[SYSTEMDS-3837] Fix trace error handling (only squared matrices)

The trace of a matrix is only defined for squared matrices and our
kernels also assume that internally. However, there was on systematic
error handling leading to some invalid invocations failing with
index-out-of-bounds while others succeeded.

Author: mboehm7

src/main/java/org/apache/sysds/parser/BuiltinFunctionExpression.java

@@ -942,9 +942,15 @@ public void validateExpression(HashMap<String, DataIdentifier> ids, HashMap<Stri
 			output.setBlocksize (id.getBlocksize());
 			output.setValueType(id.getValueType());
 			break;
+		case TRACE:
+			if(getFirstExpr().getOutput().dimsKnown() 
+				&& getFirstExpr().getOutput().getDim1() != getFirstExpr().getOutput().getDim2()) 
+			{
+				raiseValidateError("Trace is only defined on squared matrices but found ["
+					+getFirstExpr().getOutput().getDim1()+"x"+getFirstExpr().getOutput().getDim2()+"].", conditional);
+			}
 		case SUM:
 		case PROD:
-		case TRACE:
 		case SD:
 		case VAR:
 			// sum(X);

src/test/java/org/apache/sysds/test/functions/aggregate/TraceTest.java

@@ -44,16 +44,20 @@ public class TraceTest extends AutomatedTestBase {
 
 	private final static String TEST_DIR = "functions/aggregate/";
 	private static final String TEST_CLASS_DIR = TEST_DIR + TraceTest.class.getSimpleName() + "/";
-	private final static String TEST_GENERAL = "General";
-	private final static String TEST_SCALAR = "Scalar";
+	private final static String TEST_GENERAL = "TraceTest";
+	private final static String TEST_SCALAR = "TraceScalarTest";
+	private final static String TEST_INVALID1 = "TraceInvalid1";
+	private final static String TEST_INVALID2 = "TraceInvalid2";
 
 	@Override
 	public void setUp() {
 		// positive tests
-		addTestConfiguration(TEST_GENERAL, new TestConfiguration(TEST_CLASS_DIR, "TraceTest", new String[] {"b"}));
+		addTestConfiguration(TEST_GENERAL, new TestConfiguration(TEST_CLASS_DIR, TEST_GENERAL, new String[] {"b"}));
 
 		// negative tests
-		addTestConfiguration(TEST_SCALAR, new TestConfiguration(TEST_CLASS_DIR, "TraceScalarTest", new String[] {"b"}));
+		addTestConfiguration(TEST_SCALAR, new TestConfiguration(TEST_CLASS_DIR, TEST_SCALAR, new String[] {"b"}));
+		addTestConfiguration(TEST_INVALID1, new TestConfiguration(TEST_CLASS_DIR, TEST_INVALID1, new String[] {"b"}));
+		addTestConfiguration(TEST_INVALID2, new TestConfiguration(TEST_CLASS_DIR, TEST_INVALID2, new String[] {"b"}));
 	}
 
 	@Test
@@ -85,16 +89,25 @@ public void testGeneral() {
 
 	@Test
 	public void testScalar() {
-		int scalar = 12;
-
 		TestConfiguration config = getTestConfiguration(TEST_SCALAR);
-		config.addVariable("scalar", scalar);
+		config.addVariable("scalar", 12);
 
 		createHelperMatrix();
-
 		loadTestConfiguration(config);
-
+		runTest(true, LanguageException.class);
+	}
+	
+	@Test
+	public void testInvalid1() {
+		TestConfiguration config = getTestConfiguration(TEST_INVALID1);
+		loadTestConfiguration(config);
 		runTest(true, LanguageException.class);
 	}
 
+	@Test
+	public void testInvalid2() {
+		TestConfiguration config = getTestConfiguration(TEST_INVALID2);
+		loadTestConfiguration(config);
+		runTest(true, LanguageException.class);
+	}
 }

src/test/scripts/functions/aggregate/TraceInvalid1.dml

@@ -0,0 +1,22 @@
+#-------------------------------------------------------------
+#
+# 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.
+#
+#-------------------------------------------------------------
+
+print(trace(rand(rows=100,cols=10)))

src/test/scripts/functions/aggregate/TraceInvalid2.dml

@@ -0,0 +1,22 @@
+#-------------------------------------------------------------
+#
+# 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.
+#
+#-------------------------------------------------------------
+
+print(trace(rand(rows=1000,cols=10)))