A popup menu appears by right-clicking. Options are:
The keyboard shortcuts used are the following:
- New. Allows the user to select from 15 predefined puzzles of
increasing difficulty and in standalone (DOS) mode to Open
a saved game or to Save the current game (i.e., the sudoku
puzzle and the moves done so far).
- Edit. Opens up a sudoku editor. It allows the user to redefine
cells in the grid. Use the Clear button to clear all cells or
press '0', SPACE, DELETE or BACKSPACE to clear a single cell. All other
non-digit values are discarded. Move around with the arrows or
just click in a cell to edit. Use the editor to import puzzles
from popular generators or from books, journals etc. or to define and test
your own puzzle.
- Solve. Allows the user to Step through the solution
manually (one, five or ten steps at a time)
or launch automatic Run of the solution. It also
allows to Check the current state of the solution or to
Show all the solutions, in case more than one are found.
- Manual play. Allows the user to play manually the puzzle. Click in a
puzzle cell or move around with the arrows from cell to cell. When in a cell,
either type the possible numbers for the cell or click on the corresponding positions
on the right-hand 3x3 area. Typing an existing number or clicking on an existing number
removes this number from the possibilities for the selected cell. Control-click on
the right-hand 3x3 area to clear all the numbers for this cell. If you wish, you can
choose one number to highlight in single-numbered cells within the puzzle. Before moving
in a different cell, you can type a comment in the text area below the puzzle. This will
be automatically saved when you save the puzzle and can be retrieved during play-back
(however, retrieval is not allowed for regular users).
- Reset. Allows the user to restart the puzzle.
- Shift-"+", shift-control-"+",
shift-alt-"+": Step through the solution one, five or
ten steps at a time, correspondingly.
- Shift-"arrow", shift-control-"arrow",
shift-alt-"arrow": Step through a recorded game one, five
or ten steps at a time, correspondingly. The "arrow" can be any one of the four
keyboard arrow keys (up, down, left or right). This feature is available only in standalone
- Caution! While the automatic solution uses "batch" steps that span the whole
puzzle for several patterns, the play-back of a recorded game steps one cell at a time.
Thus many changes in internal cell possibilities will not be directly visible, unless
a manual player is invoked, which shows all the cell possibilities. This feature serves to
discourage cheating by the user: if a cell is manually edited in the player then the
play-back cannot proceed anymore.
- Alt-'o', alt-'s': Open a saved game or save the current one.
Loaded games can be stepped through and continued manually or automatically.
- This is a cognitive modeling study. It uses only four solving rules of
increasing complexity that recognize simple situations or patterns of numbers. For
arbitrary Sudoku-like puzzles that have multiple solutions or none, an additional
trial-and-error rule is used that allows to select options and backtrack, if necessary.
For a well-formed Sudoku that has a unique solution, there is no need to use
trial-and-error of any kind. In the case of multiple solutions, the solver will produce
the first three solutions reached (they can be inspected with the option "Show solutions"
from the popup menu). Finally, in the case of impossible puzzles the solver will report
there is no solution after a while of backtracking. More details will appear after
a trial period is over.
- Creating the puzzle is more complicated than solving it. Even when a puzzle is
correctly created, the rating of its difficulty may be largely arbitrary. From a
cognitive point of view, the solver gives its rating for the puzzle in terms of
the rules it used to solve it ("1-4" for regular Sudoku's with a single
solution, "abnormal" or "erroneous" for multiple or no
solution cases). More details will appear after the trial period is over.
Page last updated 8 January 2007.
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