Category Archives: EasyLanguage Object

Using a Dictionary to Create a Trading System

Dictionary Recap

Last month’s post on using the elcollections dictionary was a little thin so I wanted to elaborate on it and also develop a trading system around the best patterns that are stored in the dictionary.  The concept of the dictionary exists in most programming languages and almost all the time uses the (key)–>value model.  Just like a regular dictionary a word or a key has a unique definition or value.  In the last post, we stored the cumulative 3-day rate of return in keys that looked like “+ + – –” or “+ – – +“.  We will build off this and create a trading system that finds the best pattern historically based on average return.  Since its rather difficult to store serial data in a Dictionary I chose to use Wilder’s smoothing average function.

Ideally, I Would Have Liked to Use a Nested Dictionary

Initially, I played around with the idea of the pattern key pointing to another dictionary that contained not only the cumulative return but also the frequency that each pattern hit up.  A dictionary is designed to have  unique key–> to one value paradigm.  Remember the keys are strings.  I wanted to have unique key–> to multiple values. And you can do this but it’s rather complicated.  If someone wants to do this and share, that would be great.  AndroidMarvin has written an excellent manual on OOEL and it can be found on the TradeStation forums.  

Ended Up Using A Dictionary With 2*Keys Plus an Array

So I didn’t want to take the time to figure out the nested dictionary approach or a vector of dictionaries – it gets deep quick.  So following the dictionary paradigm I came up with the idea that words have synonyms and those definitions are related to the original word.  So in addition to having keys like “+ + – -” or “- – + -” I added keys like “0”, “1” or “15”.  For every  + or – key string there exists a parallel key like “0” or “15”.  Here is what it looks like:

–  –  –  –  = “0”
– – – + = “1”
– – + – = “2”

You can probably see the pattern here.  Every “+” represents a 1 and every “0” represent 0 in a binary-based numbering system.  In the + or – key I store the last value of Wilders average and in the numeric string equivalent, I store the frequency of the pattern.

Converting String Keys to Numbers [Back and Forth]

To use this pattern mapping I had to be able to convert the “++–” to a number and then to a string.  I used the numeric string representation as a dictionary key and the number as an index into an array that store the pattern frequency.  Here is the method I used for this conversion.  Remember a method is just a function local to the analysis technique it is written.

//Lets convert the string to unique number
method int convertPatternString2Num(string pattString) 
Vars: int pattLen, int idx, int pattNumber;
begin
	pattLen = strLen(pattString);
	pattNumber = 0;
	For idx = pattLen-1 downto 0 
	Begin
		If MidStr(pattString,pattLen-idx,1) = "+" then pattNumber = pattNumber + power(2,idx);
	end;
	Return (pattNumber);
end;
String Pattern to Number

This is a simple method that parses the string from left to right and if there is a “+” it is raised to the power(2,idx) where idx is the location of “+” in the string.  So “+  +  –  –  ” turns out to be 8 + 4 + 0 + 0 or 12.

Once I retrieve the number I used it to index into my array and increment the frequency count by one.  And then store the frequency count in the correct slot in the dictionary.

patternNumber = convertPatternString2Num(patternString); 
//Keep track of pattern hits
patternCountArray[patternNumber] = patternCountArray[patternNumber] + 1;
//Convert pattern number to a string do use as a Dictionary Key
patternStringNum = numToStr(patternNumber,2);
//Populate the pattern number string key with the number of hits
patternDict[patternStringNum] = patternCountArray[patternNumber] astype double;
Store Value In Array and Dictionary

Calculating Wilder’s Average Return and Storing in Dictionary

Once I have stored an instance of each pattern [16] and the frequency of each pattern[16] I calculate the average return of each pattern and store that in the dictionary as well.

//Calculate the percentage change after the displaced pattern hits
Value1 =  (c - c[2])/c[2]*100;
//Populate the dictionary with 4 ("++--") day pattern and the percent change
if patternDict.Contains(patternString) then
Begin
	patternDict[patternString] = (patternDict[patternString] astype double * 
	(patternDict[patternStringNum] astype double - 1.00) + Value1) / patternDict[patternStringNum] astype double;
end
Else
begin
	patternDict[patternString] = value1;
//	print("Initiating: ",patternDict[patternString] astype double);
end;
(pAvg * (N-1) + return) / N

When you extract a value from a collection you must us an identifier to expresses its data type or you will get an error message : patternDict[patternString] holds a double value {a real number}  as well as patternDict[patternStringNum] – so I have to use the keyword asType.  Once I do my calculation I ram the new value right back into the dictionary in the exact same slot.  If the pattern string is not in the dictionary (first time), then the Else statement inserts the initial three-day rate of return.

