FastR experiments with Sudoku code extracted (Rcpp ignored)
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| sudokuTxt <- " | |
| 1 0 0 0 0 0 0 0 6 | |
| 0 0 6 0 2 0 7 0 0 | |
| 7 8 9 4 5 0 1 0 3 | |
| 0 0 0 8 0 7 0 0 4 | |
| 0 0 0 0 3 0 0 0 0 | |
| 0 9 0 0 0 4 2 0 1 | |
| 3 1 2 9 7 0 0 4 0 | |
| 0 4 0 0 1 2 0 7 8 | |
| 9 0 8 0 0 0 0 0 0" | |
| sudoku <- as.matrix( | |
| read.table(text = sudokuTxt, | |
| col.names = letters[1:9])) | |
| library(zeallot) | |
| library(magrittr) | |
| solve <- function(partialSolution, choicesFUN) { | |
| # Eliminate impossible values, give some suggestions | |
| # and flag contradictions. | |
| c(partialSolution, suggestions, contradiction) %<-% | |
| eliminate(partialSolution, choicesFUN) | |
| # If dead end FALSE to trace back, if finished TRUE. | |
| if (contradiction) return(list(FALSE, NULL)) | |
| if (all(partialSolution %in% 1:9)) | |
| return(list(TRUE, partialSolution)) | |
| # Branching, exit when the solution is found. | |
| for (suggestion in suggestions) { | |
| c(result, solution) %<-% solve(suggestion, | |
| choicesFUN) | |
| if (result) return(list(result, solution)) | |
| } | |
| list(FALSE, NULL) | |
| } | |
| eliminate <- function(grid, choicesFUN) { | |
| suggestions <- 0:9 | |
| for (i in 1:nrow(grid)) { for (j in 1:ncol(grid)) { | |
| if (grid[i, j] == 0L) { | |
| choices <- choicesFUN(grid, i, j) | |
| if (length(choices) == 0L) { | |
| return(list(NULL, NULL, TRUE)) | |
| } else if (length(choices) == 1L) { | |
| grid[i, j] <- choices | |
| return(list(grid, list(grid), FALSE)) | |
| } else | |
| suggestions <- updateSuggestions( | |
| choices, grid, i, j, suggestions) | |
| } | |
| }} | |
| list(grid, suggestions, FALSE) | |
| } | |
| # Find all the choices allowed by the rules. | |
| findChoices <- function(grid, i, j) { | |
| 1:9 %>% setdiff(grid[i, ]) %>% | |
| setdiff(grid[ , j]) %>% | |
| setdiff(grid[i - (i - 1) %% 3L + 0:2, | |
| j - (j - 1) %% 3L + 0:2]) | |
| } | |
| # Create a list of grids with suggested next moves. | |
| updateSuggestions <- function(choices, grid, i, j, | |
| lastBest) { | |
| if (length(choices) < length(lastBest)) | |
| lapply(choices, function(choice) { | |
| grid[i, j] <- choice; grid | |
| }) | |
| else | |
| lastBest | |
| } | |
| solution <- solve(sudoku, findChoices) | |
| if (!solution[[1]]) { cat('Solution not found\n') | |
| } else { print(as.data.frame(solution[[2]])) } | |
| sudokuTxt <- " | |
| 8 0 0 0 0 0 0 0 0 | |
| 0 0 3 6 0 0 0 0 0 | |
| 0 7 0 0 9 0 2 0 0 | |
| 0 5 0 0 0 7 0 0 0 | |
| 0 0 0 0 4 5 7 0 0 | |
| 0 0 0 1 0 0 0 3 0 | |
| 0 0 1 0 0 0 0 6 8 | |
| 0 0 8 5 0 0 0 1 0 | |
| 0 9 0 0 0 0 4 0 0" | |
| sudoku <- as.matrix( | |
| read.table(text = sudokuTxt, | |
| col.names = letters[1:9])) | |
| solve2 <- function(partialSolution, choicesFUN) { | |
| # Eliminate impossible values, give some suggestions | |
| # and flag contradictions. | |
| elStep <- eliminate(partialSolution, choicesFUN) | |
| # If dead end FALSE to trace back, if finished TRUE. | |
| if (elStep[[3]]) return(list(res = FALSE, | |
| sol = NULL)) | |
| if (all(elStep[[1]] %in% 1:9)) | |
| return(list(res = TRUE, sol = elStep[[1]])) | |
| # Branching, exit when the solution is found. | |
| for (suggestion in elStep[[2]]) { | |
