McClellan Summation Index?

TS and MC both have the McClellan Oscillator, and with correct data inputs (typically the NYSE advancers and decliners), it works pretty good, as measured against the published numbers.

Is there a lot involved in creating the McClellan Summation Index, which is built upon the Oscillator? It is said to be (calculation):

Previous day's Summation Index* + current day McClellan Oscillator

* The very first Summation Index is simply the value of the McClellan Oscillator.


Thanks for any help you can provide.