Add Relative Vigor Index

[jealous]

The Relative Vigor Index (RVI) is a momentum indicator
used in technical analysis that measures the strength
of a trend by comparing a security's closing price to
its trading range while smoothing the results using a
simple moving average (SMA).

https://www.investopedia.com/terms/r/relative_vigor_index.asp

Formular

• NUMERATOR= (a+(2×b)+(2×c)+d) / 6
• DENOMINATOR= (e+(2×f)+(2×g)+h) / 6
• RVI= SMA-N of DENOMINATOR / SMA-N of NUMERATOR
• Signal Line = (RVI+(2×i)+(2×j)+k) / 6

where:

• a=Close−Open
• b=Close−Open One Bar Prior to a
• c=Close−Open One Bar Prior to b
• d=Close−Open One Bar Prior to c
• e=High−Low of Bar a
• f=High−Low of Bar b
• g=High−Low of Bar c
• h=High−Low of Bar d
• i=RVI Value One Bar Prior
• j=RVI Value One Bar Prior to i
• k=RVI Value One Bar Prior to j
• N=Minutes/Hours/Days/Weeks/Months

Examples:

• df['rvgi'] retrieves the RVGI line of window 14
• df['rvgis'] retrieves the RVGI signal line of window 14
• df['rvgi_5'] retrieves the RVGI line of window 5
• df['rvgis_5'] retrieves the RVGI signal line of window 5