code: public DoubleVector getRowVectorUnsafe(int row) {
          AtomicVector rowEntry = sparseMatrix.get(row);
          return (rowEntry == null)
              ? new CompactSparseVector(cols.get())
              : Vectors.immutable(Vectors.subview(rowEntry.getVector(), 
                                                  0, cols.get()));
      }
docs: Returns an immutable view of the row's data as a non-atomic vector, which
  may present an inconsistent view of the data if this matrix is being
  concurrently modified.  This method should only be used in special cases
  where the vector is being accessed at a time when the matrix (or this
  particular row) will not be modified.
  
  @param row the row whose values should be returned
  
  @return an unsafe, non-atomic view of the row's data