Ultimate Algorithmic Trading System

code. This is a very difficult thing to do if you are used to working in a bar-by-bar
paradigm. Instead, use something like this:
myValue = (H + L)/2;
Buy = C > myValue;
Tomasz Janeczko has provided this type of array processing functionality in his
software. This accomplishes the same thing as the previous if statement. How do
you think you compare today’s close with the prior day’s close? You can’t use an if
statement, so could you do it like this?
cond1 = C > C[1];
cond2 = C < C[1];
Buy= cond1;
Short = cond2;
If you type this in and check the syntax, it will pass. You will also be able to send it
to an Analysis window, and backtest it. However, it will not work. The computer
doesn’t come out and say, ‘‘I’m sorry, Dave, I’m afraid I can’t do that.’’ It just
won’t generate the correct trades. These statements are syntactically correct, but
they are logically incorrect. You are comparing the first element of the close array
with the close array. In other words, you are comparing an element in the list with
the list. This is how you do it in AFL:
cond1 = C > Ref(C,-1);
cond2 = C < Ref(C,-1);
Buy= cond1;
Short = cond2;
The Ref(C,-1) function returns the prior close price in the close array. The function
processes the array and allows you to compare today’s closing price with yesterday’s
closing price. You can use any negative number to reference previous values of any
array. You can do this as well:
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INTRODUCTION TO AMIBROKER’S AFL
myValue = (H + L)/2;
cond1 = myValue > Ref(myValue,-1);
And you have probably noticed that all lines end with a semicolon (;). This tells the
parser that the line of code has terminated and to go onto the next line. What do
you think the next bit of code does?
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