fix threadpool allocation in RMM decompression

Author: Baunsgaard

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

@@ -237,7 +237,7 @@ private static MatrixBlock decompressExecute(CompressedMatrixBlock cmb, int k) {
 			if(ret.isInSparseFormat()) 
 				decompressSparseSingleThread(ret, filteredGroups, nRows, blklen);
 			else 
-				decompressDenseSingleThread(ret, filteredGroups, nRows, blklen, constV, eps, nonZeros, overlapping);
+				decompressDenseSingleThread(ret, filteredGroups, nRows, blklen, constV, eps, overlapping);
 		}
 		else if(ret.isInSparseFormat()) 
 			decompressSparseMultiThread(ret, filteredGroups, nRows, blklen, k);
@@ -294,7 +294,7 @@ private static void decompressSparseSingleThread(MatrixBlock ret, List<AColGroup
 	}
 
 	private static void decompressDenseSingleThread(MatrixBlock ret, List<AColGroup> filteredGroups, int rlen,
-		int blklen, double[] constV, double eps, long nonZeros, boolean overlapping) {
+		int blklen, double[] constV, double eps, boolean overlapping) {
 
 		final DenseBlock db = ret.getDenseBlock();
 		final int nCol = ret.getNumColumns();
@@ -308,21 +308,19 @@ private static void decompressDenseSingleThread(MatrixBlock ret, List<AColGroup>
 		}
 	}
 
-	// private static void decompressDenseMultiThread(MatrixBlock ret, List<AColGroup> groups, double[] constV, int k,
-	// boolean overlapping) {
-	// final int nRows = ret.getNumRows();
-	// final double eps = getEps(constV);
-	// final int blklen = Math.max(nRows / k, 512);
-	// decompressDenseMultiThread(ret, groups, nRows, blklen, constV, eps, k, overlapping);
-	// }
-
-	protected static void decompressDenseMultiThread(MatrixBlock ret, List<AColGroup> groups, double[] constV,
+	public static void decompressDense(MatrixBlock ret, List<AColGroup> groups, double[] constV,
 		double eps, int k, boolean overlapping) {
 
 		Timing time = new Timing(true);
 		final int nRows = ret.getNumRows();
 		final int blklen = Math.max(nRows / k, 512);
-		decompressDenseMultiThread(ret, groups, nRows, blklen, constV, eps, k, overlapping);
+		if( k > 1)
+			decompressDenseMultiThread(ret, groups, nRows, blklen, constV, eps, k, overlapping);
+		else
+			decompressDenseSingleThread(ret, groups, nRows, blklen, constV, eps, overlapping);
+		
+		ret.recomputeNonZeros(k);
+		
 		if(DMLScript.STATISTICS) {
 			final double t = time.stop();
 			DMLCompressionStatistics.addDecompressTime(t, k);

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

@@ -189,15 +189,8 @@ private static MatrixBlock RMM(CompressedMatrixBlock m1, MatrixBlock that, int k
 			constV = mmTemp.isEmpty() ? null : mmTemp.getDenseBlockValues();
 		}
 
-		final Timing time = new Timing(true);
-
 		ret = asyncRet(f);
-		CLALibDecompress.decompressDenseMultiThread(ret, retCg, constV, 0, k, true);
-
-		if(DMLScript.STATISTICS) {
-			final double t = time.stop();
-			DMLCompressionStatistics.addDecompressTime(t, k);
-		}
+		CLALibDecompress.decompressDense(ret, retCg, constV, 0, k, true);
 
 		return ret;
 	}