http://www.amibroker.com/kb Providing you with tips & tricks for everyday AmiBroker use Thu, 23 Apr 2009 09:02:07 +0000 http://backend.userland.com/rss092 en IMPORTANT: This article applies ONLY to AmiBroker version 5.24 and earlier. Version 5.25 includes native support for log scale in Study() function and this workaround is no longer needed. Some of you may have tried using Study() function in logarithmic scale charts and noticed that the output of Study() function becomes ... http://www.amibroker.com/kb/2009/04/22/study-function-in-logarithmic-scale/ Sometimes when using low-level graphics functions it is needed to convert from bar number to pixel X co-ordinate and from price level to pixel Y co-ordinate. Converting between them needs knowing visible bar range, Y-axis value range and pixel dimensions of drawing area. Once these params are known it is ... http://www.amibroker.com/kb/2009/03/30/how-to-convert-from-bar-value-to-pixel-co-ordinates/ AmiBroker Formula Language (AFL) thanks to its array processing model is able to run at the same speed as code written in assembler (i.e. machine code). The following article explains how. AFL runs with native assembly speed when using array operations. A simple array multiplication like this: X = Close ... http://www.amibroker.com/kb/2008/08/12/afl-execution-speed/ That is the common question we receive through support channel, so even though it is explained in the LICENSE.TXT file that you have in your AmiBroker folder, let us make some facts straight. First take a look what the license says: "REGISTERED VERSION: One registered copy of the program may either be used ... http://www.amibroker.com/kb/2008/07/05/single-license-use-on-multiple-computers/ QuickAFL(tm) is a feature that allows faster AFL calculation under certain conditions. Initially (since 2003) it was available for indicators only, as of version 5.14+ it is available in Automatic Analysis too. Initially the idea was to allow faster chart redraws through calculating AFL formula only for that part which is ... http://www.amibroker.com/kb/2008/07/03/quickafl/ Recently on the AmiBroker mailing list some users expressed wish to have access to some of portfolio backtest metrics available in "historical" form (i.e. as date series, as opposed to scalars), so they can be plotted as an indicator. Implementing such functionality is actually easy with existing tools and does not ... http://www.amibroker.com/kb/2008/05/19/historical-portfolio-backtest-metrics/ Recently I heard the suggestion to add a security symbol written in big letters in the chart background. Well, actually it is pretty simple to do using low-level gfx. Just add this code sniplet anywhere in your chart formula. GfxSetOverlayMode(1); GfxSelectFont("Tahoma", Status("pxheight")/2 ); GfxSetTextAlign( 6 );// center alignment GfxSetTextColor( ColorRGB( 200, 200, 200 ) ... http://www.amibroker.com/kb/2008/04/21/big-symbol-text-in-the-background/ Recently released AmiBroker 5.05 BETA features the automatic Walk-Forward Optimization mode. The automatic Walk forward optimization is a system design and validation technique in which you optimize the parameter values on a past segment of market data ("in-sample"), then test the system forward in time on data following the optimization segment ... http://www.amibroker.com/kb/2008/02/12/getting-started-with-automatic-walk-forward-optimization/ The code below is an little bit more complex example of Low Level Graphics functions (see http://www.amibroker.com/guide/a_lowlevelgfx.html) It allows to display three kinds of charts: yearly/monthly profit table yearly profit bar chart average monthly profit bar chart The type of chart is switchable from Parameters dialog. It should be applied to ~~~EQUITY - portfolio equity symbol ... http://www.amibroker.com/kb/2007/10/11/low-level-gfx-example-yearlymonthly-profit-chart/ There are a couple of things you need to know about Yahoo Finance pages that AmiQuote uses to download "historical" and "current" quotes. Current quotes are quotes for current day (or previous day if there is no trading session today). For example MSFT current quote page is here: http://finance.yahoo.com/q?s=MSFT AmiQuote uses rather "download ... http://www.amibroker.com/kb/2007/08/04/amiquote-and-free-data-from-yahoo/