code: public DMatrixIterator iterator(boolean rowMajor, int minRow, int minCol, int maxRow, int maxCol)
      {
          return new DMatrixIterator(this,rowMajor, minRow, minCol, maxRow, maxCol);
      }
docs: Creates a new iterator for traversing through a submatrix inside this matrix.  It can be traversed
  by row or by column.  Range of elements is inclusive, e.g. minRow = 0 and maxRow = 1 will include rows
  0 and 1.  The iteration starts at (minRow,minCol) and ends at (maxRow,maxCol)
  
  @param rowMajor true means it will traverse through the submatrix by row first, false by columns.
  @param minRow first row it will start at.
  @param minCol first column it will start at.
  @param maxRow last row it will stop at.
  @param maxCol last column it will stop at.
  @return A new MatrixIterator