'Return indices of maximum elements along an axis.
Implicit zero elements are also taken into account. If there are
several maximum values, the index of the first occurrence is returned.
Parameters
axis : {-2, -1, 0, 1, None}, optional
Axis along which the argmax is computed. If None (default), index
of the maximum element in the flatten data is returned.
out : None, optional
This argument is in the signature *solely* for NumPy
compatibility reasons. Do not pass in anything except for
the default value, as this argument is not used.
Returns
ind : np.matrix or int
Indices of maximum elements. If matrix, its size along `axis` is 1.'

def argmax(self, axis=None, out=None):

    return self._arg_min_or_max(axis, out, np.argmax, np.greater)
