Known Bugs and Limitations

7.1. Limited Puzzle Statistics

GNOME Sudoku ranks puzzles based on the number of squares that can be rapidly filled. The puzzle statistics box shows you the overall rating and shows you three pieces of information:

  • The number of squares fillable by elimination, starting from the blank grid (i.e. only a 2 can go in this box, so it must be a 2).
  • The number of squares fillable by filling, starting from the blank grid (i.e. only only one square in this row can be a 2, so it must be a 2).
  • The number of times in solving the puzzle that the computer had to use trial-and-error, or “guessing”, to solve the puzzle.

Many users are upset to know that the computer solver uses trial-and-error, especially since some Sudoku gurus say you should never guess to solve a puzzle. There are a number of other algorithms that can be implemented to help the computer solve sudoku, such as the swordfish and X-wings patterns.

At present, Sudoku only uses the two algorithms described above as well as trial-and-error. When the statistics box says that Sudoku needed to use trial-and-error X number of times, it does not mean that a human would have to use trial-and-error to solve the puzzle.