How can I draw a zigzag?

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A little explanation:
I made fractal based calculations using High and Low data which I modified a bit.
As a result, I have a series of tops and bottoms, for example, taking into account the rules I set for 500 candles backwards from the current price.

double "Price Low" [0.71, 0.72, 0.695, 0.63]....
int "Price Low Index" [4, 11, 19, 24] (The indices of the elements of the Price Low are ordered from the right to the left of the graph. 0 is like the current price..)
double "Price High" (Peak Prices like Price Low)
int "Price High Index"
double "Total Price" (If an element of this array is Price High, the next element must be Price Low, sorted... )
int "Total Index" (And its indices)

I looked at the Zigzag indicator a bit to see how I can do it, but there are different situations. Now how can I draw a zigzag with the arrays I have in this hand?


For example:

#property indicator_chart_window
#property indicator_buffers 2
#property indicator_plots   1


#property indicator_label1  "ZigZag"
#property indicator_type1   DRAW_SECTION
#property indicator_color1  clrRed
#property indicator_style1  STYLE_SOLID
#property indicator_width1  1

double low[];
int lowindex[];
double high[];
int highindex[];
double total[];
int totalindex[];

//Am I supposed to create two sequences like this and assign the highs to one and the lows to the other?
double forZigzagHigh[];
double forZigzagLow[];


void OnInit()
  {

   SetIndexBuffer(0,forZigzagHigh,INDICATOR_DATA);
   SetIndexBuffer(1,forZigzagLow,INDICATOR_CALCULATIONS);

  }
 

I suppose you expect it to go from one Fractal to the next... But what is the problem right now, what is displayed?

Look, to use DRAW_SECTION you need to have all the points to be drawn in one buffer, so in the original zigzag you have one high buffer, one low buffer. These two are INDICATOR_CALCULATIONS, but not drawn.

Then there is another buffer which contains all the highs and lows (minus some) and this one is INDICATOR_DATA which means it is drawn. And the rest of preliminary and initiation stuff has to stay as it is, especially EMPTY_VALUE stuff from zigzags OnInit. So have the Fractal Buffers be INDICATOR_CALCULATIONS.

 
guga19:
A little explanation:
I made fractal based calculations using High and Low data which I modified a bit.
As a result, I have a series of tops and bottoms, for example, taking into account the rules I set for 500 candles backwards from the current price.

double "Price Low" [0.71, 0.72, 0.695, 0.63]....
int "Price Low Index" [4, 11, 19, 24] (The indices of the elements of the Price Low are ordered from the right to the left of the graph. 0 is like the current price..)
double "Price High" (Peak Prices like Price Low)
int "Price High Index"
double "Total Price" (If an element of this array is Price High, the next element must be Price Low, sorted... )
int "Total Index" (And its indices)

I looked at the Zigzag indicator a bit to see how I can do it, but there are different situations. Now how can I draw a zigzag with the arrays I have in this hand?


For example:

i have a zigzag indicator that i converted from tradingview.

not sure if it will help you.

but don't ask me to explain the code, i'm not good in explanation.

Files:
zz.mq4  5 kb
 
Tobias Johannes Zimmer #:

I suppose you expect it to go from one Fractal to the next... But what is the problem right now, what is displayed?

Look, to use DRAW_SECTION you need to have all the points to be drawn in one buffer, so in the original zigzag you have one high buffer, one low buffer. These two are INDICATOR_CALCULATIONS, but not drawn.

Then there is another buffer which contains all the highs and lows (minus some) and this one is INDICATOR_DATA which means it is drawn. And the rest of preliminary and initiation stuff has to stay as it is, especially EMPTY_VALUE stuff from zigzags OnInit. So have the Fractal Buffers be INDICATOR_CALCULATIONS.

I already have two separate price lists of highs and lows, these will be "INDICATOR_CALCULATIONS", and I have a total list, which is a combination of these two lists, which will be "INDICATOR_DATA" and I'll just draw this, right?

In short,

indicator_buffer 1

indicator_plots 1

--

Setindexbuffer(0,...)

plotindexsetintege...(0,...)

That's how it should be, right?

 
In MQL5 you declare all the buffers

indicator_buffers 3
indicator_plots 1

And initialise all three with SetIndexBuffer, there you can set DATA/CALCULATION

I think the data buffer has to be first (0).
But why don't you just copy the upper parts of the Examples ZigZag and change the calculation?
 
Tobias Johannes Zimmer #:
In MQL5 you declare all the buffers

indicator_buffers 3
indicator_plots 1

And initialise all three with SetIndexBuffer, there you can set DATA/CALCULATION

I think the data buffer has to be first (0).
But why don't you just copy the upper parts of the Examples ZigZag and change the calculation?
The current zigzag and fractal indicators do not give the results I want. I don't know exactly how they are calculated, but I get better results in my calculations. Also, it doesn't repaint. My main goal is to make an indicator that will find harmonic and other patterns. First I get the waves detected properly. It should give the prices in this "Total" array to one array and show only the price ranges that I want on the chart. (for example 500 candles) Actually, I did this with "Arrow" and tried to show it as a straight line in a zigzag shape.
 
guga19 #:
The current zigzag and fractal indicators do not give the results I want. I don't know exactly how they are calculated, but I get better results in my calculations. Also, it doesn't repaint. My main goal is to make an indicator that will find harmonic and other patterns. First I get the waves detected properly. It should give the prices in this "Total" array to one array and show only the price ranges that I want on the chart. (for example 500 candles) Actually, I did this with "Arrow" and tried to show it as a straight line in a zigzag shape.

