#!/usr/bin/env python
# coding: utf-8

# # Tutorial 06: Deriving Evolver and Driver classes
# 
# > Interactive online tutorial:
# > [![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/ubermag/micromagneticmodel/master?filepath=docs%2Fipynb%2Findex.ipynb)
# 
# In `micromagneticmodel` package, base classes `micromagneticmodel.Driver` and `micromagneticmodel.Evolver` are defined. Their purpose is to build individual evolvers and drivers in a particular micromagnetic calculator. In this tutorial, we will demonstrate some of their basic properties, on an example of a `micromagneticmodel.Driver` class. The behaviour of the `micromagneticmodel.Evolver` class is the same.
# 
# Let us derive `MyDriver` class. In order to define it, `_allowed_kwargs` list must be defined. It is a list of strings, which lists the kwargs which are allowed to be passed.

# In[1]:


import micromagneticmodel as mm

class MyDriver(mm.Driver):
    _allowed_kwargs = ['arg1', 'arg2']


# `Driver` class does not require any parameters to be passed at initialisation. If a keyword argument is from `_allowed_kwargs` list, it will be assigned as a class attribute. Otherwise, `AttributeError` will be raised.

# In[2]:


driver = MyDriver(arg1=1, arg2='value')


# The attributes are

# In[3]:


driver.arg1


# In[4]:


driver.arg2


# If we try to pass a keyword argument at initialisation, which is not in the `_allowed_kwargs` list, `AttributeError` is rased:

# In[5]:


try:
    driver = MyDriver(arg3=1)
except AttributeError:
    print('Exception raised.')


# The main driver method which must be implemented by a derived class is `drive`.

# In[6]:


try:
    driver.drive()
except NotImplementedError:
    print('Exception raised.')


# ## Other
# 
# Full description of all existing descriptors can be found in the [API Reference](https://micromagneticmodel.readthedocs.io/en/latest/?badge=latest).