Grucha Percentage Index originally created by Polish coder named Grzegorz Antosiewicz in 2011 as mql code. This code is adapted by his original code to tradingview's pinescript.
What Does it Do
GPI is an oscillator that finds the lowest/highest prices with certain depth and generates signals by comparing the bull and bear bars. It use two lines, one is the original GPI calculation, the other is the smoothed version of the original line.
How to Use
GPI can catch quick volatility based movements and can be used as a confirmation indicator along with your existing trading system. When GDI (default color yellow) crosses above the GDI MA (default colored blue) it can be considered as a bullish movement and reverse can be considered as bearish movement.
How does it Work
The main calculation is done via the code below:
for i=0 to length
if candleC < 0
minus += candleC
if candleC >= 0
plus -= candleC
Simply we are adding green and red bars seperately and then getting their percentage to the bullish movement to reflect correctly in a 0-100 z-score enviroment via the code below:
res = (math.abs(minus)/sum)*100
Rest is all about plotting the results and adding seperate line with smoothing.
Note
These kind of oscillators are not designed to be used alone for signal generation but rather should be used in combination with different indicators to increase reliability of your signals.
Happy Trading.
Can I suggest just several useful additions:
1) It Would be great to have MTF option
2) It is very useful to have several level lines on the indicator like 20,50 and 70 for example
3) Also, it would be great to have ability to chose type of the MA (e.g. EMA, SMA, Hull, etc.)