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new 27caa8ba2c [SYSTEMDS-3149] Improved decisionTree
(robustness/rmEmpty-short-circuit)
27caa8ba2c is described below
commit 27caa8ba2c40111b486d3691bccafb23c1d285bc
Author: Matthias Boehm <[email protected]>
AuthorDate: Fri May 5 20:58:00 2023 +0200
[SYSTEMDS-3149] Improved decisionTree (robustness/rmEmpty-short-circuit)
This patch improves the robustness and performance of the decisionTree /
randomForest builtins when performing value and/or feature sampling.
First, when sampling features (max_features<1.0) one might sample zero
features which led to crashes. The likelihood of this happens directly
depends on the number_of_features^max_features.
Second, value and feature sampling might sample all values/features,
especially when very close to max_features. So far, removeEmpty scanned
despite a form of short-circuiting, the selection vector and created new
output matrix objects which polluted the buffer pool. We now check
upfront the number of non-zeros in given selection vectors, short-
circuit the entire computation, and even return the original input
meta data object, avoiding duplicates in the buffer pool.
On a scenario of running 1000 removeEmpty with full selection vector on
a 10M x 10 matrix, this patch improved the runtime stats as follows:
Cache writes (Li/WB/FS/HDFS): 1/1003/0/0.
Cache times (ACQr/m, RLS, EXP): 0.004/0.012/0.077/0.000 sec.
Heavy hitter instructions:
1 rmempty 105.928 1000
-->
Cache writes (Li/WB/FS/HDFS): 1/3/0/0.
Cache times (ACQr/m, RLS, EXP): 0.004/0.000/0.006/0.000 sec.
Heavy hitter instructions:
5 rmempty 0.026 1000
---
scripts/builtin/decisionTree.dml | 2 ++
.../runtime/instructions/cp/ParameterizedBuiltinCPInstruction.java | 7 +++++--
.../java/org/apache/sysds/runtime/matrix/data/LibMatrixReorg.java | 6 ++++++
3 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/scripts/builtin/decisionTree.dml b/scripts/builtin/decisionTree.dml
index 384f591b73..85e414c61d 100644
--- a/scripts/builtin/decisionTree.dml
+++ b/scripts/builtin/decisionTree.dml
@@ -162,6 +162,8 @@ findBestSplit = function(Matrix[Double] X2, Matrix[Double]
y2, Matrix[Double] fo
if( max_features < 1.0 ) {
rI = rand(rows=n, cols=1, seed=seed) <= (n^max_features/n);
feat = removeEmpty(target=feat, margin="rows", select=rI);
+ if( sum(feat) == 0 ) #sample at least one
+ feat[1,1] = round(rand(rows=1, cols=1, min=1, max=n));
}
# evaluate features and feature splits
diff --git
a/src/main/java/org/apache/sysds/runtime/instructions/cp/ParameterizedBuiltinCPInstruction.java
b/src/main/java/org/apache/sysds/runtime/instructions/cp/ParameterizedBuiltinCPInstruction.java
index a67f8cd20d..9dfbdbec7f 100644
---
a/src/main/java/org/apache/sysds/runtime/instructions/cp/ParameterizedBuiltinCPInstruction.java
+++
b/src/main/java/org/apache/sysds/runtime/instructions/cp/ParameterizedBuiltinCPInstruction.java
@@ -227,10 +227,13 @@ public class ParameterizedBuiltinCPInstruction extends
ComputationCPInstruction
// compute the result
boolean emptyReturn =
Boolean.parseBoolean(params.get("empty.return").toLowerCase());
- MatrixBlock soresBlock =
target.removeEmptyOperations(new MatrixBlock(), margin.equals("rows"),
emptyReturn, select);
+ MatrixBlock ret =
target.removeEmptyOperations(new MatrixBlock(), margin.equals("rows"),
emptyReturn, select);
// release locks
- ec.setMatrixOutput(output.getName(),
soresBlock);
+ if( target == ret ) //short-circuit (avoid
buffer pool pollution)
+ ec.setVariable(output.getName(),
ec.getVariable(params.get("target")));
+ else
+ ec.setMatrixOutput(output.getName(),
ret);
ec.releaseMatrixInput(params.get("target"));
if(params.containsKey("select"))
ec.releaseMatrixInput(params.get("select"));
diff --git
a/src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixReorg.java
b/src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixReorg.java
index 260c8b26a6..587fe74af1 100644
--- a/src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixReorg.java
+++ b/src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixReorg.java
@@ -661,6 +661,12 @@ public class LibMatrixReorg {
return ret;
}
+ // short-circuit for select-all (shallow-copy input)
+ if( select != null && (select.nonZeros ==
(rows?in.rlen:in.clen)) ) {
+ return in;
+ }
+
+ // core removeEmpty
if( rows )
return removeEmptyRows(in, ret, select, emptyReturn);
else //cols
