[jira] [Created] (SYSTEMML-1655) Wrong cost-based decisions of selecting fusion plans

["Matthias Boehm (JIRA)" <ji...@apache.org>]

Matthias Boehm created SYSTEMML-1655:
----------------------------------------

             Summary: Wrong cost-based decisions of selecting fusion plans
                 Key: SYSTEMML-1655
                 URL: https://issues.apache.org/jira/browse/SYSTEMML-1655
             Project: SystemML
          Issue Type: Bug
    Affects Versions: SystemML 0.14
            Reporter: Matthias Boehm
            Assignee: Matthias Boehm
             Fix For: SystemML 1.0


There are a number of patterns, where the codegen, default cost-based plan selector chooses suboptimal plans. This includes:

1) Overlapping row aggregates
{code}
R1 = t(X) %*% (X %*% v);
R2 = t(X) %*% (w * (X %*% v));
{code}

2) Outer product plans
{code}
R1 = X * (7 + (U %*% t(V) + 3));
R2 = (X * (7 + (U %*% t(V) + 3))) %*% V;
R3 = t(U) %*% (X * (7 + (U %*% t(V) + 3)));
R = as.matrix(sum(R1 * (7 + (R2 %*% R3 + 3))/1e6));
{code}



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