What are the calculations to create a "currency strength" indicator or EA?

 
Is there an existing article or code or even an open code pinescript in which we can understand the mathematics and logics behind the concept and practical use of the so-called "currency strength" in a way possible to reproduce it in EA's or indicators?
 

It is called the search function on this site:

Searching the CodeBase with keywords "currency strength": https://www.mql5.com/en/search#!keyword=currency%20strength&module=mql5_module_codebase

 
Fernando Carreiro #:

It is called the search function on this site:

Searching the CodeBase with keywords "currency strength": https://www.mql5.com/en/search#!keyword=currency%20strength&module=mql5_module_codebase

Thanks for the tip!! Have a great day.