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From: Craig Rasmussen (crasmussen_at_[hidden])
Date: 2005-12-07 11:53:25


Begin forwarded message:

> From: Aleksandar Donev <adonev_at_[hidden]>
> Date: November 21, 2005 9:30:18 AM MST
> To: J3 <j3_at_[hidden]>
> Subject: (j3.2005) Re: Derived types according to MPI2
>
> Hello,
>
> Malcolm Cohen wrote:
>> Which just goes to show that the authors of MPI2 didn't understand
>> Fortran, since that is completely and utterly false in every sense
>> that matters.
> Yes, but the interesting thing is neither me nor Van were aware of
> what
> the standard actually allows in terms of derived types and the storage
> for the components, and presumably we know Fortran better. Can storage
> for the components be separated from the scalar derived type itself?
> This probably makes no visible difference for scalars, but for arrays
> it does. Again, I am asking about what STORAGE_SIZE for derived types
> should mean.
>
> Dan Nagle wrote:
>> Please be aware that the "external world" of the MPI standard
>> is really the virtual machine of the C standard.
> Yes, of course, I am certainly not proposing binding to hardware.
>
>> When defining a programming language, the "needless abstraction"
> I should have qualified with "some needless abstractions". Of course
> abstractions are good, especially when it does not matter to the user
> how something is done as long as it is done well. But if you want to
> pass an array of derived types to a parallel IO routine that is not
> compiled by your super-smart Fortran compiler that chooses to scatter
> the components across virtual-address space (yes, I mean virtual),
> then
> you do NOT want that abstraction.
>
> It is about choice. Leave preaching to the preachers. Programming is a
> profession for a reason---programmers are experienced and educated and
> understand the issues and don't need lectures on abstractions.
>
> Aleks