[SYSTEMDS-1853] StepLinreg is failing w/ recompilation issue

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: SystemML 0.15
• Assignee: Matthias Boehm
• Reporter: Matthias Boehm
• Created: 18/Aug/17 06:13
• Updated: 09/Sep/17 03:56
• Resolved: 02/Sep/17 23:37

Description

Our step-wise LinregDS is currently failing with the following NPE on dynamic recompilation

Caused by: java.lang.NullPointerException
        at org.apache.sysml.lops.BinaryScalar.getOpcode(BinaryScalar.java:111)
        at org.apache.sysml.lops.BinaryScalar.getInstructions(BinaryScalar.java:87)
        at org.apache.sysml.lops.compile.Dag.generateControlProgramJobs(Dag.java:1406)
        at org.apache.sysml.lops.compile.Dag.doGreedyGrouping(Dag.java:1176)
        at org.apache.sysml.lops.compile.Dag.getJobs(Dag.java:270)
        at org.apache.sysml.hops.recompile.Recompiler.recompileHopsDag(Recompiler.java:239)
        at org.apache.sysml.runtime.controlprogram.ProgramBlock.execute(ProgramBlock.java:147)

The root cause is that some rewrite modified the input solve to a scalar, which causes the instruction generation of solve to fail because it is not defined over scalars.