AmiBroker Formula Language Tools

AFL Tools

Automatic technical analysis

Introduction

Since version 2.5, AmiBroker features automatic technical analysis tools. AmiBroker can check for user-defined buy/sell conditions, giving you an idea about the current situation on the market. It can also perform a system test (simulation), telling you about the performance of your trading system. Version 3.0 of AmiBroker introduced a new formula language (AFL), allowing you to write not only system tests but also custom indicators and guru advisor commentaries.

In order to do this, you have to define buy and sell rules, indicator formulas, or commentaries using a special AmiBroker Formula Language (AFL), which is described below. For more information about using analysis tools, see also the description of the Automatic Analysis window, Formula Editor, and Commentary window in Chapter 2.

AmiBroker Formula Language

AFL is used for defining your trading rules and explorations in the Automatic Analysis window, custom commentaries in the Guru Commentary window, and indicator formulas in the Formula Editor window.

A detailed reference of the AFL language is given here.

Examples

Below you will find some simple buy and sell rules. They are just formal equivalents of some of the most common indicators' interpretation rules. You can treat them as a starting point for developing your own trading strategies, but before you get too excited when you think you've found the "holy grail" of trading systems, check the following:

Test the system on different symbols and different timeframes. The results should be similar to those of the original data tested.
Test the system on different types of markets (e.g., upward trending, downward trending, and sideways). A good system should work in all types of markets, since you won't always know when a market changes from trending to trading or vice versa.
Pay close attention to the number of trades generated by a trading simulation. If there are a large number of trades and large profits, be sure you specified realistic commissions. The results of the test may be much different once commissions are factored in.

buy = cross( macd(), 0 ); sell = cross( 0, macd() );

buy = cross( ema( close, 9 ), ema( close, 15 ) ); sell = cross( ema( close, 15 ), ema( close, 9 ) );

buy = cross( rsi(), 30 ); sell = cross( 70, rsi() );

buy = cross( ultimate(), 50 ); sell = cross( 50, ultimate() );

Automatic Analysis window

The Automatic Analysis window enables you to check your quotations against defined buy/sell rules. AmiBroker can produce a report telling you whether buy/sell signals occurred on a given symbol in the specified period. It can also simulate trading, giving you an idea about the performance of your system.

In the upper part of the window, you can see a text entry field. In this field, you should enter buy and sell rules. These rules are assignment statements written in AmiBroker's own language. You can find the description of this language in the AFL reference guide.

In order to make things work, you should write two assignment statements (one for a buy rule, the second for the sell rule), for example:

buy = cross( macd(), 0 ); sell = cross( 0, macd() );

The Automatic Analysis window also allows you to optimize your trading system and perform in-depth explorations.

Formula Editor

The Formula Editor allows you to write formulas to be used as indicators or in the Automatic Analysis window. More on this
here.

Guru Advisor Commentary window

The Commentary window enables you to view textual descriptions of the actual technical situation on a given market.
Commentaries are generated using formulas written in AmiBroker's own formula language. You can find the description of this language in AmiBroker Formula Language Reference Guide.

Moreover, the Commentary feature also gives you a graphical representation of buy & sell signals by placing the marks (arrows) on the price chart.

NOTE: Using complex commentary formulas, you may observe long execution times.