I need to back test some strategies. The strategies would need to first scan the market for entry conditions and apply the entry, stop and exit scenarios to all the scan results for each of the days in the testing period. Can you please suggest the right tool that I should focus and learn to give me maximum effectiveness in testing this. I do not want to test a strategy on one single instrument but to whole market or at least a basket of stocks e.g. NDX 100. Tradestation would handle single instrument testing, but I am looking for a scan first. Any suggestions would be greatly appreciated. Thanks, Rahul