Okay now I don't understand what you want to do any more. I mean it partly makes sense but doesn't quite add up. You mentioned in a previous post that you have two calculations buffers and one drawn buffer, so it sounds feasible to copy the head of ZZ from Examples/Indicators and build your own calculation formula below that.

Another thing is letting a for loop run across the last 500 bars of data buffer and have it gather all the ZZ points into an array. So you have the price differences and you can take the bar differences as well into another array. But this array can't have the same size as the data buffer. Because it doesn't contain the empty places.

(Edit) I think you did the latter one first. But that is not ideal for the functionality of indicator buffers. An Indicator buffer is a special kind of array that goes from bar zero to rates_total-1. When you initialise it as indicator data it is drawn automatically. The ZZ's Final buffer still contains a lot of zero values, but they are changed into EMPTY_VALUE, so they don't appear in the chart via PlotIndexSetDouble.

Might have a look here https://www.mql5.com/en/code/20524
ZigZag on Fractals
ZigZag on Fractals
  • www.mql5.com
ZigZag based on the Fractals indicator.
 

Its true ZigZag is not reliable for visual analysis done manually as you cannot see the repainting steps.

Usually in projects that require divergence or patterns its a headache to explain certain things expecially if 

the clients are coming with ideas from a youtuber .

But any way , laughs aside , there are 2 basic ways of going about it :

  • Measure by bars , lets call it barometry , where you require an amount of bars before and after the swing point that have not gone beyond its price.
  • Measure by points , lets call it tickometry , where you require an amount of points before and after the swing point of which the bars that make up the move have not gone beyond its price.

These terms are personal , so don't google them.

Tickometry by the way is probably what all those trend laser indicators use.
They measure the average confirming distance covered for a swing to be valid but , they are probably based on the historic snapshot of the zigzag which makes their 
algorithms vulnerable to unseen errors due to zigzag's repainting.

ZigZag is using a combination of both . It's mostly aimed at detecting swings fast and not slowing down the terminal with calculations.
It's a beautiful algorithm and it's indeed hard to explain.

If you go with 100% tickometry :
  • You will log swings when the left side and the right side have at least X amount of points and above.
  • You will also need to define what that size is , by atr or by reading higher timeframe bars .(i used to read 20 bars of the monthly chart and the average was then multiplied by a timeframe factor)
  • There will be a lot of swings missed because they won't be logged in low volatility
  • What is good about tickometry is you can go one way , and don't have to loop back to check , if i recall correctly.

If you go with 100% barometry :
  • There will be instances where you have a new high , you have not found a new low and you find a higher high again.If you want to not repaint you will have to interject a low in between those two points so that they remain in history but the code (or user) needs to know that the interjected low was not discovered like the rest of the points are.
  • You will also have to account for equal price swings , i.e a top being the same value across 3 bars .

As far as logging goes you can keep the swing points in the same array but point to the previous and next points in distance in bars , if you 
are logging them on the indicator buffers .

Finally while detecting patterns , regardless of your wave capture method , you will need to skip some points and even asign 
groups of them to a bigger encompassing leg .
 
Tobias Johannes Zimmer #:

Okay now I don't understand what you want to do any more. I mean it partly makes sense but doesn't quite add up. You mentioned in a previous post that you have two calculations buffers and one drawn buffer, so it sounds feasible to copy the head of ZZ from Examples/Indicators and build your own calculation formula below that.

Another thing is letting a for loop run across the last 500 bars of data buffer and have it gather all the ZZ points into an array. So you have the price differences and you can take the bar differences as well into another array. But this array can't have the same size as the data buffer. Because it doesn't contain the empty places.

(Edit) I think you did the latter one first. But that is not ideal for the functionality of indicator buffers. An Indicator buffer is a special kind of array that goes from bar zero to rates_total-1. When you initialise it as indicator data it is drawn automatically. The ZZ's Final buffer still contains a lot of zero values, but they are changed into EMPTY_VALUE, so they don't appear in the chart via PlotIndexSetDouble.

Might have a look here https://www.mql5.com/en/code/20524

Ok it's been a while and I fixed some things.

1) First of all, I have identified candles that are higher and lower than the candle before and after them within the candle range I have determined.

2) I did another elimination due to a problem

3) If there is a high then the following should be low. So it should be sequential. I eliminated consecutive lows and highs according to certain rule.

4) I kept at least 0.4% or more between high-low or low-high both points and eliminated the values.

5) I gave the remaining highs and lows to 2 separate series according to their indexes, I gave "zero" to places where there is no price.


I did each elimination with "ArrayRemove" then resized with "ArrayResize".


As a result I have

Up Price array

Up Index array

Down Price array

Down Index array

Total Price array

Total Index array


and two buffers (plotted)

up_dots

down_dots

Files:
Example.png  26 kb
 
Yes okay congratulations from your picture your calculations seem to work.

But it also looks like unnecessary copying back and forth. Since the Price and Index arrays are of no further use in this Indicator. 

You can only copy THE buffers with CopyBuffer.

I would rather say that later in an EA you could take the price and bar differences, so you can have the span and duration of up and down movements and the velocity at which price moves from one point to another.

Except maybe you have a different plan in mind.
 
Tobias Johannes Zimmer #:
Yes okay congratulations from your picture your calculations seem to work.

But it also looks like unnecessary copying back and forth. Since the Price and Index arrays are of no further use in this Indicator. 

You can only copy THE buffers with CopyBuffer.

I would rather say that later in an EA you could take the price and bar differences, so you can have the span and duration of up and down movements and the velocity at which price moves from one point to another.

Except maybe you have a different plan in mind.
I'll take your advice into consideration.  As it stands, when I "compile" it takes an average of 1200 msec, it seems like it's not very effective.  :) Because I'm going to code more harmonic structures, they have an extra load...
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