Add analysis of review logs in the optimizer of FSRS

[L.M.Sherlock]

@kuroahna

What does the first column represent? Such as the number 152 in

It is the index auto-generated by Pandas. You can ignore it.

@kuroahna

And for r_history, you mention that it is “the history of ratings on each review”, so does 3,3,3,1 means that you press Good, Good, Good, then Again?

Yes, but it doesn’t contain those reviews in learning steps shorter than 1 day.

@kuroahna

“avg_ivl is the average interval when you reviewed cards”. Is this the average interval for the cards you reviewed that day? Or is it the average interval for the cards that you cumulatively reviewed up to that day?

It is the average interval for the cards that you cumulatively reviewed up to that day.

@kuroahna

“When the required retention is 90%, the avg_ivl is too short when the avg_retention is bigger than `90%” I don’t think I fully understand this, can you rephrase it? Perhaps with some examples?

The average interval is coming from Anki SM2 and the delay that you actual reviews.

The average retention is coming from your reviews at those intervals.

Anki’s manual said that:

For moderately difficult material, the average user should find they remember approximately 90% of mature cards that come up for review.

So if your retention is less than 90%, it means that the default interval is too long for you. If it is bigger than 90%, the interval is too short.