- removed relaxed compression threshold

- added logging statement if it would be useful to implement compressed binary matrix-vector op with left true

Author: e-strauss

src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlockFactory.java

@@ -382,7 +382,7 @@ private void coCodePhase() {
 
 		logPhase();
 		// if cocode is estimated larger than uncompressed abort compression.
-		if(_stats.estimatedCostCoCoded > _stats.originalCost*2) {
+		if(_stats.estimatedCostCoCoded > _stats.originalCost) {
 			// abort compression
 			compressionGroups = null;
 			if(LOG.isInfoEnabled()) {
@@ -459,7 +459,7 @@ private void finalizePhase() {
 		_stats.compressedCost = costEstimator.getCost(res.getColGroups(), res.getNumRows());
 		_stats.setColGroupsCounts(res.getColGroups());
 
-		if(_stats.compressedCost > _stats.originalCost*2) {
+		if(_stats.compressedCost > _stats.originalCost) {
 			LOG.info("--dense size:        " + _stats.denseSize);
 			LOG.info("--original size:     " + _stats.originalSize);
 			LOG.info("--compressed size:   " + _stats.compressedSize);

src/main/java/org/apache/sysds/runtime/compress/lib/CLALibBinaryCellOp.java

@@ -421,9 +421,13 @@ private static MatrixBlock mvColCompressed(CompressedMatrixBlock m1, MatrixBlock
 
 		}
 
-		if(estNnzPerRow <= 2 && nCols <= 32 && op.fn instanceof ValueComparisonFunction && !left){
-            return k <= 1 ? binaryMVComparisonColSingleThreadCompressed(m1, m2, op) :
+		if(estNnzPerRow <= 2 && nCols <= 32 && op.fn instanceof ValueComparisonFunction){
+			if(!left)
+            	return k <= 1 ? binaryMVComparisonColSingleThreadCompressed(m1, m2, op) :
 					binaryMVComparisonColMultiCompressed(m1, m2, op);
+			else
+				LOG.debug("Compressed binary matrix-vector op left is not supported yet,\n" +
+						"fallback to generic binary matrix-vector op");
 		}
 		MatrixBlock ret = new MatrixBlock(nRows, nCols, shouldBeSparseOut, -1).allocateBlock();