[SYSTEMDS-3919] Use SIMD Vector API in unary dense operations

This patch introduces SIMD vector operations in selected unary builtin
operations. However, the code-path is still disabled because experiments
on different hardware platforms showed inconclusive results.

Author: mboehm7

src/main/java/org/apache/sysds/runtime/functionobjects/Builtin.java

@@ -26,6 +26,9 @@
 import org.apache.sysds.runtime.DMLRuntimeException;
 import org.apache.sysds.runtime.DMLScriptException;
 
+import jdk.incubator.vector.DoubleVector;
+import jdk.incubator.vector.VectorSpecies;
+
 
 /**
  *  Class with pre-defined set of objects. This class can not be instantiated elsewhere.
@@ -46,14 +49,17 @@
 public class Builtin extends ValueFunction 
 {
 	private static final long serialVersionUID = 3836744687789840574L;
-	
+		
 	public enum BuiltinCode { AUTODIFF, SIN, COS, TAN, SINH, COSH, TANH, ASIN, ACOS, ATAN, LOG, LOG_NZ, MIN,
 		MAX, ABS, SIGN, SQRT, EXP, PLOGP, PRINT, PRINTF, NROW, NCOL, LENGTH, LINEAGE, ROUND, MAXINDEX, MININDEX,
 		STOP, CEIL, FLOOR, CUMSUM, ROWCUMSUM, CUMPROD, CUMMIN, CUMMAX, CUMSUMPROD, INVERSE, SPROP, SIGMOID, EVAL, LIST,
 		TYPEOF, APPLY_SCHEMA, DETECTSCHEMA, ISNA, ISNAN, ISINF, DROP_INVALID_TYPE, 
 		DROP_INVALID_LENGTH, VALUE_SWAP, FRAME_ROW_REPLICATE,
 		MAP, COUNT_DISTINCT, COUNT_DISTINCT_APPROX, UNIQUE}
 
+	private static final VectorSpecies<Double> SPECIES = DoubleVector.SPECIES_PREFERRED;
+	private static final int vLen = SPECIES.length();
+
 
 	public BuiltinCode bFunc;
 
@@ -197,6 +203,38 @@ else if (in < 0)
 				throw new DMLRuntimeException("Builtin.execute(): Unknown operation: " + bFunc);
 		}
 	}
+	
+	public long execute (double[] a, double[] c, int start, int end) {
+		long nnz = 0;
+		
+		//process rest or unsupported builtin codes
+		final int end2 = (bFunc==BuiltinCode.ABS || bFunc==BuiltinCode.SQRT)?
+			start+((end-start)%vLen) : end;
+		for( int i = start; i < end2; i++) {
+			c[i] = execute(a[i]);
+			nnz += (c[i] != 0) ? 1 : 0;
+		}
+		
+		nnz += (end-end2);
+		if( bFunc == BuiltinCode.ABS) {
+			for( int i = end2; i < end; i+=vLen ){
+				DoubleVector aVec = DoubleVector.fromArray(SPECIES, a, i);
+				DoubleVector cVec = aVec.abs();
+				nnz -= cVec.eq(0).trueCount();
+				cVec.intoArray(c, i);
+			}
+		}
+		else if(bFunc == BuiltinCode.SQRT ) {
+			for( int i = end2; i < end; i+=vLen ){
+				DoubleVector aVec = DoubleVector.fromArray(SPECIES, a, i);
+				DoubleVector cVec = aVec.sqrt();
+				nnz -= cVec.eq(0).trueCount();
+				cVec.intoArray(c, i);
+			}
+		}
+		return nnz;
+	}
+
 
 	@Override
 	public double execute (long in) {

src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixBincell.java

@@ -3278,10 +3278,17 @@ public Long call() throws Exception {
 				double[] avals = _a.values(_rl);
 				double[] cvals = _c.values(_rl);
 				int start = _a.pos(_rl), end = _a.pos(_ru);
-				for( int i=start; i<end; i++ ) {
-					cvals[i] = _op.fn.execute(avals[i]);
-					nnz += (cvals[i] != 0) ? 1 : 0;
-				}
+				
+				//TODO use of vector API inconclusive on different hardware
+				//if( _op.fn instanceof Builtin ) {
+				//	nnz += ((Builtin)_op.fn).execute(avals, cvals, start, end);
+				//}
+				//else {
+					for( int i=start; i<end; i++ ) {
+						cvals[i] = _op.fn.execute(avals[i]);
+						nnz += (cvals[i] != 0) ? 1 : 0;
+					}
+				//}
 			}
 			//generic dense-dense, including large blocks
 			else {