sc330_f2016:prolog2
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sc330_f2016:prolog2 [2017/03/14 18:29] dhart [Hints] |
sc330_f2016:prolog2 [2018/02/26 18:25] morse |
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| ====Hints==== | ====Hints==== | ||
| - | *Whenever an integer is inserted into a blank space recheck the Sudoku constraints. The idea is to fail as quickly as possible to avoid extra work. The ''is_set/1'' in the lists library '':- use_module(library(lists)).'' predicate should be useful. | + | * Whenever an integer is inserted into a blank space recheck the Sudoku constraints. The idea is to fail as quickly as possible to avoid extra work. The ''is_set/1'' in the lists library '':- use_module(library(lists)).'' predicate should be useful. |
| - | *Instantiate blank squares form left to right, top to bottom. While not vital, our test problems were chosen to run faster for algorithms that choose that order. | + | * Instantiate blank squares form left to right, top to bottom. While not vital, our test problems were chosen to run faster for algorithms that choose that order. |
| - | * <code prolog>(nonvar(S00); var(S00), digit(S00), is_set(Row0), is_set(Col0), is_set(Cub0)) </code>, will check if a single square is correct. Do this for each spot, use lists and helpers to traverse through the board. **Edit Nov 1 ** Where S00, is the spot at 0, 0, Row0, Col0, and Cub0 are the first row, col, and cube respectively. You shouldn't explicitly make variables for each of them, but access each space recursively. | + | * The code <code prolog>(nonvar(S00); var(S00), digit(S00), is_set(Row0), is_set(Col0), is_set(Cub0)) </code> will check if a single square is correct, where S00 is the spot at (0,0) and Row0, Col0, and Cub0 are the first row, col, and cube respectively. You shouldn't explicitly make variables for each of them, but access each space recursively. Do this for each spot, and use lists and helpers to traverse through the board. |
| ===Tips to Make Faster (if needed)=== | ===Tips to Make Faster (if needed)=== | ||
| - | If your code takes longer than a minute to run,consider the following ideas: | + | If your code takes longer than a minute to run, consider the following ideas: |
| *Preprocess the board so all columns and 3x3 sub-grids are immediately available as data in some structure(s). The ''getCube/3'' and ''columnAsList/3'' helper functions are expensive and should not be repeated often. | *Preprocess the board so all columns and 3x3 sub-grids are immediately available as data in some structure(s). The ''getCube/3'' and ''columnAsList/3'' helper functions are expensive and should not be repeated often. | ||
| *Only check constraints relative to changes made. | *Only check constraints relative to changes made. | ||
sc330_f2016/prolog2.txt · Last modified: 2021/06/30 23:42 (external edit)
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