| ans <- solve2(suggestion, choicesFUN) | |
| if (ans$res) return(ans) | |
| } | |
| list(res = FALSE, sol = NULL) | |
| } | |
| findChoices2 <- function(grid, i, j) { | |
| setdiff(setdiff(setdiff(1:9, | |
| grid[i, ]), | |
| grid[ , j]), | |
| grid[i - (i - 1) %% 3L + 0:2, | |
| j - (j - 1) %% 3L + 0:2]) | |
| } | |
| print(microbenchmark::microbenchmark( | |
| solve2(sudoku, findChoices2), | |
| control = list(warmup = 20L) | |
| )) |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| library(microbenchmark) | |
| sqr <- function(x) x * x | |
| f1 <- function() for (n in 1:1000) sqr(runif(1:n)) | |
| print(R.version) | |
| print(microbenchmark(f1(), control = list(warmup = 100L))) |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #include <Rcpp.h> | |
| using namespace Rcpp; | |
| IntegerMatrix subGrid(IntegerMatrix& x, int i, int j) { | |
| i -= i % 3; j -= j % 3; | |
| return x(Range(i, i + 2), Range(j, j + 2)); | |
| } | |
| // [[Rcpp::export]] | |
| IntegerVector findChoicesCpp(IntegerMatrix& x, | |
| int i, int j) { | |
| IntegerVector candidates(9); | |
| std::iota(candidates.begin(), candidates.end(), 1); | |
| // C++ is zero-indexed. | |
| return setdiff(setdiff(setdiff(candidates, | |
| IntegerVector(x(i - 1, _))), | |
| IntegerVector(x(_, j - 1))), | |
| subGrid(x, i - 1, j - 1)); | |
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| library(Rcpp) | |
| library(microbenchmark) | |
| sudokuTxt <- " | |
| 8 0 0 0 0 0 0 0 0 | |
| 0 0 3 6 0 0 0 0 0 | |
| 0 7 0 0 9 0 2 0 0 | |
| 0 5 0 0 0 7 0 0 0 | |
| 0 0 0 0 4 5 7 0 0 | |
| 0 0 0 1 0 0 0 3 0 | |
| 0 0 1 0 0 0 0 6 8 | |
| 0 0 8 5 0 0 0 1 0 | |
| 0 9 0 0 0 0 4 0 0" | |
| sudoku <- as.matrix( | |
| read.table(text = sudokuTxt, | |
| col.names = letters[1:9])) | |
| eliminate <- function(grid, choicesFUN) { | |
| suggestions <- 0:9 | |
| for (i in 1:nrow(grid)) { for (j in 1:ncol(grid)) { | |
| if (grid[i, j] == 0L) { | |
| choices <- choicesFUN(grid, i, j) | |
| if (length(choices) == 0L) { | |
| return(list(NULL, NULL, TRUE)) | |
| } else if (length(choices) == 1L) { | |
| grid[i, j] <- choices | |
| return(list(grid, list(grid), FALSE)) | |
| } else | |
| suggestions <- updateSuggestions( | |
| choices, grid, i, j, suggestions) | |
| } | |
| }} | |
| list(grid, suggestions, FALSE) | |
| } | |
| updateSuggestions <- function(choices, grid, i, j, | |
| lastBest) { | |
| if (length(choices) < length(lastBest)) | |
| lapply(choices, function(choice) { | |
| grid[i, j] <- choice; grid | |
| }) | |
| else | |
| lastBest | |
| } | |
| solve2 <- function(partialSolution, choicesFUN) { | |
| # Eliminate impossible values, give some suggestions | |
| # and flag contradictions. | |
| elStep <- eliminate(partialSolution, choicesFUN) | |
| # If dead end FALSE to trace back, if finished TRUE. | |
| if (elStep[[3]]) return(list(res = FALSE, | |
| sol = NULL)) | |
| if (all(elStep[[1]] %in% 1:9)) | |
| return(list(res = TRUE, sol = elStep[[1]])) | |
| # Branching, exit when the solution is found. | |
| for (suggestion in elStep[[2]]) { | |
| ans <- solve2(suggestion, choicesFUN) | |
| if (ans$res) return(ans) | |
| } | |
| list(res = FALSE, sol = NULL) | |
| } | |
| Rcpp::sourceCpp('sudoku.cpp') | |
| solve2(sudoku, findChoicesCpp) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment