error_functions.py 文件源码

def _eval_nseries(self, x, n, logx):
        # NOTE this is fairly inefficient
        from sympy import log, EulerGamma, Pow
        n += 1
        if self.args[0].subs(x, 0) != 0:
            return super(TrigonometricIntegral, self)._eval_nseries(x, n, logx)
        baseseries = self._trigfunc(x)._eval_nseries(x, n, logx)
        if self._trigfunc(0) != 0:
            baseseries -= 1
        baseseries = baseseries.replace(Pow, lambda t, n: t**n/n, simultaneous=False)
        if self._trigfunc(0) != 0:
            baseseries += EulerGamma + log(x)
        return baseseries.subs(x, self.args[0])._eval_nseries(x, n, logx)