Any questions from newcomers on MQL4 and MQL5, help and discussion on algorithms and codes - page 1900

[Mihail Matkovskij]

JRandomTrader a ring buffer remembering the current position of the first element?

In Vitali's example, you can use this idea. But there is no way to avoid the loop (which is critical for it). In any case, we have to transfer the data from the ring buffer to the indicator buffer using the loop or the ArrayCopy function. And what will change?

[JRandomTrader]

Mihail Matkovskij #:

What a brilliant idea! Who came up with it and what is its practical application? I doubt it's used exclusively for sliding window charts...

Who came up with it - no end in sight, I think it's been reinvented many times, the idea is quite obvious.

I, for example, use it to calculate the moving average of data which is not stored in history, but only has an instantaneous value.

This has been used in data transmission since time immemorial.

[JRandomTrader]

Mihail Matkovskij #:

In Vitali's example, you can use this idea. But there is no way to avoid the loop (which is critical for it). In any case, we have to transfer the data from the ring buffer to the indicator buffer using the loop or the ArrayCopy function. And what would be different?

That a new value can be inserted and immediately copied from the desired place. The copy cycle remains, but there is no shift cycle.

[Mihail Matkovskij]

Vitaly Muzichenko #:

Checked it out, yes it's a good solution - I'm keeping it.

But I would still like to check howArrayCopy works.

With ArrayCopy, you can only transfer data from another array. But you cannot shift them. You can use a ring buffer and shift data from it... But how can you do it withArrayCopy if it has a circular motion... I don't understand. And, in principle, it doesn't need to be understood. The usual displacement using a loop is not so critical in terms of speed. At least, I don't know any faster. What can be faster, only assembler? Anyway, leave it as it is. It will work.

[Vitaly Muzichenko]

JRandomTrader #:

That a new value can be inserted and copied immediately from the correct place. The copy cycle remains, but there is no shift cycle.

Let's give an example, it would be in the

The code for upgrading is

[Vitaly Muzichenko]

Mihail Matkovskij #:

With ArrayCopy, you can only transfer data from another array. But it is not possible to shift them. You can use a circular buffer and transfer data from it... But how to do it withArrayCopy if it has a circular motion... I don't understand. And, in principle, it doesn't need to be understood. The usual displacement using a loop is not so critical in terms of speed. At least, I don't know any faster. What could be faster, assembler? Anyway, leave it as it is. It'll work.

Right now the code works, but the speed is questionable because of the loop.

What's it going to be?

I want to test some kitchens for arbitrage capability, the indicator will draw the difference of values, runs on a timer once every 100ms. Code execution delays are critical for this situation.

[Mihail Matkovskij]

JRandomTrader #:

This has been used in data transmission since time immemorial.

Convenient. You can't disagree with that. But as I said before, you should always consider how much data you can roll back.

[JRandomTrader]

Vitaly Muzichenko #:

Let's have an example, it'll be on topic

There isa code to upgrade

It won't work in this code because the indicator buffer lives independently of us and we don't organise a ring buffer in it - there's no way to explain this MT.

[Alexey Viktorov]

Mihail Matkovskij #:

With ArrayCopy, you can only transfer data from another array. But you cannot shift them.

Who told you this nonsense?

Read carefully how it is done.

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Any questions from newbies on MQL4 and MQL5, any help and discussion on algorithms and codes

Alexey Viktorov, 2022.02.13 18:21

In this code, you need to specify one array

int  ArrayCopy(
   void&        dst_array[],         // куда копируем
   const void&  src_array[],         // откуда копируем
   int          dst_start=0,         // с какого индекса пишем в приемник
   int          src_start=0,         // с какого индекса копируем из источника
   int          count=WHOLE_ARRAY    // сколько элементов
   );

Which index to write from and which one to copy depends on the array offset direction. So, if index 0 should always contain fresh, new data, copy from 0 and write from 1. Thus, values in index 0 and 1 will be identical, and afterwards a fresh value will be copied to 0.

And I doubt very much that ArrayCopy() has the same loop inside as the user one. So, having some array with a certain size, it is shifted by 1 on every tick and then copied into the indicator buffer that is displayed as a line...

[Vitaly Muzichenko]

JRandomTrader #:

It won't work in this code because the indicator buffer lives independently of us and we don't organize a ring buffer in it - there's no way to explain this MT.

I see.

Well, it works - let it work so far, no result yet, we must wait for our "friends" from the Pindos until the market opens, and it is not soon.

I will see what I can arbitrage.