Re: [eigen] Malloc-free dynamic matrices

[ Thread Index | Date Index | More Archives ]

2010/3/2 leon zadorin <leonleon77@xxxxxxxxx>:
> On 3/3/10, leon zadorin <leonleon77@xxxxxxxxx> wrote:
>> On 3/3/10, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
>>> 2010/3/2 Márton Danóczy <marton78@xxxxxxxxx>:
>> [...]
>>>> The only API changes are a new option NeverRealloc (the name is maybe
>>>> not the best) and a method reserve(int size) that allocates the
>>>> memory. Then, a Matrix<Scalar, Dynamic, Dynamic, NeverRealloc> keeps
>>>> track of its allocated size via the member variable m_size and each
>>>> mat.resize(rows, cols) only changes two ints instead of actually
>>>> allocating memory. If rows*cols < m_size, an assertion error is
>>>> raised.
>> [...]
>>> approach... my main concern right now is that it's touching and
>>> complexifying a few very central places in Eigen, whereas the use case
>>> is very special. For that reason I wonder if this should rather be
>>> implemented as a new separate variant of the Matrix class itself...
>> And if it is a special/rare case usage, would it not be possible to
>> already achieve this behavior with a custom pre-allocated block of
>> memory and then instead of using matrix type simply using the
>> object(s) of Map<> type?
>> The "mapped" matricies would not need explicit resizing in the first
>> place... and reserving of the max size is simply done at allocation of
>> the very original memory slab -- as per current API and it's
>> capabilities?
> To clarify -- I'm getting at saying that one may not need patching
> anything in eigen in the first place, and by simply using the
> already-existing API of Map<> objects one could achieve what the
> original poster wanted :-)

Yes, that sounds like a very good idea. It may require minor API
additions to class Map to make it convenient for Marton, but that's
still much lighter than the proposed patch.


>> I suppose an adapter pattern may be deployed to create custom class --
>> but it's internals would/could still rely on the Map<> semantics...
>> Kind regards
>> Leon.

Mail converted by MHonArc 2.6.19+