joblib.Memoryキャッシュの使用方法Pythonクラスのメンバ関数の出力

Question

joblib.Memoryライブラリを使用してクラスのメンバ関数の出力をキャッシュしたいと思います。ここではサンプルコードは次のとおりです。

import joblib 
import numpy as np 

mem = joblib.Memory(cachedir='/tmp', verbose=1) 


@mem.cache 
def my_sum(x): 
    return np.sum(x) 


class TestClass(object): 
    def __init__(self): 
     pass 

    @mem.cache 
    def my_sum(self, x): 
     return np.sum(x) 


if __name__ == '__main__': 
    x = np.array([1, 2, 3, 4]) 
    a = TestClass() 
    print a.my_sum(x) # does not work 
    print my_sum(x) # works fine 

しかし、私は次のエラーを取得する：

/nfs/sw/anaconda2/lib/python2.7/site-packages/joblib/memory.pyc in _get_output_dir(self, *args, **kwargs) 
    512    of the function called with the given arguments. 
    513   """ 
--> 514   argument_hash = self._get_argument_hash(*args, **kwargs) 
    515   output_dir = os.path.join(self._get_func_dir(self.func), 
    516         argument_hash) 

/nfs/sw/anaconda2/lib/python2.7/site-packages/joblib/memory.pyc in _get_argument_hash(self, *args, **kwargs) 
    505  def _get_argument_hash(self, *args, **kwargs): 
    506   return hashing.hash(filter_args(self.func, self.ignore, 
--> 507           args, kwargs), 
    508        coerce_mmap=(self.mmap_mode is not None)) 
    509 

/nfs/sw/anaconda2/lib/python2.7/site-packages/joblib/func_inspect.pyc in filter_args(func, ignore_lst, args, kwargs) 
    228       repr(args)[1:-1], 
    229       ', '.join('%s=%s' % (k, v) 
--> 230          for k, v in kwargs.items()) 
    231       ) 
    232      ) 

ValueError: Wrong number of arguments for my_sum(self, x): 
    my_sum(array([1, 2, 3, 4]),) was called. 

は、メモリを使用して、クラスのメンバ関数をキャッシュするための方法や他のデコレータはありますか？

Answer 1

次の抜粋は、https://pythonhosted.org/joblib/memory.html#gotchas

caching methods: you cannot decorate a method at class definition, because when the class is instantiated, the first argument (self) is bound, and no longer accessible to the Memory object. The following code won’t work:

class Foo(object):

@mem.cache # WRONG 
def method(self, args): 
    pass 

The right way to do this is to decorate at instantiation time:

class Foo(object):

def __init__(self, args): 
    self.method = mem.cache(self.method) 

def method(self, ...): 
    pass