From 5471a777221d44cda2d51d88ca0fa94900efbe31 Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Tue, 25 Feb 2025 12:44:55 +0100
Subject: [PATCH 01/10] create simple Tests

---
 .../functions/codegen/rowAggPattern47.R       | 35 +++++++++++++++++++
 .../functions/codegen/rowAggPattern47.dml     | 28 +++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 src/test/scripts/functions/codegen/rowAggPattern47.R
 create mode 100644 src/test/scripts/functions/codegen/rowAggPattern47.dml

diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.R b/src/test/scripts/functions/codegen/rowAggPattern47.R
new file mode 100644
index 00000000000..329d6778ba4
--- /dev/null
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.R
@@ -0,0 +1,35 @@
+#-------------------------------------------------------------
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+#-------------------------------------------------------------
+
+args<-commandArgs(TRUE)
+options(digits=22)
+library("Matrix")
+library("matrixStats")
+
+rowVars <- function(X) {
+    apply(X, 1, var)
+}
+
+X = matrix(seq(1,6000)/6000, 600, 10, byrow=TRUE);
+
+R = as.matrix(sum(rowVars(X)));
+
+writeMM(as(R, "CsparseMatrix"), paste(args[2], "S", sep=""));
diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.dml b/src/test/scripts/functions/codegen/rowAggPattern47.dml
new file mode 100644
index 00000000000..b0c4bea9ce8
--- /dev/null
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.dml
@@ -0,0 +1,28 @@
+#-------------------------------------------------------------
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+#-------------------------------------------------------------
+
+
+X = matrix(seq(1,6000)/6000, 600, 10);
+while(FALSE){}
+
+R = as.matrix(sum(rowVars(X)));
+
+write(R, $1)

From 382565cdd34b44e79de1cd25fe588671a406d6ac Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Tue, 25 Feb 2025 12:45:55 +0100
Subject: [PATCH 02/10] add Tests to config files

---
 .../sysds/test/functions/codegen/RowAggTmplTest.java   | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java b/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
index d3c9edf8e8c..cf695961805 100644
--- a/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
+++ b/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
@@ -87,6 +87,7 @@ public class RowAggTmplTest extends AutomatedTestBase
 	private static final String TEST_NAME44 = TEST_NAME+"44"; //maxpool(X - mean(X)) + 7;
 	private static final String TEST_NAME45 = TEST_NAME+"45"; //vector allocation;
 	private static final String TEST_NAME46 = TEST_NAME+"46"; //conv2d(X - mean(X), F1) + conv2d(X - mean(X), F2);
+	private static final String TEST_NAME47 = TEST_NAME+"47"; //sum(rowVar(X))
 	
 	private static final String TEST_DIR = "functions/codegen/";
 	private static final String TEST_CLASS_DIR = TEST_DIR + RowAggTmplTest.class.getSimpleName() + "/";
@@ -98,7 +99,7 @@ public class RowAggTmplTest extends AutomatedTestBase
 	@Override
 	public void setUp() {
 		TestUtils.clearAssertionInformation();
-		for(int i=1; i<=46; i++)
+		for(int i=1; i<=47; i++)
 			addTestConfiguration( TEST_NAME+i, new TestConfiguration(TEST_CLASS_DIR, TEST_NAME+i, new String[] { String.valueOf(i) }) );
 	}
 	
@@ -795,6 +796,11 @@ public void testCodegenRowAgg46SP() {
 		testCodegenIntegration( TEST_NAME46, false, ExecType.SPARK );
 	}
 
+	@Test
+	public void testCodegenRowAgg47() {
+		testCodegenIntegration(TEST_NAME47, false, ExecType.CP);
+	}
+
 	private void testCodegenIntegration( String testname, boolean rewrites, ExecType instType )
 	{
 		boolean oldFlag = OptimizerUtils.ALLOW_ALGEBRAIC_SIMPLIFICATION;
@@ -807,7 +813,7 @@ private void testCodegenIntegration( String testname, boolean rewrites, ExecType
 			
