more functions

src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupUncompressedArray.java

@@ -21,6 +21,7 @@
 
 import org.apache.sysds.runtime.compress.colgroup.indexes.IColIndex;
 import org.apache.sysds.runtime.frame.data.columns.Array;
+import org.apache.sysds.runtime.matrix.data.MatrixBlock;
 
 /**
  * Special sideways Compressed column group not supposed to be used outside of the compressed transform encode. 
@@ -37,4 +38,16 @@ public ColGroupUncompressedArray(Array<?> data, int id, IColIndex colIndexes){
 	}
 
 
+	@Override 
+	public int getNumValues(){
+		return array.size();
+	}
+
+
+	@Override
+	public long estimateInMemorySize(){
+		// not accurate estimate, but guaranteed larger.
+		return MatrixBlock.estimateSizeInMemory(array.size(),1,array.size()) + 80;
+	}
+
 }

src/main/java/org/apache/sysds/runtime/compress/colgroup/indexes/ColIndexFactory.java

@@ -126,7 +126,7 @@ else if(contiguous)
 			return ArrayIndex.estimateInMemorySizeStatic(nCol);
 	}
 
-	public static IColIndex combine(List<AColGroup> gs) {
+	public static IColIndex combine(List<? extends AColGroup> gs) {
 		int numCols = 0;
 		for(AColGroup g : gs)
 			numCols += g.getNumCols();

src/main/java/org/apache/sysds/runtime/transform/encode/CompressedEncode.java

@@ -620,6 +620,7 @@ private void combineUncompressed(CompressedMatrixBlock mb) {
 	}
 
 	private AColGroup combine(List<ColGroupUncompressedArray> ucg) {
+		IColIndex combinedCols = ColIndexFactory.combine(ucg);
 		throw new NotImplementedException("Should combine " + ucg.size());
 	}