Sort Through All of The Patterns and Find the Best!

The values in a dictionary are stored in alphabetic order and the string patterns are arranged in the first 16 keys.  So I loop through those first sixteen keys and extract the highest return value as the “best pattern.”

//  get the best pattern that produces the best average 3 bar return
vars: hiPattRet(0),bestPattString("");
If patternDict.Count > 29 then
Begin
	index = patternDict.Keys;
	values = patternDict.Values; 
	hiPattRet = 0;
	For iCnt = 0 to 15
	Begin
		If values[iCnt] astype double > hiPattRet then
		Begin
			hiPattRet = values[iCnt] astype double ;
			bestPattString = index[iCnt] astype string;
		end;
	end;
//	print(Date," BestPattString ",bestPattString," ",hiPattRet:8:4," CurrPattString ",currPattString);
end;
Extract Best Pattern From All History

If Today’s Pattern Matches the Best Then Take the Trade

// if the current pattern matches the best pattern then bar next bar at open
If currPattString = BestPattString then buy next bar at open;
// cover in three days
If barsSinceEntry > 2 then sell next bar at open;
Does Today Match the Best Pattern?

If today matches the best pattern then buy and cover after the second day.

Conclusion

I didn’t know if this code was worth proffering up but I decided to posit it because it contained a plethora of programming concepts: dictionary, method, string manipulation, and array.  I am sure there is a much better way to write this code but at least this gets the point across.

Contents of Dictionary at End of Run

++++    0.06
+++-   -0.08
++-+    0.12
++--   -0.18
+-++    0.08
+-+-    0.40
+--+   -0.46
+---    0.34
-+++    0.20
-++-    0.10
-+-+    0.23
-+--    0.31
--++    0.02
--+-    0.07
---+    0.22
----    0.46
0.00  103.00
1.00  128.00
10.00  167.00
11.00  182.00
12.00  146.00
13.00  168.00
14.00  163.00
15.00  212.00
2.00  157.00
3.00  133.00
4.00  143.00
5.00  181.00
6.00  151.00
7.00  163.00
8.00  128.00
9.00  161.00
Contents of Dictionary

Example of Trades

Pattern Dictionary System

 

Code in Universum

//Dictionary based trading sytem
//Store pattern return
//Store pattern frequency
// by George Pruitt
Using elsystem.collections; 

vars: string keystring("");
vars: dictionary patternDict(NULL),vector index(null), vector values(null);
array: patternCountArray[100](0);

input: patternTests(8);
  
var: patternTest(""),tempString(""),patternString(""),patternStringNum("");
var: patternNumber(0);
var: iCnt(0),jCnt(0);
//Lets convert the string to unique number
method int convertPatternString2Num(string pattString) 
Vars: int pattLen, int idx, int pattNumber;
begin
	pattLen = strLen(pattString);
	pattNumber = 0;
	For idx = pattLen-1 downto 0 
	Begin
		If MidStr(pattString,pattLen-idx,1) = "+" then pattNumber = pattNumber + power(2,idx);
	end;
	Return (pattNumber);
end;


once begin 
   clearprintlog; 
   patternDict = new dictionary; 
   index = new vector;
   values = new vector;
end;   

//Convert 4 day pattern displaced by 2 days
patternString = ""; 
for iCnt = 5 downto 2
begin
    if(close[iCnt]> close[iCnt+1]) then
    begin
        patternString = patternString + "+";
    end
    else
    begin
        patternString = patternString + "-";
    end;
end;

//What is the current 4 day pattern
vars: currPattString("");
currPattString = "";

for iCnt = 3 downto 0
begin
    if(close[iCnt]> close[iCnt+1]) then
    begin
        currPattString = currPattString + "+";
    end
    else
    begin
        currPattString = currPattString + "-";
    end;
end;

