Improvement of the difficulty predictor

[Nytilde]

Why clipping is not as bad as it looks, and how we can use the features to make recommendations for better map-design.

How the current predictor works

These features are used in the new difficulty predictor: ["AverageTimeDifference", "d1min", "HighNoteDensity2s", "NoteDensity", "cdw"]

To analyze the behavior of a regular map, one must initially ascertain its rate of change. This is accomplished by differentiating a time function with respect to time. However, in practical applications, we utilize a time vector to compute time differences, enabling the determination of the iterator's change with a lag of one:

Figure 1: Rate of Change

The presence of high peaks in the data indicates longer breaks, while the lower sections indicate a higher density of notes in the area. Ultimately, we use the average rate of change, which heuristically provides the best general separation performance according to the Exploratory Data Analysis (EDA). This separation performance in the level 1 range could be further improved with the 40% quantile.

HighNoteDensity2s corresponds approximately to the rolling density and has a high classification performance in the upper level range but decreases in the lower level range.

Figure 2: HighNoteDensity2s

NoteDensity offers a generally uniform but not so pronounced differentiation of all level ranges.

Figure 3: NoteDensity

cdw follows the approach of counting all notes in a constant window range in the higher velocity range. This feature contributes only minimally to the improvement but could slightly raise the classification in the middle range.

Figure 4: cdw

The next step is to introduce the influence of the pattern (work in progress).

My Considerations

What do models that are filtered via clipping tell us? In principle, we need to look in detail at which features do not match, and we can determine from the resulting deviations.

According to my observations, most outliers in the lower and middle levels often indicate little variety in the beatmap. Recommendation: include more breaks to make it more varied.

I am always open to further suggestions and constructive criticism of my ideas.