Redefine derivative of a IndexedBase

[Lorenzo Monacelli]

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

[Kalevi Suominen]

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

[Lorenzo Monacelli]

Thanks a lot for the help!