT, except that the tiles are split up, and each process is assigned a piece of a tile in such  a  way  that
	      each  process receives and handles about the same amount of data. This strategy is often very efficient, but due to the large amount
	      of messages passed, it has not proven to be very scalable or robust.

       ICET_STRATEGY_REDUCE
	       A two phase algorithm. In the first phase, tile images are redistributed such that each process has one image for one tile. In  the
	      second  phase,  a  ``traditional'' single tile composition is performed for each tile. Since each process contains an image for only
	      one tile, all these compositions may happen simultaneously. This is a well rounded strategy that seems to perform  well  in  a  wide
	      variety  of multi-tile applications. (However, in the special case where only one tile is defined, the sequential strategy is proba-
	      bly better.)

       ICET_STRATEGY_VTREE
	       An extension to the binary tree algorithm for image composition. Sets up a ``virtual'' composition tree for each tile  image.  Pro-
	      cesses  that  belong to multiple trees (because they render to more than one tile) are allowed to float between trees. This strategy
	      is not quite as well load balanced as ICET_STRATEGY_REDUCE or ICET_STRATEGY_SPLIT, but has very well behaved network communication.

       Not all of the strategies support ordered image composition.  ICET_STRATEGY_SEQUENTIAL, ICET_STRATEGY_DIRECT, and  ICET_STRATEGY_REDUCE	do
       support	ordered  image	composition.  ICET_STRATEGY_SPLIT and ICET_STRATEGY_VTREE do not support ordered image composition and will ignore
       ICET_ORDERED_COMPOSITE if it is enabled.

       Some of the strategies, namely ICET_STRATEGY_SEQUENTIAL and ICET_STRATEGY_REDUCE, use a sub-strategy that composites the image for a single
       tile. This single image strategy can also be specified with icetSingleImageStrategy.

Errors
       ICET_INVALID_ENUM
	       The strategy argument does not represent a valid strategy.

Warnings
       None.

Bugs
       None known.

Copyright
       Copyright (C)2003 Sandia Corporation

       Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains certain rights in this software.

       This source code is released under the New BSD License.

See Also
       icetDrawFrame(3), icetGetStrategyName(3) icetSingleImageStrategy(3)

IceT Reference							  August  9, 2010						   icetStrategy(3)