why a[0][0].__mul__(a[0][0]) where a is np.array, gives 'missing 1 required positional argument'?
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The following code: --{--cut here-- #Purpose: # Demonstrate class with __add__ and __mult__ methods # to demonstrate shortestPath calculations. #OriginalSource: # ./shortestPath.py #References: # [1] http://www.marinamele.com/2014/04/modifying-add-method-of-python-class.html # [2] https://docs.scipy.org/doc/numpy/reference/c-api.types-and-structures.html#c... # [3] https://www.abebooks.com/book-search/title/graphs-networks/author/carre-bern... # Table 3.1, path algebra P2. # [4] https://docs.python.org/3/library/abc.html ########################################### import numpy as np from abc import ABCMeta, abstractmethod class PathAbstract(metaclass=ABCMeta): @abstractmethod def __repr__(self): pass @abstractmethod def __add__(self, other): pass @abstractmethod def __radd__(self, other): pass @abstractmethod def __mul__(self, other): pass @abstractmethod def __rmul__(self, other): pass class ShortestNull(PathAbstract): '''Null object in ShortestPath algebra[3]''' def __str__(self): return "<0>" def __repr__(self): return self.__str__() def __addreal__(self, other): return other def __add__(self, other): return other def __radd__(self, other): return other def __mulreal__(self, other): return self def __mul__(self, other): return self def __rmul__(self, other): return self class ShortestUnit(PathAbstract): '''Unit object in ShortestPath algebra[3]''' def __str__(self): return "<1>" def __repr__(self): return self.__str__() def __addreal__(self, other): return self def __add__(self, other): return self def __radd__(self, other): return self def __mulreal__(self, other): return other def __mul__(self, other): return other def __rmul__(self, other): return other class ShortestPath(PathAbstract): def __init__(self, distance): self.distance = distance def __str__(self): return "{0:4.1f}".format(self.distance) def __repr__(self): return self.__str__() def __addreal__(self, other): #paths composed of following shortest of self path or other path. min_dist=min(self.distance,other.distance) return ShortestPath(min_dist) def __add__(self, other): #paths composed of following shortest of self path or other path. if(other == 0): n=ShortestNull() return n.__addreal__(self) else: return other.__addreal__(self) def __radd__(self, other): return self.__add__(other) def __mulreal__(self, other): #path composed of self path followed by other path. min_dist=self.distance+other.distance return ShortestPath(min_dist) def __mul__(self, other): return other.__mulreal__(self) def __rmul__(self, other): return other.__mulreal__(self) d0=ShortestNull() d1=ShortestUnit() d2=ShortestPath(3) d3=ShortestPath(6) print(' d0=',d0,' d1=',d1,' d2=',d2,' d3=',d3) print(' type(d0)=',type(d0).__name__) d4=d0+d2+d3 print('d4=',d4) d5=d2*d3 print('d5=',d5) d6=d0*d2 print('d6=',d6) d7=d1*d2 print('d7=',d7) d8=d2*d0 print('d8=',d8) d9=d2*d1 print('d9=',d9) a=np.array([[ShortestNull,ShortestPath(12)],[ShortestPath(12),ShortestNull()]],dtype=object) print('a=',a,sep='\n') print('a[0]=',a[0],sep='\n') print('a[0][0]=',a[0][0],sep='\n') #a00mul=a[0][0]*a[0][0] a00mul=a[0][0].__mul__(a[0][0]) print('a00mul=',a00mul,sep='\n') #at=a.transpose() #print('at=',at,sep='\n') #aat=a.dot(at) print('aat=',aat,sep='\n') #mp=np.matmul(a,at)#this gives error about Object arrays not supported. #print('mp=',mp) --}--cut here-- When run by make, gives this result: --{--cut here-- make -k python3 shortestPathABC.py d0= <0> d1= <1> d2= 3.0 d3= 6.0 type(d0)= ShortestNull d4= 3.0 d5= 9.0 d6= <0> d7= 3.0 d8= <0> d9= 3.0 a= [[<class '__main__.ShortestNull'> 12.0] [12.0 <0>]] a[0]= [<class '__main__.ShortestNull'> 12.0] a[0][0]= <class '__main__.ShortestNull'> Traceback (most recent call last): File "shortestPathABC.py", line 123, in <module> a00mul=a[0][0].__mul__(a[0][0]) TypeError: __mul__() missing 1 required positional argument: 'other' Makefile:7: recipe for target 'all' failed make: *** [all] Error 1 --}--cut here-- I don't understand why. Apparently, a[0][0] is not a ShortestNull because otherwise, the .__mul__ would have the positional argument, 'other' equal to a[0][0]. What am I missing? TIA. -regards, Larry
participants (3)
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Larry Evans
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Robert Kern
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Sebastian Berg