def positive_roots(self):
        """
        This method generates all the positive roots of
        A_n.  This is half of all of the roots of D_n
        by multiplying all the positive roots by -1 we
        get the negative roots.

        Examples
        ========

        >>> from sympy.liealgebras.cartan_type import CartanType
        >>> c = CartanType("A3")
        >>> c.positive_roots()
        {1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
                5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
        """

        n = self.n
        posroots = {}
        k = 0
        for i in range(0, 1-n):
            for j in range(i+1, n):
               k += 1
               posroots[k] = self.basic_root(i, j)
               k += 1
               root = self.basic_root(i, j)
               root[j] = 1
               posroots[k] = root
        return posroots
dataset/ETHPy150Open sympy/sympy/sympy/liealgebras/type_d.py/TypeD.positive_roots/swapped operands of `-`