Finding major peaks and troughs
 

Hi Guys, I wonder if anyone can share me on how to find the major peaks
and valleys(trough) of an array of time series daily data (eg. stock
data).
A major Peak needs the following conditions to be formed:
1. Must be the highest peak since last major Trough and
2. Must be at least some percentage (eg. 10%) higher than that Trough.

A major Trough needs the following:
1. Must be the lowest trough since last major Peak and
2. Must be at least some percentage (eg. 10%) lower than that Peak.

You kind cooperation is very much appreciated.


zack