weird chrono time about articles

[borissmidt]

I have been able to implement some iterators for my custom pointer vector but i still have the chrono timing bug.
But if the time is correct then a vector of pointers is faster than a vector from array sizes of 128. But i cannot really compare it to the other errors because of the timing error.

[borissmidt]

I have solved it by explicitly setting the duration to 0 .
The benchmarks of my wrapped pointer vector show that it is faster than a vector at random insert from size 128. i will soon run all the tests.
But i think the pointer vector could be faster if i could somehow pre allocate reserved space. for example with a memory pool but i geuss this is too complex for me now.

[wichtounet]

Hi,

Sorry about that. I've slightly changed the timing function, it should not have these weird numbers anymore. Could you check again ?

Yes, it is likely that if you reserve the memory in a single block, it will be faster because of very good data locality of the pointers.

[borissmidt]

yea i used the same solution aswell to solve the chrono problem. i have the results in, the ptr vector seems faster than a linked list. But i guess the vector implementation is verry naive since it only allocated on an incert like a linked list and i am certain it could be made faster with a memory pool instead like a vector or deque. So then the performance would probably be between a deque and vector. except the fill back. the graph is html but github doesn't support it.

graph.txt
here is the naive ptr vector implementation. i quess i learned a thing or two from using you highly templated benchmark.
pointer_vector.txt

[borissmidt]

Maybe in the future when i'm better at programming C++ i could program my own pointer vector where which uses an allocator to pre allocate a memory block for the container. So the container becomes less naive and has some capacity reserved.

[wichtounet]

If you use vector as an underlying implementation, you at least have memory reserve for the pointers, but indeed it would probably be faster to have a memory pool for the objects themselves, but this is not trivial work.

I don't get the difference between const_iterator and iterator in your implementation. You use *a in iterator (which seems correct) for operator and &a in const_iterator. Otherwise, it seems quite good 👍

[borissmidt]

Yea i should come back later to it if i ever need it. But i guess a ponter vector + memory pool is almost like a deque in its structure but with more direct acces.

But the iterators do not implement enough for the c++ sort method. and thank for the complement.

[wichtounet]

I'm closing this issue, please reopen if there are still problems with this.