Sorry: I forgot that this function got called thousands of times. I
guess in that case calling the size() function might result in some
allocation which would then get magnified by the number of calls. (Am I on
the right track?)
On Thursday, January 8, 2015 at 7:19:52 PM UTC-8, Petr Krysl wrote:
>
> Andreas,,
>
> Good point about the global scope. What I was really trying to understand
> was this observation:
>
> - function getconn!{T<:FESet}(self::T,conn::JFIntMat,j::JFInt)
> 5959808 for i=1:size(self.conn,2)
> 0 conn[i]=self.conn[j,i];
> - end
> 0 return self
> - end
>
> Isn't the size here in the local context, and also of a definite type?
>
> Petr
>
> On Thursday, January 8, 2015 at 7:09:35 PM UTC-8, Andreas Noack wrote:
>>
>> The reason is the usual global variable problem. Because n is global the
>> type is not inferred well and the loop is therefore not well optimized.
>> This doesn't happen in local scope e.g.
>>
>> julia> let
>>
>> m = 1000000
>>
>> @allocated for i = 1:m end
>>
>> end
>>
>> 0
>>
>> and it can also be avoided if you specify the type in the loop range
>>
>> julia> @allocated for i = 1:n::Int
>>
>> end
>>
>> 0
>>
>> 2015-01-08 22:02 GMT-05:00 Petr Krysl <[email protected]>:
>>
>>> julia> a=rand(1000000);
>>>
>>> julia> n=length(a);
>>>
>>> julia> @allocated for j=1:n
>>> end
>>> 63983688
>>>
>>> 64 MB to run this loop? Is that expected?
>>>
>>> Thanks for any insight.
>>>
>>> Petr
>>>
>>
>>