 			String HOME = SCRIPT_DIR + TEST_DIR;
 			fullDMLScriptName = HOME + testname + ".dml";
-			programArgs = new String[]{"-stats", "-args", output("S") };
+			programArgs = new String[]{"-explain", "codegen", "-stats", "-args", output("S") };
 			
 			fullRScriptName = HOME + testname + ".R";
 			rCmd = getRCmd(inputDir(), expectedDir());

From 53484be93246105044d1130e253b13b3ec330b69 Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Tue, 25 Feb 2025 17:09:04 +0100
Subject: [PATCH 03/10] implement rowVar into the compiler

---
 .../sysds/hops/codegen/cplan/CNodeUnary.java       |  4 +++-
 .../sysds/hops/codegen/cplan/java/Unary.java       |  2 +-
 .../sysds/hops/codegen/template/TemplateRow.java   |  2 +-
 .../sysds/runtime/codegen/LibSpoofPrimitives.java  | 14 +++++++++++++-
 4 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/main/java/org/apache/sysds/hops/codegen/cplan/CNodeUnary.java b/src/main/java/org/apache/sysds/hops/codegen/cplan/CNodeUnary.java
index 93cdb2f6612..fe67995b6b5 100644
--- a/src/main/java/org/apache/sysds/hops/codegen/cplan/CNodeUnary.java
+++ b/src/main/java/org/apache/sysds/hops/codegen/cplan/CNodeUnary.java
@@ -33,7 +33,7 @@ public class CNodeUnary extends CNode
 	public enum UnaryType {
 		LOOKUP_R, LOOKUP_C, LOOKUP_RC, LOOKUP0, //codegen specific
 		ROW_SUMS, ROW_SUMSQS, ROW_COUNTNNZS, //codegen specific
-		ROW_MEANS, ROW_MINS, ROW_MAXS,
+		ROW_MEANS, ROW_MINS, ROW_MAXS, ROW_VARS,
 		VECT_EXP, VECT_POW2, VECT_MULT2, VECT_SQRT, VECT_LOG,
 		VECT_ABS, VECT_ROUND, VECT_CEIL, VECT_FLOOR, VECT_SIGN, 
 		VECT_SIN, VECT_COS, VECT_TAN, VECT_ASIN, VECT_ACOS, VECT_ATAN, 
@@ -139,6 +139,7 @@ public String toString() {
 			case ROW_MINS:   return "u(Rmin)";
 			case ROW_MAXS:   return "u(Rmax)";
 			case ROW_MEANS:  return "u(Rmean)";
+			case ROW_VARS:	 return "u(Rvar)";
 			case ROW_COUNTNNZS: return "u(Rnnz)";
 			case VECT_EXP:
 			case VECT_POW2:
@@ -210,6 +211,7 @@ public void setOutputDims() {
 			case ROW_MINS:
 			case ROW_MAXS:
 			case ROW_MEANS:
+			case ROW_VARS:
 			case ROW_COUNTNNZS:
 			case EXP:
 			case LOOKUP_R:
diff --git a/src/main/java/org/apache/sysds/hops/codegen/cplan/java/Unary.java b/src/main/java/org/apache/sysds/hops/codegen/cplan/java/Unary.java
index 50ea2bace86..d8a1085df58 100644
--- a/src/main/java/org/apache/sysds/hops/codegen/cplan/java/Unary.java
+++ b/src/main/java/org/apache/sysds/hops/codegen/cplan/java/Unary.java
@@ -32,12 +32,12 @@ public String getTemplate(UnaryType type, boolean sparse) {
 			case ROW_MINS:
 			case ROW_MAXS:
 			case ROW_MEANS:
+			case ROW_VARS:
 			case ROW_COUNTNNZS: {
 				String vectName = StringUtils.capitalize(type.name().substring(4, type.name().length()-1).toLowerCase());
 				return sparse ? "    double %TMP% = LibSpoofPrimitives.vect"+vectName+"(%IN1v%, %IN1i%, %POS1%, alen, len);\n":
 						"    double %TMP% = LibSpoofPrimitives.vect"+vectName+"(%IN1%, %POS1%, %LEN%);\n";
 			}
-
 			case VECT_EXP:
 			case VECT_POW2:
 			case VECT_MULT2:
diff --git a/src/main/java/org/apache/sysds/hops/codegen/template/TemplateRow.java b/src/main/java/org/apache/sysds/hops/codegen/template/TemplateRow.java
index 4ac38b1487c..82faf9b12ec 100644
--- a/src/main/java/org/apache/sysds/hops/codegen/template/TemplateRow.java
+++ b/src/main/java/org/apache/sysds/hops/codegen/template/TemplateRow.java
@@ -67,7 +67,7 @@
 
