From: mschuerch_at_[hidden]
Date: 2000-12-04 05:54:35
I would very much like a multidimensional array-class in boost. I'm
one of the ones, which have to use VC. Blitz++ is therefore no
alternative.
>
> I think this is part of a very important issue. Should we see an N
> dimensional array as a container of elements, or as a container of
N-
> 1 dimensional arrays? It really is both, but which view simplifies
> what we want to do with it? How do we want to access it? I think I
> ended up privileging the former view, that of a multidimensional
> array as a container of elements, structured in N dimensions, and I
> just used class SubArray as a way to get at the elements. I do not
> treat the various dimensions differently. When I resize the Array, I
> resize it all, I pass all the N dimensions of the Array to the
resize
> member function (naturally some of these can remain the same, and in
> any case, I preserve the existing elements where possible and
> desired). I do not see the first dimension as being different, and
> the result is that in my thinking:
>
> 1) size() returns the total number of elements in the N dimensional
> (sub)array, not the number of N-1 dimensional subarrays.
> 2) begin() returns an iterator that allows direct access to the
first
> element, not to the first N-1 dimensional array.
> 3) I wanted to maintain also a flat view of the underlying elements,
> so that I could apply algorithms and traverse the array
sequentially,
> following the order in which the elements are stored in memory.
>
I also think that a multidimensional array should be a flat container
with some mapping.
For the special case of N=2 this mapping mode should be compatible
with e.g. LinPack:
iflat = offset + i*istride + j*jstride
I think this is not possible with the second concept.
Some kind of expression templates would be the sugar of the library.
regards
Martin