Let discuss in this topic the benefits of replacement of the currently used Sudoku Explainer with SKFR.

Currently a special build of Sudoku Explainer 1.2.1 by Nicolas Juillerat is in use. The link to the special build and details on its functionalities are explained in the opening post of the Patterns Game topic.

SKFR is alternative rating program written by Gerard Penet. Its source in C++ is available at http://code.google.com/p/skfr-sudoku-fast-rating/ and there is open discussion in this forum at http://forum.enjoysudoku.com/cloning-sudoku-explainer-thru-tagging-t30132.html.

Known facts:

- Sudoku Explainer is de facto standard in Sudoku Puzzle Rating.
- Sudoku Explainer is written in Java.
- Sudoku Explainer source is available.
- Sudoku Explainer has known bugs.
- Sudoku Explainer can rate any known puzzle.
- Sudoku Explainer's clone has conditional rating abilities.
- Sudoku Explainer is very slow for hardest puzzles.
- The author of Sudoku Explainer is inactive from years.
- There are clones of SE implemented by some authors in their code. Some of them have source code available for public use.
- There is database with puzzles played in past games which directly affect players score (rarity).
- Out of the scope of Patterns Game, a huge number of rated puzzles exists and they are spread in many personal collections.
- SKFR in general follows the rating rules of Sudoku Explainer.
- SKFR in written in C++ but not ANSI C++.
- SKFR source is available.
- SKFR has its known bugs which don't intentionally follow the Sudoku Explainer's bugs.
- SKFR has conditional rating abilities.
- SKFR is at least 100 times faster than Sudoku Explainer.
- SKFR is currently not 100% ready to replace SE and that is confirmed by its author.

Any comment from players, former and future players, and non-players is welcome.