 public class TemplateRow extends TemplateBase 
 {
-	private static final AggOp[] SUPPORTED_ROW_AGG = new AggOp[]{AggOp.SUM, AggOp.MIN, AggOp.MAX, AggOp.MEAN};
+	private static final AggOp[] SUPPORTED_ROW_AGG = new AggOp[]{AggOp.SUM, AggOp.MIN, AggOp.MAX, AggOp.MEAN, AggOp.VAR};
 	private static final OpOp1[] SUPPORTED_VECT_UNARY = new OpOp1[]{
 		OpOp1.EXP, OpOp1.SQRT, OpOp1.LOG, OpOp1.ABS, OpOp1.ROUND, OpOp1.CEIL, OpOp1.FLOOR, OpOp1.SIGN,
 		OpOp1.SIN, OpOp1.COS, OpOp1.TAN, OpOp1.ASIN, OpOp1.ACOS, OpOp1.ATAN, OpOp1.SINH, OpOp1.COSH, OpOp1.TANH,
diff --git a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
index 6497b6f321f..4672e99c224 100644
--- a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
+++ b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
@@ -2151,7 +2151,19 @@ public static double[] vectConv2dmmWrite(double[] a, double[] b, int ai, int bi,
 			new DenseBlockFP64(new int[]{K, PQ}, c), PQ, CRS, 0, K, 0, PQ);
 		return c;
 	} 
-	
+
+	public static double vectVar(double[] a, int ai, int len) {
+		double meanVal = vectMean(a, ai, len);
+		double[] aSqr = vectPow2Write(a, ai, len);
+		return ((double) 1 /len)*(vectSum(aSqr, ai, len)-meanVal);
+	}
+
+	public static double vectVar(double[] avals, int[] aix, int ai, int alen, int len) {
+		double meanVal = vectMean(avals, aix, ai, alen, len);
+		double[] avalsSqr = vectPow2Write(avals, aix, ai, alen, len);
+		return ((double) 1 /len)*(vectSum(avalsSqr, ai, len)-meanVal);
+	}
+
 	//complex builtin functions that are not directly generated
 	//(included here in order to reduce the number of imports)
 	

From 38735536febf380a051091f43dd331be1355e973 Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Wed, 26 Feb 2025 23:30:44 +0100
Subject: [PATCH 04/10] fix out of bounds exception

---
 .../apache/sysds/runtime/codegen/LibSpoofPrimitives.java  | 8 ++++----
 src/test/scripts/functions/codegen/rowAggPattern47.R      | 3 ++-
 src/test/scripts/functions/codegen/rowAggPattern47.dml    | 3 ++-
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
index 4672e99c224..baf1f844d0a 100644
--- a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
+++ b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
@@ -2153,15 +2153,15 @@ public static double[] vectConv2dmmWrite(double[] a, double[] b, int ai, int bi,
 	} 
 
 	public static double vectVar(double[] a, int ai, int len) {
-		double meanVal = vectMean(a, ai, len);
+		double meanVal = Math.pow(vectMean(a, ai, len), 2);
 		double[] aSqr = vectPow2Write(a, ai, len);
-		return ((double) 1 /len)*(vectSum(aSqr, ai, len)-meanVal);
+		return ((double) 1 /len)*(vectSum(aSqr, 0, len)-meanVal);
 	}
 
 	public static double vectVar(double[] avals, int[] aix, int ai, int alen, int len) {
-		double meanVal = vectMean(avals, aix, ai, alen, len);
+		double meanVal = Math.pow(vectMean(avals, aix, ai, alen, len), 2);
 		double[] avalsSqr = vectPow2Write(avals, aix, ai, alen, len);
-		return ((double) 1 /len)*(vectSum(avalsSqr, ai, len)-meanVal);
+		return ((double) 1 /len)*(vectSum(avalsSqr, 0, alen)-meanVal);
 	}
 
 	//complex builtin functions that are not directly generated
diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.R b/src/test/scripts/functions/codegen/rowAggPattern47.R
index 329d6778ba4..073fe7707a0 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern47.R
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.R
@@ -28,7 +28,8 @@ rowVars <- function(X) {
     apply(X, 1, var)
 }
 
-X = matrix(seq(1,6000)/6000, 600, 10, byrow=TRUE);
+# X = matrix(seq(1,6000)/6000, 600, 10, byrow=TRUE);
+X = matrix(2, 10, 10);
 
 R = as.matrix(sum(rowVars(X)));
 
diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.dml b/src/test/scripts/functions/codegen/rowAggPattern47.dml
index b0c4bea9ce8..e33de1a57d8 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern47.dml
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.dml
@@ -19,8 +19,9 @@
 #
 #-------------------------------------------------------------
 
+#X = matrix(seq(1,6000)/6000, 600, 10);
+X = matrix(2, 10, 10)
 
-X = matrix(seq(1,6000)/6000, 600, 10);
 while(FALSE){}
 
 R = as.matrix(sum(rowVars(X)));

From 19b12eb21b214ffa1b8a5ea5bc56718c488a8064 Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Thu, 27 Feb 2025 14:51:44 +0100
Subject: [PATCH 05/10] debug vectVar

---
 .../org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java  | 4 ++--
 src/test/scripts/functions/codegen/rowAggPattern47.R          | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
index baf1f844d0a..8b6dd834a81 100644
--- a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
+++ b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
@@ -2155,13 +2155,13 @@ public static double[] vectConv2dmmWrite(double[] a, double[] b, int ai, int bi,
 	public static double vectVar(double[] a, int ai, int len) {
 		double meanVal = Math.pow(vectMean(a, ai, len), 2);
 		double[] aSqr = vectPow2Write(a, ai, len);
-		return ((double) 1 /len)*(vectSum(aSqr, 0, len)-meanVal);
+		return ((double) 1 /len)*vectSum(aSqr, 0, len)-meanVal;
 	}
 
 	public static double vectVar(double[] avals, int[] aix, int ai, int alen, int len) {
 		double meanVal = Math.pow(vectMean(avals, aix, ai, alen, len), 2);
 		double[] avalsSqr = vectPow2Write(avals, aix, ai, alen, len);
-		return ((double) 1 /len)*(vectSum(avalsSqr, 0, alen)-meanVal);
+		return ((double) 1 /len)*vectSum(avalsSqr, 0, alen)-meanVal;
 	}
 
 	//complex builtin functions that are not directly generated
diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.R b/src/test/scripts/functions/codegen/rowAggPattern47.R
index 073fe7707a0..0efa05ad96f 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern47.R
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.R
@@ -25,7 +25,7 @@ library("Matrix")
 library("matrixStats")
 
 rowVars <- function(X) {
-    apply(X, 1, var)
+  apply(X, 1, function(x) sum((x - mean(x))^2) / length(x))
 }
 
 # X = matrix(seq(1,6000)/6000, 600, 10, byrow=TRUE);

From af60070c10215ec68ece9466c7a3ce7bf79f9b53 Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Mon, 3 Mar 2025 09:39:30 +0100
Subject: [PATCH 06/10] sparse vectVar fix

