[Numpy-discussion] Segmentation fault

Anne-Sophie Sertier sertier@biomserv.univ-lyon1...
Thu Apr 17 06:04:24 CDT 2008


Thanks a lot for your answer ! I will try another way !

Anne-Sophie

David Cournapeau a écrit :
> David Cournapeau wrote:
>> Unless you are executing this on a gigantic computer, this won't work 
>> very well: you are asking to create an array which has ~ 2e5^2 elements, 
>> that is around 40 Gb.
>>
>> There is a bug, but the bug happens at the above line: the zeros call 
>> did not fail whereas it should have. It is likely caused because the 
>> number of elements cannot fit into a 32 bits integers, which means it 
>> overflows:
>>
>> import numpy as np
>> n , m = 1e5,1e5
>> a = np.zeros((n, m), np.int8)
>> assert a.size == n * m
>>
>> Will raise an assertion error (n * m is just big enough to not fit into 
>> a 32 bits integer in this case).
>>   
> 
> I forgot to add: this is a bug in numpy, you should not get a 
> segmentation fault, but it would not work anyway (because you are asking 
> for a too big array) :)
> 
> cheers,
> 
> David
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> 

-- 
Anne-Sophie Sertier, Doctorante monitrice
UMR 5558, Laboratoire de Biométrie et Biologie Evolutive
Université Lyon1, bât G. Mendel 2è étage
43 bd du 11 novembre 1918
69622 Villeurbanne cedex
France

Tel: 04 26 23 44 76


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