Fixing RP Score 2011

In February 2011 we added achievements to Stendhal in order to encourage players to have a far richer playing experience than just killing monsters. This has really worked out great with - at the time of writing - over 12000 achievements granted. Feedback from players has been very positive and many players have discovered aspects of Stendhal that they did not pay attention to.

In March we improved the hall of fame to take the achievement score into account for the best player calculation. After some initial struggling because it caused some players to temporary drop out of the top 10, this did work fine, too. But here we introduced a bug. The ranking itself is fine, but the score is not.

What's wrong with the RP score?

The RP score graph has an exponential growth, just like the XP requirement per level.

Why is that bad?

• It means that weak players don't have a chance to get RP points.
• The average level of someone having an RP score above 0 is 150.
• One third of all players is below level 10, two thirds are below level 50.
• The numbers get really big at the upper end of the hall of fame
• Rounding errors in the ranking start at rank 150.

What is good?

The ranking itself (above the rounding error boundary where lots of people have the exact same score) is accurate

What is the bug?

The bug is that the calculation is missing a logarithm operation.

Wait, logarithms are really difficult, don't they totally screw up scale?

Actually, in most cases the logarithm is a very natural thing: It's often used by biologists to describe grows of plants and animals. Applying logarithm to XP points has a very long tradition in role playing games. Of course, calling it "level" instead of "logarithm of xp" makes it a lot less scary.