densebasic.py 文件源码

def dmp_degree(f, u):
    """
    Return the leading degree of ``f`` in ``x_0`` in ``K[X]``.

    Note that the degree of 0 is negative infinity (the SymPy object -oo).

    Examples
    ========

    >>> from sympy.polys.domains import ZZ
    >>> from sympy.polys.densebasic import dmp_degree

    >>> dmp_degree([[[]]], 2)
    -oo

    >>> f = ZZ.map([[2], [1, 2, 3]])

    >>> dmp_degree(f, 1)
    1

    """
    if dmp_zero_p(f, u):
        return -oo
    else:
        return len(f) - 1