Re: [Boost-users] multi-array and pdes

Subject: Re: [Boost-users] multi-array and pdes
From: Pierre-Andre Noel (noel.pierre.andre_at_[hidden])
Date: 2011-05-22 12:27:04

I forgot a detail: once you got your "cyclic_storage_order", you should make
a normal multi_array as usual then access it through a multi_array_ref that
uses "cyclic_storage_order".

On Sun, May 22, 2011 at 12:17 PM, Pierre-Andre Noel <
noel.pierre.andre_at_[hidden]> wrote:

> Hello Petros,
>
> I think that what you are looking for is a different storage order.
>
> Take a look at "boost/multi_array/storage_order.hpp". 3 classes are
> defined: general_storage_order, c_storage_order and fortran_storage_order.
>
> You need to make a "cyclic_storage_order" (or something like that) that
> receives an integer. When receiving zero, it should behave like
> c_storage_order. When receiving 1, everything should be permuted by 1 etc.
> This new class should inherit from general_storage_order. Use
> c_storage_order and fortran_storage_order as examples.
>
> Keep "ascending" true, only "ordering" has to be changed. A modulo should
> do it.
>
> Hope it helps,
>
> Pierre-André Noël
>
>
> On Sun, May 22, 2011 at 11:53 AM, petros <pmamales_at_[hidden]> wrote:
>
>> Hi Larry,
>> apologies, for not being clear.
>> Yes, MA is boost::multi_array. M, N, L are the dimensions
>> (this is only a "logical" statement, rather than a proper code snippet).
>> I think I have pretty much sorted out the calling practices wrt multi-aray
>> and looking
>> for if certain functionality exists.
>> My problem amounts to having a view that would allow for the permutation
>> (if not rotation) of axes.
>> As I begun to explain, the operator splitting methods decompose a problem
>> in N dimensions
>> into N 1-dimensional problems.
>> The problem itself is stated, though, in a certain reference system (this
>> means that the discretized
>> operators (stencils) and the boundary conditions are expressed in terms of
>> these boundary conditions.
>> However, the linear equation systems that are produced, are in tridiagonal
>> form, only in one of these steps
>> ( the first step of the 1-D problems ). Otherwise it produces a
>> block-banded system of equations, that can
>> be reduced back to the familiar tridiagonal ( conceptually), through axes
>> permutation (or rotation).
>> If one things in terms of the 2D problem analog, while conceptually it
>> would amount to exchange the two axes,
>> in matrix form, and because of the storage alignment it would involve a
>> much bigger operation. Since, these
>> operators/systems are created from the problem, it would be very nice to
>> have this view functionality to exploit
>> for keeping the storage of the operators in the desired form.
>>
>> I hope this is clearer now - don't mean to drag you into my problem.
>> Thank you for your response,
>> Petros
>>
>>
>> -----Original Message----- From: Larry Evans
>> Sent: Sunday, May 22, 2011 10:43 AM
>> To: boost-users_at_[hidden]
>> Subject: Re: [Boost-users] multi-array and pdes
>>
>>
>> On 05/21/11 15:02, petros wrote:
>> Hi Petros,
>>
>> [snip]
>>
>>> Suppose then that I have a MA( M, N, L ):
>>>
>>
>> Please be more specific.  I assume:
>>
>>  MA means boost::multi_array
>>
>> however, I've no idea what M, N, and L are.  Could you please
>> explain further?
>>
>> -regards,
>> Larry
>>
>>
>> _______________________________________________
>> Boost-users mailing list
>> Boost-users_at_[hidden]
>> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>> _______________________________________________
>> Boost-users mailing list
>> Boost-users_at_[hidden]
>> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>>
>
>