docs: public static Matrix pascal(int size)
      {
          if(size <= 0 )
              throw new ArithmeticException();
          DenseMatrix P = new DenseMatrix(size, size);
          RowColumnOps.fillRow(P, 0, 0, size, 1.0);
          RowColumnOps.fillCol(P, 0, 0, size, 1.0);
          for(int i = 1; i < size; i++)
              for(int j = 1; j < size; j++)
                  P.set(i, j, P.get(i-1, j) + P.get(i, j-1));
          return P;
      }