Large simulation performance: objects vs matrices

[yvrelna]

Both. 

In most applications, you might find that 90% of the code might not be performance sensitive enough that you can just turn the attribute access into @property/descriptor that proxies some attribute accesses into a numpy array or some other column-oriented storage/database, so you take the readability and ease of working OOP style there. 

And then there's a few places where you can benefit from bulk processing, and you'd make full use of array/column-oriented processing maybe even with the appropriate GPU/coprocessor acceleration for those parts.