IndexedBase has no `__init__` method of its own. It inherits
`object.__init__` that accepts no arguments and does nothing. Instead,
IndexedBase has a `__new__` method that accepts arguments. The custom class
will automatically inherit it. It is not necessary to define `__init__` at
all. As to 2), I believe that your way is correct.
Kalevi Suominen
On Tuesday, March 3, 2020 at 9:42:14 AM UTC+2, Lorenzo Monacelli wrote:
>
> Dear all,
> I am manipulating an IndexedBase object, and I would like to modify its
> behavior when differentiated.
>
> I thought to do something like this:
> class custom(sy.IndexedBase):
> def __init__(self, *args, **kwargs):
> sy.IndexedBase.__init__(self, *args, **kwargs)
>
> def diff(self, *args):
> # Do some stuff
> pass
>
> However, when I initialize the object:
> b = custom("b")
>
> It gives the error:
> object.__init__() takes no arguments
>
> However, it works if I do:
> b = sy.IndexedBase("b")
>
>
> I have two questions:
> 1) How can I create an object derivated from IndexedBase?
> 2) Is my way of doing correct to redefine the behaviour of the derivative?
> (It must work if I derivate a whole expression that contains the object)
>
> Thanks for your attention,
> Bests,
> Lorenzo
>
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