[Beowulf] Fortran Array size question

richard.walsh at comcast.net richard.walsh at comcast.net
Tue Nov 3 12:01:32 PST 2009


>----- Original Message ----- 
>From: "Prentice Bisbal" <prentice at ias.edu> 
>To: "Beowulf Mailing List" <beowulf at beowulf.org> 
>Sent: Tuesday, November 3, 2009 1:24:00 PM GMT -06:00 US/Canada Central 
>Subject: Re: [Beowulf] Fortran Array size question 
> 
>Greg Lindahl wrote: 
>> On Tue, Nov 03, 2009 at 01:17:02PM -0500, Prentice Bisbal wrote: 
>> 
>>> That's exactly the compiler I'm using, and it's failing at ~200 million 
>>> elements. I'm digging through the Intel documentation. Haven't found an 
>>> answer yet. 
>> 
>> Your bug report was incomplete: it really matters if the array is 
>> automatic or not, or if it's initialized. 
>> 
>You're right - I should have included a code snippet. It's not my code, 
>so I don't know if I can share all of it. Here's the line where the 
>problem occurs: 
> 
>dimension vstore(1:4,0:4,5000000,2),fstore(0:4,5000000,2) 
> 
>If he reduces the 5000000 to a smaller number, it compiles. As shown, he 
>gets this error: 
> 
>ifort adaptnew2.for 
>... 
>... 
>compilation aborted for adaptnew2.for (code 1) 


Prentice, 


I do not think the Fortran standard limits the size of one dimension 
in an array, although you can have only 7 dimensions. This to me must 
be a limit internal to their compiler. There may be an environmental variable 
to reset. I would try another Fortran (maybe gfortran) to see if you get similar 
behavior or find another (different) limit. 


Limits should really be operating system imposed based on the 
size of the address space. Intel says as much on the website 
describing their compiler. 


Regards, 


rbw 
Thrashing River Computing 
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