code: public DoubleVector getRowVector(int row) {
          DoubleVector v = getRow(row, -1, false);
          // If no row was currently assigned in the matrix, then return an empty
          // vector in its place.  Otherwise, return a view on top of the vector
          // with its current length
          return (v == null) 
              ? new CompactSparseVector(cols.get())
              : Vectors.subview(v, 0, cols.get());
      }
docs: {@inheritDoc} The length of the returned row vector reflects the size of
  matrix at the time of the call, which may be different from earlier calls
  to {@link #columns()}.