I was wondering the same thing. I normally just eyeball the the Day chart to determine the direction of the trend or if the market is rangebound.

However a way I imagine if you take a set number candles on the day chart say 21 candles and if a certain percentage of those candles had higher highs and/or higher lows then that would qualify for an uptrend. A down trend will of course be the reverse of the above.

A ranging market would be somewhere between the uptrend and downtrend.

I am sorry I have not totally figured out a way to determine trending/ranging market mathematically, I was hoping to get some ideas from the forum in order to put this Expert Advisor together.

By the way although I use the Day Chart to determine the trend I would actually have the trades execute on the 15 minute chart.

Hope that makes sense.