//Get displaced pattern number
patternNumber = convertPatternString2Num(patternString); 
//Keep track of pattern hits
patternCountArray[patternNumber] = patternCountArray[patternNumber] + 1;
//Convert pattern number to a string do use as a Dictionary Key
patternStringNum = numToStr(patternNumber,2);
//Populate the pattern number string key with the number of hits
patternDict[patternStringNum] = patternCountArray[patternNumber] astype double;
//Calculate the percentage change after the displaced pattern hits
Value1 =  (c - c[2])/c[2]*100;
//Populate the dictionary with 4 ("++--") day pattern and the percent change
if patternDict.Contains(patternString) then
Begin
	patternDict[patternString] = (patternDict[patternString] astype double * 
	(patternDict[patternStringNum] astype double - 1.00) + Value1) / patternDict[patternStringNum] astype double;
end
Else
begin
	patternDict[patternString] = value1;
//	print("Initiating: ",patternDict[patternString] astype double);
end;
//  get the best pattern that produces the best average 3 bar return
vars: hiPattRet(0),bestPattString("");
If patternDict.Count > 29 then
Begin
	index = patternDict.Keys;
	values = patternDict.Values; 
	hiPattRet = 0;
	For iCnt = 0 to 15
	Begin
		If values[iCnt] astype double > hiPattRet then
		Begin
			hiPattRet = values[iCnt] astype double ;
			bestPattString = index[iCnt] astype string;
		end;
	end;
//	print(Date," BestPattString ",bestPattString," ",hiPattRet:8:4," CurrPattString ",currPattString);
end;
// if the current pattern matches the best pattern then bar next bar at open
If currPattString = BestPattString then buy next bar at open;
// cover in three days
If barsSinceEntry > 2 then sell next bar at open;
Pattern Dictionary Part II

 

 

 

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Using A Dictionary to Store Chart Patterns in EasyLanguage

Dictionary – Another Cool Collection Object

The dictionary object in EasyLanguage works just like a real dictionary.  It stores values that referenced by a key.  In a real-life dictionary, the keys would be words and the values would be the definitions of those words.

An Introduction

This little bit of code just barely skims the surface of the dictionary object, but it gives enough to get a nice introduction to such a powerful tool.  I am piggybacking off of my Pattern Smasher code here, so you might recognize some of it.

Object Delcaration

Like any of the objects in EasyLanguage a dictionary must be declared initially.

Using elsystem.collections; 
vars: dictionary patternDict(NULL),vector index(null), vector values(null);
input: patternTests(8);
var: patternTest(""),tempString(""),patternString("");
var: iCnt(0),jCnt(0);

once begin 
   clearprintlog; 
   patternDict = new dictionary; 
   index = new vector;
   values = new vector;
end; 
Declaring Objects

Here I tell the editor that I am going to be using the elsystem.collections and then a declare/define a dictionary named patterDict and two vectors:  index and values.  In the Once block, I create instances of the three objects.  This is boilerplate stuff for object instantiation.

 

for iCnt = 5 downto 2
begin
    if(close[iCnt]> close[iCnt+1]) then
    begin
        patternString = patternString + "+";
    end
    else
    begin
        patternString = patternString + "-";
    end;
end;
 
If patternString = "+++-" then Value99 = value99 + (c - c[2])/c[2];

if patternDict.Contains(patternString) then
Begin
//	print("Found pattern: ",patternString," 3-day return is: ", (c - c[2])/c[2]);
	patternDict[patternString] = patternDict[patternString] astype double + (c - c[2])/c[2];
end
Else
	patternDict[patternString] = (c - c[2])/c[2];
Build the Pattern String and Then Store It

 

The keys that index into the dictionary are strings.  In this very simple example, I want to examine all of the different combinations of the last four-bar closing prices.   Once the pattern hits up I want to accumulate the percentage change over the past three days and store that value in the location pointed to by the patternString key.

Notice how I displace the loop by three days (5-2 insteat of 3-0)?  I do this so I can compare the close at the end of the pattern with today’s close, hence gathering the percentage change.  Also, notice that I test to make sure there is an entry in the dictionary with the specific key string.  If there wasn’t already an entry with the key and I tried to reference the value I would get an error message – “unable to cast null object.”

Once I store the keys and values I can regurgitate the entire dictionary very simply.  The keys and values are stored as vectors.  I can simply assign these components of the dictionary to the two vectors I instantiated earlier.

If lastBarOnChart and patternDict.Count > 0 then
Begin
	index = patternDict.Keys;
	values = patternDict.Values; 
	For iCnt = 0 to patternDict.Count-1
	Begin
		print(index[iCnt] astype string," ",values[iCnt] astype double);
	end;
	print("Value99 : ",value99:8:4);
end;
Printing Out the Dictionary

And then I can simply index into the vectors to print out their contents.  I will add some more commentary on this post a little later this week.  I hope you find this useful.  And remember this will not work with MultiCharts.