---
 .../org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
index 8b6dd834a81..28db83a8634 100644
--- a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
+++ b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
@@ -2161,7 +2161,7 @@ public static double vectVar(double[] a, int ai, int len) {
 	public static double vectVar(double[] avals, int[] aix, int ai, int alen, int len) {
 		double meanVal = Math.pow(vectMean(avals, aix, ai, alen, len), 2);
 		double[] avalsSqr = vectPow2Write(avals, aix, ai, alen, len);
-		return ((double) 1 /len)*vectSum(avalsSqr, 0, alen)-meanVal;
+		return ((double) 1 /len)*vectSum(avalsSqr, 0, len)-meanVal;
 	}
 
 	//complex builtin functions that are not directly generated

From 85d20c2eb0c50487654903bcfd1f06ecf702c01d Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Fri, 7 Mar 2025 06:59:30 +0100
Subject: [PATCH 07/10] test files

---
 .../functions/codegen/rowAggPattern47.R       |  4 +--
 .../functions/codegen/rowAggPattern47.dml     |  4 +--
 .../functions/codegen/rowAggPattern48.R       | 27 +++++++++++++++++++
 .../functions/codegen/rowAggPattern48.dml     | 26 ++++++++++++++++++
 4 files changed, 57 insertions(+), 4 deletions(-)
 create mode 100644 src/test/scripts/functions/codegen/rowAggPattern48.R
 create mode 100644 src/test/scripts/functions/codegen/rowAggPattern48.dml

diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.R b/src/test/scripts/functions/codegen/rowAggPattern47.R
index 0efa05ad96f..998b8ed96fb 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern47.R
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.R
@@ -28,8 +28,8 @@ rowVars <- function(X) {
   apply(X, 1, function(x) sum((x - mean(x))^2) / length(x))
 }
 
-# X = matrix(seq(1,6000)/6000, 600, 10, byrow=TRUE);
-X = matrix(2, 10, 10);
+X = matrix(seq(7, 100*100+6), 100, 100, byrow=TRUE);
+# X = matrix(2, 10, 10);
 
 R = as.matrix(sum(rowVars(X)));
 
diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.dml b/src/test/scripts/functions/codegen/rowAggPattern47.dml
index e33de1a57d8..d2f7aa4f9b7 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern47.dml
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.dml
@@ -19,8 +19,8 @@
 #
 #-------------------------------------------------------------
 
-#X = matrix(seq(1,6000)/6000, 600, 10);
-X = matrix(2, 10, 10)
+X = matrix(seq(7, 100*100+6), 100, 100);
+#X = matrix(2, 10, 10)
 
 while(FALSE){}
 
diff --git a/src/test/scripts/functions/codegen/rowAggPattern48.R b/src/test/scripts/functions/codegen/rowAggPattern48.R
new file mode 100644
index 00000000000..ca812a0fa61
--- /dev/null
+++ b/src/test/scripts/functions/codegen/rowAggPattern48.R
@@ -0,0 +1,27 @@
+#-------------------------------------------------------------
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+#-------------------------------------------------------------
+
+
+while(FALSE){}
+
+R = as.matrix(sum(rowVars(X)));
+
+write(R, $1)
diff --git a/src/test/scripts/functions/codegen/rowAggPattern48.dml b/src/test/scripts/functions/codegen/rowAggPattern48.dml
new file mode 100644
index 00000000000..2ff5003838b
--- /dev/null
+++ b/src/test/scripts/functions/codegen/rowAggPattern48.dml
@@ -0,0 +1,26 @@
+#-------------------------------------------------------------
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+#-------------------------------------------------------------
+
+while(FALSE){}
+
+R = as.matrix(sum(rowVars(X)));
+
+write(R, $1)
\ No newline at end of file

From e14c35b0993bf935b3a85d72ea6f99792ac4d4dc Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Tue, 18 Mar 2025 16:23:32 +0100
Subject: [PATCH 08/10] write tests

---
 .../scripts/functions/codegen/rowAggPattern47.R     | 12 ++++++------
 .../scripts/functions/codegen/rowAggPattern47.dml   |  6 +++---
 .../scripts/functions/codegen/rowAggPattern48.R     | 13 +++++++++++--
 .../scripts/functions/codegen/rowAggPattern48.dml   |  4 ++++
 4 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.R b/src/test/scripts/functions/codegen/rowAggPattern47.R
index 998b8ed96fb..9d6d4bc9f65 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern47.R
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.R
@@ -24,13 +24,13 @@ options(digits=22)
 library("Matrix")
 library("matrixStats")
 
