Some of our mechanical systems have a function called "hijack" - which allows you to take discretion when you want to. The "system" gets you into a trade, and you have the choice to let it get you out, or to "hijack" the trade and get out yourself.
My take...
Both styles look for patterns.
Discretionary trading...
- can not handle a large number of transactions at the same time
- has to win emotions
- risk of human error
- slower execution
+ can deal with unexpected conditions and new variables immediately
+ adapts faster
+ doesn't need to be programmed (no risk of programming error, no development time and related costs)
