View source for Details about the comparison between SM-17 and SM-2

== Question ==

In [[Algorithm SM-17 vs. older SuperMemos]], the [[retrievability]] prediction in SM-2 can be obtained from:

  SM2R:=Exp(-MDC*Int/SM2Int)

But the page didn't provide the value of MDC. Can I use SM2Int as [[stability]]? In this case, MDC = -ln(0.9) = 0.1053605157.

I'm building benchmark for [[spaced repetition]] algorithm, here is the link of our repo: https://github.com/open-spaced-repetition/fsrs-benchmark

SM-2 is a popular and famous spaced repetition algorithm, so I want to add it into our baseline.

== Answer ==

In [[SuperMemo 18]] code you have this:
  MDC:real; //memory decay constant
  MDC:=ln(10/9);

The original algorithm is described [https://supermemo.guru/wiki/SuperMemo_1.0_for_DOS_(1987)#Algorithm_SM-2 here]. The term [[stability]] was not used then, but [[interval]] reflects the concept of [[stability]].

(thank you for working on this, independent code will be helpful to verify claims of SuperMemo)