Package org.apache.sysds.hops.rewrite

Class RewriteSplitDagDataDependentOperators

java.lang.Object

org.apache.sysds.hops.rewrite.StatementBlockRewriteRule

org.apache.sysds.hops.rewrite.RewriteSplitDagDataDependentOperators

public class RewriteSplitDagDataDependentOperators
extends StatementBlockRewriteRule

Rule: Split Hop DAG after specific data-dependent operators. This is important to create recompile hooks if output dimensions are usually significantly overestimated. This is a recursive statementblock rewrite rule. NOTE: Before we used AssignmentStatement.controlStatement() in order to force statementblock cuts. However, this (1) cuts not only after but before-and-after (which prevents certain rewrites because the input operators are unknown), and (2) is statement-centric which potentially prevents the cut right after the problematic operation. TODO: Cleanup runtime to never access individual statements of potentially split statements blocks again (for consistency). However, currently it is only used in places (e.g., parfor optimizer) that are not directly affected.

Constructor Summary

Constructors

Constructor	Description
RewriteSplitDagDataDependentOperators()

Method Summary

Modifier and Type	Method	Description
boolean	createsSplitDag()	Indicates if the rewrite potentially splits dags, which is used for phase ordering of rewrites.
List<StatementBlock>	rewriteStatementBlock(StatementBlock sb, ProgramRewriteStatus state)	Handle an arbitrary statement block.
List<StatementBlock>	rewriteStatementBlocks(List<StatementBlock> sbs, ProgramRewriteStatus sate)	Handle a list of statement blocks.

Methods inherited from class org.apache.sysds.hops.rewrite.StatementBlockRewriteRule

createCutVarName

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RewriteSplitDagDataDependentOperators

public RewriteSplitDagDataDependentOperators()

Method Detail

createsSplitDag

public boolean createsSplitDag()

Description copied from class: StatementBlockRewriteRule

Indicates if the rewrite potentially splits dags, which is used for phase ordering of rewrites.

Specified by:

createsSplitDag in class StatementBlockRewriteRule

Returns:

true if dag splits are possible.

rewriteStatementBlock

public List<StatementBlock> rewriteStatementBlock(StatementBlock sb,
                                                  ProgramRewriteStatus state)

Description copied from class: StatementBlockRewriteRule

Handle an arbitrary statement block. Specific type constraints have to be ensured within the individual rewrites. If a rewrite does not apply to individual blocks, it should simply return the input block.

Specified by:

rewriteStatementBlock in class StatementBlockRewriteRule

Parameters:

sb - statement block

state - program rewrite status

Returns:

list of statement blocks

rewriteStatementBlocks

public List<StatementBlock> rewriteStatementBlocks(List<StatementBlock> sbs,
                                                   ProgramRewriteStatus sate)

Description copied from class: StatementBlockRewriteRule

Handle a list of statement blocks. Specific type constraints have to be ensured within the individual rewrites. If a rewrite does not require sequence access, it should simply return the input list of statement blocks.

Specified by:

rewriteStatementBlocks in class StatementBlockRewriteRule

Parameters:

sbs - list of statement blocks

sate - program rewrite status

Returns:

list of statement blocks