[Boost-users] Multi_array: A "proper" iterator over a N>1 Multi_array?

From: Greg Link (link_at_[hidden])
Date: 2006-04-25 19:04:15

I'm using multi_array types as containers for some things I'm working  
on, and the number of dimensions can get quite large - often over 7,  
sometimes as high as 11. I'd like to do things such as initialize  
these multi_arrays, access all elements within them, and other such  
'reasonable' operations.

Thing is, the only iterator interface to multi_array returns a  
reference to the nested containers. Thus, to iterate over all sub- 
elements, I'm forced to have 7-11 nested for-loops to iterate over  
the entire thing.

Is there an existent means of simply iterating over the entire set of  
data in the multi_array? Has anyone implemented such a thing, or is  
such a thing something to be desired within boost::multi_array?  It  
seems like such a iterator would be especially useful if also  
implemented/supported within subgroups, allowing the user to define  
sub-ranges of the multi_array, then iterate over each element  
therein, without having to worry about dimensionality, et cetera.

Any thoughts, ideas, or pointers to how to easily (without tons of  
code) iterate over an 11-dimensioned object is appreciated.

In conclusion then, I've got two problems. One is "How can I simplify  
my each-element access to a high-dimensional multi_array", and the  
second is "Should there be a direct-to-element iterator in  
multi_array, and does the documentation adequately address the issue  
of whether or not an iterator points to elements directly or to a sub- 
graph?"

Thanks for your time and troubles,

- Greg Link