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What’s Our Vector Victor – Tiptoeing in the EL Collections

Tired of Manipulating Arrays – Try a Vector and a Queue

Vectors:

An array like structure but are dynamic and have a plethora of tools at your disposal.  Arrays are cool and can be multi-dimensional and can be easily manipulated.  But they require a lot of forethought as to how much size to reserve for their implementation.  Now don’t think this is going to be an advanced EasyLanguage tutorial, because it’s really not.  Most of us TRS-80, Ti-99/4A, Vic-20 and Commodore 64 trained programmers of the early ’80s have not welcomed objects with open arms and that is really a mistake.  In this sense we are like cavemen – we have all of the rudimentary tools at our disposal and can create some really cool stuff and we can really understand what we are doing.  With time and effort, we can get to the same place as object-oriented programmers.  We just don’t like the concept of using other’s tools as much as we like using ours.  So if you aren’t classically trained in programming you may have an advantage when tieing into the objects of a programming language.  This little tutorial is a very brief glimpse into a whole different world of programming.  The beauty is you can combine “old school” programming with objects – even if you don’t understand how the objects are truly constructed.    I want to introduce the concept of the Vector and the Queue-  truly cool Swiss Army knives.  First the vector.  Let’s just jump into some of the code – it really is simple.

Object Instantiation – a long word for declaring variable:
Using elsystem.collections;

Vars: Vector opVector(NULL),
      Vector hiVector(Null),
      Vector loVector(Null),
      Vector clVector(Null),
      Vector barVector(Null),
      Queue timeStampQue(Null);
Once
Begin
	barVector = new Vector;
	opVector = new Vector;
	hiVector = new Vector;
	loVector = new Vector;
	clVector = new Vector;
	timeStampQue = new Queue;
end;
Instantiating and Declaring Vectors and Queue

You have to tell EasyLanguage you want to use some of the tools in the elsystem.collections.  You do this by simply tell it you are Using elsystem.collections.  The word collections is a catch-all for a bunch of different types of data structures.  Remember data structures are just programming constructs used to hold data – like an array.  All the variables that you declare in EasyLanguage are arrays – you just aren’t really aware of it.   When you index into them to get prior values then you become slightly aware of it.  In this portion of code, I create five vectors and one queue and assign them the Null or an empty value.  I just finished a programming gig where I had to build dynamically sized bars from the base data.  Kind of like creating 15, 30, 60-minute bars from a 5-minute bar chart or stream.   I did this using arrays because I wanted to be able to index into them to go back in time and I didn’t how far I wanted to go back.  So I declared some arrays with large dimensions to be safe.  This really takes a bite out of your resources which costs space and time.  I had played with Vector like objects in Python, so I thought I would post about them here and show how cool they are.  Remember this is a rudimentary program and could be streamlined and cleaned up.  Each vector will store their respective time, open, high, low and close values of the combined bar.  In a later post, I would like to do this with a Dictionary.  So the opVector will hold the open price, the hiVector will hold the high price and so on.

Build a Queue – why the extra ue?

I want to build 15-minute bars from 5-minute bars so I need to know when to sample the data to properly collect the corresponding data.  If I start at 9:30 then I want to sample the data at 9:45 and look back three bars to get the open and the highest high and the lowest low.  The close will simply be the close of the 9:45 bar.  I want to do this at 9:45, 10:00. 10:15 and so on.  I could manipulate the time and use the modulus function to see if the minutes are multiples of 15 and I tried this but it didn’t work too well.  So I thought since I was already in the collections why not build a list or a queue with all the timestamps I would need.  This is how I did it.

vars: hrs(0),mins(0),barMult(3),combBarTimeInterval(0),totBarsInHour(0),startTime(930),endTime(1615),cnt(0);

Once
Begin
	mins = fracPortion(t/100);
	combBarTimeInterval = barInterval*barMult;
	While value1 < endTime
	Begin
		cnt = cnt + 1;
		Value1 = calcTime(startTime,cnt*combBarTimeInterval);
//		print("Inside queue : ",Value1," ",cnt*combBarTimeInterval);
		timeStampQue.Enqueue(Value1);
	end;	
end;
Populating A Queue With Time Stamps

I simply use the CalcTime function to add 15-minute intervals to the start time and then I add them to the queue:  timeStampQue.Enqueue(Value1);  You access the methods or tools to a class by using the dot (” . “) notation.  Once I instantiated or created the timeStampQue I gained access to all the tools that belong to that object.  The Enqueue method simply appends the list the value that you pass it.  I would have preferred the method to be labeled simply add.  How did I figure out the right method name you ask?  I accessed the Dictionary from the View menu in the TDE.  Here is a picture to help:

Dictionary:

I use the keyword Once to just execute the code one time.  You could have said if BarNumber = 1, but why not use the tools at your disposal,   I figured out the combBarTimeInterval by using the 5-minute bar multiplier (3).  I then looped from startTime to endTime in 15-minute intervals and stored the timeStamps in the queue.  So every time stamp I need is in the timeStampQue.  All I need now is to compare the time of the 5-minute bar to the time stamps inside the queue.  This is where using object really come in handy.

