Thread: What would be the best way to name these typedefs?

Originally Posted by laserlight

Did you really find the occasional reallocation due to expansion of vector to be a bottleneck, in general?

Since you asked about vector in general, not about vector of strings, yes, I was forced to write a memory allocator which prevented fragmentation. The idea was common and simple, it was using larger chunks for small and fixed size memory blocks. Deque could quickly acquire specified block of memory (in logarithmic time), while vector had not only to copy data but also use slower new/delete as it grew in size.

I am arguing that you must have a reason for it, such as inserting at the beginning of a vector.

This, along with other benefits, is why I prefer deque as a general-purpose container for strings.

Originally Posted by kmdv

Since you asked about vector in general, not about vector of strings, yes, I was forced to write a memory allocator which prevented fragmentation. The idea was common and simple, it was using larger chunks for small and fixed size memory blocks. Deque could quickly acquire specified block of memory (in logarithmic time), while vector had not only to copy data but also use slower new/delete as it grew in size.

It sounds like vector was a poor choice of a container in that situation.

Well no, I did not say it was a radical difference for vector vs deque. Only that deque would be slower. IIRC.

He asked about any problems with vector, thus I gave a specific problem.
It's individual expierience with containers. I had some bad experiences with vector expanding and memory fragmentation, and I will keep using deque for strings unless I have a reason, since I think it's just unnecessary to use vector. Since we have no specific problem, I can't see any point in continuing this.

Originally Posted by Elysia

Well no, I did not say it was a radical difference for vector vs deque. Only that deque would be slower. IIRC.

Sorry for continuing, but you can't just say that deque would be slower. You can often push data, and access it very rarely. Vector has yet another problem - reallocation will not happen if you remove 95% of elements, in deque the unused memory can be freed.

Originally Posted by kmdv

Sorry for continuing, but you can't just say that deque would be slower. You can often push data, and access it very rarely. Vector has yet another problem - reallocation will not happen if you remove 95% of elements, in deque the unused memory can be freed.

And you can't say a vector is slower. It all depends on how and where you use it.
The only difference between us is the standard container we use. I use vector, you use deque.
I simply don't feel it's worth the difference to switch over to deque due to strings because I cannot put forth a good enough theoretical guess that it will be faster.
I would simply have to measure performance in my program if I needed it, and choose based on that.

Originally Posted by whiteflags

So, by saying this...
you either mean to patronize me, by assuming I have no idea what asymptotic notation is for,

Absolutely not. My comments were based on the fact that you understood what asymptotic notation is. We are both programmers.

...or you were saying that there was a radical difference between the two algorithms we were comparing. I'm sorry I was wrong, but I do not like the alternative interpretation any better. Saying the difference was negligible is a safe statement, unless you are prepared to dream up a situation where the difference in access time between vector and deque is a bottleneck.

The thing is that that was a general statement. Not a comparison with vector and deque.
Which was kind of my point. Of many, I guess.

The performance between a deque and vector is very similar (unless you count inserting at the beginning of a vector), that the Big-oh times for handling strings in a deque and vector would be the same. Therefore, I cannot make a very good guess as to which would be faster for my usage of strings. Therefore, I would not bother switching over to a deque unless I hit performance constraints in my program.

Sorry if I come off as rude or patronizing.