debug alen/blen replacement on vector-vector primitives

Author: Twolvero

src/main/java/org/apache/sysds/hops/codegen/cplan/CNodeBinary.java

@@ -191,7 +191,7 @@ public String codegen(boolean sparse, GeneratorAPI api) {
 							(_type == BinType.VECT_MATRIXMULT ? varj : varj + ".vals(0)")) :
 							_inputs.get(j).getDataType() == DataType.MATRIX ? (api == GeneratorAPI.JAVA ? varj : varj + ".vals(0)") : varj);
 
-				tmp = tmp.replace("%SLEN"+(j+1)+"%", varj.startsWith("STMP") ? varj+".size()" : j ==  0 ? "alen" : "blen");
+				tmp = tmp.replace("%SLEN"+(j+1)+"%", varj.startsWith("STMP") ? varj+".size()" : varj.startsWith("a") ? "alen" : "blen");
 
 				//replace start position of main input
 				tmp = tmp.replace("%POS"+(j+1)+"%", (_inputs.get(j) instanceof CNodeData