-rowVars <- function(X) {
-  apply(X, 1, function(x) sum((x - mean(x))^2) / length(x))
-}
+# rowVars <- function(X) {
+#   apply(X, 1, function(x) sum((x - mean(x))^2) / length(x))
+# }
 
-X = matrix(seq(7, 100*100+6), 100, 100, byrow=TRUE);
-# X = matrix(2, 10, 10);
+X = matrix(seq(7, 50*10+6), 50, 10, byrow=TRUE);
+z = seq(1,50)
 
-R = as.matrix(sum(rowVars(X)));
+R = as.matrix(sum(X + rowVars(X)));
 
 writeMM(as(R, "CsparseMatrix"), paste(args[2], "S", sep=""));
diff --git a/src/test/scripts/functions/codegen/rowAggPattern47.dml b/src/test/scripts/functions/codegen/rowAggPattern47.dml
index d2f7aa4f9b7..e3ee077fc14 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern47.dml
+++ b/src/test/scripts/functions/codegen/rowAggPattern47.dml
@@ -19,11 +19,11 @@
 #
 #-------------------------------------------------------------
 
-X = matrix(seq(7, 100*100+6), 100, 100);
-#X = matrix(2, 10, 10)
+X = matrix(seq(7, 50*10+6), 50, 10);
+z = seq(1,50)
 
 while(FALSE){}
 
-R = as.matrix(sum(rowVars(X)));
+R = as.matrix(sum(X + rowVars(X)));
 
 write(R, $1)
diff --git a/src/test/scripts/functions/codegen/rowAggPattern48.R b/src/test/scripts/functions/codegen/rowAggPattern48.R
index ca812a0fa61..bec1427d619 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern48.R
+++ b/src/test/scripts/functions/codegen/rowAggPattern48.R
@@ -18,10 +18,19 @@
 # under the License.
 #
 #-------------------------------------------------------------
+args<-commandArgs(TRUE)
+options(digits=22)
+library("Matrix")
+library("matrixStats")
 
+# rowVars <- function(X) {
+#   apply(X, 1, function(x) sum((x - mean(x))^2) / length(x))
+# }
 
-while(FALSE){}
+Z = matrix(seq(1,10), 1, 10)
+Y = matrix(0, 10, 10)
+X = rbind(Y, Z, Y)
 
 R = as.matrix(sum(rowVars(X)));
 
-write(R, $1)
+writeMM(as(R, "CsparseMatrix"), paste(args[2], "S", sep=""));
diff --git a/src/test/scripts/functions/codegen/rowAggPattern48.dml b/src/test/scripts/functions/codegen/rowAggPattern48.dml
index 2ff5003838b..c367a359cdf 100644
--- a/src/test/scripts/functions/codegen/rowAggPattern48.dml
+++ b/src/test/scripts/functions/codegen/rowAggPattern48.dml
@@ -19,6 +19,10 @@
 #
 #-------------------------------------------------------------
 
+Z = matrix(seq(1,10), 1, 10)
+Y = matrix(0, 10, 10)
+X = rbind(Y, Z, Y)
+
 while(FALSE){}
 
 R = as.matrix(sum(rowVars(X)));

From 341cb80cadbf38510d2588a86f8760d1823f5528 Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Tue, 18 Mar 2025 16:23:51 +0100
Subject: [PATCH 09/10] adjust var function

