iPad App Sudoku Fundamentals Improvements

Programs which generate, solve, and analyze Sudoku puzzles

iPad App Sudoku Fundamentals Improvements

Postby nedBlake » Mon Jun 05, 2017 6:11 pm

The description of Sudoku Fundamentals in the App store gives you a full description of this App along with screenshots, of which the following is a summary:

This App is currently free (and probably will continue to be).

It has four levels of puzzle libraries from "Easy" to "Extreme", corresponding to the four levels of strategies described in the Fundamentals.

There are also four levels of visual aids that you can use to solve these puzzles. The important ones are: the ability to autofill all empty cells with possible solutions at the "Moderate" level, plus the abilty to highlight all instances of a possible at the "Hard" level, plus the ability to draw implication chains with your finger at the "Extreme" level.

You can Import puzzles. In particular, you can bring this site up on your iPad and copy the text image of a puzzle you see in this site's Puzzles forum, and then use the Import action of this App. Import ignores everything, including white space, except numbers and the period used to indicate empty cells.

Import uses a solver to check that the puzzle is solvable, and then grades the puzzle. As shown in the "Create" example below, the Grader can display an abbreviated summary of what strategies were used by the Grader to solve the puzzle.

You can Create puzzles. A significantly improved Grader is now used during this process. The last topic in the "Fundamentals" describes how puzzles are created using a combination of random and manual input, how clues are distributed, and how patterns are created.

Release 2.2

The following image is part of a screenshot of the Create action in release 2.2 that was just released. This image shows the menu displayed after the Random action is selected:

rel 22 Random menu.png
rel 22 Random menu.png (17.47 KiB) Viewed 52 times

This ability to create a puzzle at a selected level is new with this release, and is possible due to major improvements of the Grader, which has made steps towards measuring quality as well as difficulty. For each strategy level, you can select 3 levels of difficulty, and 4 for the Extreme level - the 4th level means that the Grader wasn't able to solve the puzzle, most likely because a strategy is needed that is not yet described in the Fundamentals.

Suppose that you select Moderate ** as the puzzle you want to create. Random will then create 100 puzzles, trimming unnecessary clues to create a group of puzzles at this puzzle level. Statistics generated by the Grader for each of these puzzles are compared, and the "best" puzzle is selected. This may take 5 or 10 seconds.

rel 22 Created puzzle.png
rel 22 Created puzzle.png (24.28 KiB) Viewed 40 times

The puzzle is displayed with the comment that it was the best of a group of 15. This was based on Grader statistics that indicated more successful strategies were used solving this puzzle compared to others in the group, and also the "given" naked singles (iNS + fNS: the initial plus the final succession of naked singles) was reasonably low, implying that naked singles were distributed more throughout the puzzle solution, and are more the result of strategy applications instead of just the result of other singles being solved.
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