Queue Methods:

Old school would have looped through all of the elements in the list and compared them to the value I was seeking and if found it would return true.  In the object world, I can simply ask the object itself to see if the value is in it:

condition1 = timeStampQue.Contains(t);

Cool!  If condition1 is true then I know I am sitting on the 5-minute bar that shares the same timestamp as a 15-minute bar.  If the time stamps are the same then I can start building the large timeframe from the lower timeframe.  You add elements to a vector by using the insert method.  I simply looked it up in the dictionary.   I had to specify where to insert the value in the vector.  I simply inserted each value into the [0] location.  Remember we are inserting so everything else in the vector is moved down.

Vector Methods:

 

If condition1 then
Begin
	barVector.insert(0,t);
	opVector.insert(0,open[2]);
	hiVector.insert(0,highest(h[0],3)); 
	loVector.insert(0,lowest(l[0],3));
	clVector.insert(0,close[0]);
end;
Inserting Values at Vector Location 0

I only need to keep track of the last 10 15-minute bars, so once the vector count exceeded 10, I simply popped off the value at the back end – pop_back().  I figured this out by looking at Martin Whittaker’s awesome website – www.markplex.com. 

 

If opVector.Count > 10 then 
begin
    barVector.pop_back();
	opVector.pop_back();
	hiVector.pop_back();
	loVector.pop_back(); 
	clVector.pop_back();
end;
Popping the Back-End

To check my work I printed the 15-minute bars on each 5-minute bar to make sure the bars were being built properly.  These data structures expect an object to be inserted, added, popped so when you print out one of their values you have to tell the print statement what the object should be translated as.  Here the keyword asType comes into play.  Take a look at my code, and you will see what I mean.  I hope this gets you excited about objects because the collections class can save you a ton of time and is really cool.  Use it and you can brag that you are an OOP programmer at your next cocktail party.

Code Listing:
Using elsystem.collections;

Vars: Vector opVector(NULL),
      Vector hiVector(Null),
      Vector loVector(Null),
      Vector clVector(Null),
      Vector barVector(Null),
      Queue timeStampQue(Null);
Once
Begin
	barVector = new Vector;
	opVector = new Vector;
	hiVector = new Vector;
	loVector = new Vector;
	clVector = new Vector;
	timeStampQue = new Queue;
end;

vars: hrs(0),mins(0),barMult(3),combBarTimeInterval(0),totBarsInHour(0),startTime(930),endTime(1615),cnt(0);

Once
Begin
	mins = fracPortion(t/100);
	combBarTimeInterval = barInterval*barMult;
	While value1 < endTime
	Begin
		cnt = cnt + 1;
		Value1 = calcTime(startTime,cnt*combBarTimeInterval);
//		print("Inside queue : ",Value1," ",cnt*combBarTimeInterval);
		timeStampQue.Enqueue(Value1);
	end;	
end;	
	
	
	
condition1 = timeStampQue.Contains(t);

Print(d," ",t," ",condition1);

If condition1 then
Begin
	barVector.insert(0,t);
	opVector.insert(0,open[2]);
	hiVector.insert(0,highest(h[0],3)); 
	loVector.insert(0,lowest(l[0],3));
	clVector.insert(0,close[0]);
end;
 
If opVector.Count > 10 then 
begin
    barVector.pop_back();
	opVector.pop_back();
	hiVector.pop_back();
	loVector.pop_back(); 
	clVector.pop_back();
end;

vars:vectCnt(0);
print(d," ",t);
If opVector.Count > 9 then
Begin
	For vectCnt = 0 to 9 
	begin
		print(vectCnt," ",barVector.at(vectCnt) astype int," ",opVector.at(vectCnt) astype double," ",hiVector.at(vectCnt) astype double," ",loVector.at(vectCnt) astype double," ",clVector.at(vectCnt) astype double);
	end;
end;
Program in its Entirety

 

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