---
 .../org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java  | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
index 28db83a8634..6c0dc395c3f 100644
--- a/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
+++ b/src/main/java/org/apache/sysds/runtime/codegen/LibSpoofPrimitives.java
@@ -2155,13 +2155,13 @@ public static double[] vectConv2dmmWrite(double[] a, double[] b, int ai, int bi,
 	public static double vectVar(double[] a, int ai, int len) {
 		double meanVal = Math.pow(vectMean(a, ai, len), 2);
 		double[] aSqr = vectPow2Write(a, ai, len);
-		return ((double) 1 /len)*vectSum(aSqr, 0, len)-meanVal;
+		return (vectSum(aSqr, 0, len)-len*meanVal)/(len-1);
 	}
 
 	public static double vectVar(double[] avals, int[] aix, int ai, int alen, int len) {
 		double meanVal = Math.pow(vectMean(avals, aix, ai, alen, len), 2);
 		double[] avalsSqr = vectPow2Write(avals, aix, ai, alen, len);
-		return ((double) 1 /len)*vectSum(avalsSqr, 0, len)-meanVal;
+		return (vectSum(avalsSqr, 0, len)-len*meanVal)/(len-1);
 	}
 
 	//complex builtin functions that are not directly generated

From c925ed9020ad81c870bd04e7796c09574b4eb60d Mon Sep 17 00:00:00 2001
From: Frxms <tomoki.mengel@gmail.com>
Date: Tue, 18 Mar 2025 16:30:23 +0100
Subject: [PATCH 10/10] create and run test configs

---
 .../functions/codegen/RowAggTmplTest.java     | 36 ++++++++++++++++---
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java b/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
index cf695961805..b89f3007b4a 100644
--- a/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
+++ b/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
@@ -87,8 +87,9 @@ public class RowAggTmplTest extends AutomatedTestBase
 	private static final String TEST_NAME44 = TEST_NAME+"44"; //maxpool(X - mean(X)) + 7;
 	private static final String TEST_NAME45 = TEST_NAME+"45"; //vector allocation;
 	private static final String TEST_NAME46 = TEST_NAME+"46"; //conv2d(X - mean(X), F1) + conv2d(X - mean(X), F2);
-	private static final String TEST_NAME47 = TEST_NAME+"47"; //sum(rowVar(X))
-	
+	private static final String TEST_NAME47 = TEST_NAME+"47"; //sum(X + rowVars(X))
+	private static final String TEST_NAME48 = TEST_NAME+"48"; //sum(rowVars(X))
+
 	private static final String TEST_DIR = "functions/codegen/";
 	private static final String TEST_CLASS_DIR = TEST_DIR + RowAggTmplTest.class.getSimpleName() + "/";
 	private final static String TEST_CONF = "SystemDS-config-codegen.xml";
@@ -99,7 +100,7 @@ public class RowAggTmplTest extends AutomatedTestBase
 	@Override
 	public void setUp() {
 		TestUtils.clearAssertionInformation();
-		for(int i=1; i<=47; i++)
+		for(int i=1; i<=48; i++)
 			addTestConfiguration( TEST_NAME+i, new TestConfiguration(TEST_CLASS_DIR, TEST_NAME+i, new String[] { String.valueOf(i) }) );
 	}
 	
@@ -797,8 +798,33 @@ public void testCodegenRowAgg46SP() {
 	}
 
 	@Test
-	public void testCodegenRowAgg47() {
-		testCodegenIntegration(TEST_NAME47, false, ExecType.CP);
+	public void testCodegenRowAggRewrite47CP() {
+		testCodegenIntegration( TEST_NAME47, true, ExecType.CP );
+	}
+
+	@Test
+	public void testCodegenRowAgg47CP() {
+		testCodegenIntegration( TEST_NAME47, false, ExecType.CP );
+	}
+
+	@Test
+	public void testCodegenRowAgg47SP() {
+		testCodegenIntegration( TEST_NAME47, false, ExecType.SPARK );
+	}
+
+	@Test
+	public void testCodegenRowAggRewrite48CP() {
+		testCodegenIntegration( TEST_NAME48, true, ExecType.CP );
+	}
+
+	@Test
+	public void testCodegenRowAgg48CP() {
+		testCodegenIntegration( TEST_NAME48, false, ExecType.CP );
+	}
+
+	@Test
+	public void testCodegenRowAgg48SP() {
+		testCodegenIntegration( TEST_NAME48, false, ExecType.SPARK );
 	}
 
 	private void testCodegenIntegration( String testname, boolean rewrites, ExecType instType )