Add support for generating multiple puzzles

src/bin/generator.rs

@@ -4,22 +4,12 @@ use std::error::Error;
 use std::io::Write;
 use std::process::exit;
 use std::str::FromStr;
-use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::atomic::{AtomicI64, Ordering};
 use std::sync::{mpsc, Arc};
 use std::thread;
 use sudoku_solver::grid::{CellValue, Grid};
 use sudoku_solver::solver::{SolveController, SolveStatistics};
 
-/*
-We have to be very careful here because Grid contains lots of Rcs and RefCells which could enable mutability
-across multiple threads (with Rcs specifically even just counting the number of active references to the object
-involves mutability of the Rc itself). In my specific case with the generator here I know that all those Rcs
-and RefCells are fully encapsulated in the one Grid object I'm Sending and will never be accessed again from the thread
-that sent them after it's been Sent, so it's safe in this narrowly specific context.
-*/
-struct SafeGridWrapper(Grid);
-unsafe impl Send for SafeGridWrapper {}
-
 #[derive(Clone, Copy)] // Needed for argparse
 enum Difficulty {
     Challenge,
@@ -102,9 +92,10 @@ impl FromStr for Difficulty {
 fn main() {
     let mut debug = false;
     let mut max_hints = 81;
-    let mut max_attempts = 100;
+    let mut max_attempts: Option<usize> = None;
-    let mut filename: Option<String> = None;
+    let mut filename= String::new();
-    let mut difficulty = Difficulty::Challenge;
+    let mut number_puzzles: usize = 1;
+    let mut difficulty = Difficulty::Hard;
     let mut threads = 1;
     let mut print_possibilities = false;
 
@@ -122,12 +113,19 @@ fn main() {
         );
 
         ap.refer(&mut max_attempts)
-            .add_option(&["--attempts"], argparse::Store, "Number of puzzles each thread will generate to find an appropriate puzzle; default is 100");
+            .add_option(&["--attempts"], argparse::StoreOption,
+                        "Number of puzzles attempted to find the appropriate puzzles; default is 100*(num-puzzles)");
 
         ap.refer(&mut filename).add_argument(
             "filename",
-            argparse::StoreOption,
+            argparse::Store,
-            "Optional filename to store puzzle in as a CSV",
+            "Filename to store puzzle(s) in as a CSV or pdf",
+        ).required();
+
+        ap.refer(&mut number_puzzles).add_option(
+            &["--num-puzzles"],
+            argparse::Store,
+            "Number of puzzles to generate; default 1"
         );
 
         ap.refer(&mut difficulty).add_option(
@@ -151,9 +149,11 @@ fn main() {
         ap.parse_args_or_exit();
     }
 
+    let max_attempts = max_attempts.unwrap_or(100 * number_puzzles);
+
     let solve_controller = difficulty.map_to_solve_controller();
 
-    let (result, num_attempts) = match threads.cmp(&1) {
+    let mut generated_grids_vec = match threads.cmp(&1) {
         ComparableOrdering::Less => {
             eprintln!("--threads must be at least 1");
             exit(1);
@@ -164,14 +164,16 @@ fn main() {
                 &mut rng,
                 &difficulty,
                 &solve_controller,
-                max_attempts,
                 max_hints,
-                &AtomicBool::new(false),
+                &AtomicI64::new(number_puzzles as i64),
+                &AtomicI64::new(max_attempts as i64),
                 debug,
             )
         }
+
         ComparableOrdering::Greater => run_multi_threaded(
             max_attempts,
+            number_puzzles,
             max_hints,
             threads,
             debug,
@@ -180,160 +182,154 @@ fn main() {
         ),
     };
 
-    let (grid, solve_statistics, num_hints) = match result {
-        Some(x) => x,
-        None => {
-            println!("Unable to find a desired puzzle in {} tries.", num_attempts);
-            return;
-        }
-    };
 
-    println!("{}", grid);
-    println!(
-        "Puzzle has {} hints and was found in {} attempts.",
-        num_hints, num_attempts
-    );
 
-    if debug {
+    if generated_grids_vec.len() < number_puzzles {
-        println!("Solving this puzzle involves roughly:");
+        println!("Unable to find {} puzzles in {} tries; instead {} puzzles were found.", number_puzzles, max_attempts, generated_grids_vec.len());
-        println!("\t{} SINGLE actions", solve_statistics.singles);
+        return
-        println!(
-            "\t{} HIDDEN_SINGLE actions",
-            solve_statistics.hidden_singles
-        );
-        println!(
-            "\t{} USEFUL_CONSTRAINT actions",
-            solve_statistics.useful_constraints
-        );
-        println!(
-            "\t{} POSSIBILITY_GROUP actions",
-            solve_statistics.possibility_groups
-        );
-        println!("\t{} GUESS actions", solve_statistics.guesses);
     }
 
-    if let Some(filename) = filename {
+    let mut grids_vec: Vec<Grid> = Vec::new();
+    for _ in 0..number_puzzles {
+        // It may happen that we generated more puzzles than we needed  - that's okay, we'll just ignore those
+        grids_vec.push(generated_grids_vec.pop().unwrap().grid);
+    }
+
+
     // check if we save to a csv or a pdf
     if filename.ends_with(".pdf") {
-            sudoku_solver::pdf::draw_grid(&grid, &filename, print_possibilities).unwrap();
+        sudoku_solver::pdf::draw_grids(&grids_vec, &filename, print_possibilities).unwrap();
         println!("Grid saved as pdf to {}", filename);
     } else {
-            save_grid_csv(&grid, &filename).unwrap();
+        save_grids_csv(&grids_vec, &filename).unwrap();
         println!("Grid saved as CSV to {}", filename);
     }
-    }
+
 }
 
+struct GeneratedGrid {
+    grid: Grid,
+    statistics: SolveStatistics,
+    num_hints: u64
+}
+
+/*
+We have to be very careful here because Grid contains lots of Rcs and RefCells which could enable mutability
+across multiple threads (with Rcs specifically even just counting the number of active references to the object
+involves mutability of the Rc itself). In my specific case with the generator here I know that all those Rcs
+and RefCells are fully encapsulated in the one Grid object I'm Sending and will never be accessed again from the thread
+that sent them after it's been Sent, so it's safe in this narrowly specific context.
+*/
+unsafe impl Send for GeneratedGrid {}
+
 fn run_multi_threaded(
-    max_attempts: i32,
+    max_attempts: usize,
-    max_hints: i32,
+    number_puzzles: usize,
-    threads: i32,
+    max_hints: u64,
+    threads: u64,
     debug: bool,
     solve_controller: SolveController,
     difficulty: Difficulty,
-) -> (Option<(Grid, SolveStatistics, i32)>, i32) {
+) -> Vec<GeneratedGrid> {
     let mut thread_rng = thread_rng();
     let (transmitter, receiver) = mpsc::channel();
-    let mut remaining_attempts = max_attempts;
 
-    let should_stop = AtomicBool::new(false);
+    let attempts_left = AtomicI64::new(max_attempts as i64);
-    let should_stop = Arc::new(should_stop);
+    let attempts_left = Arc::new(attempts_left);
+
+    let puzzles_left = AtomicI64::new(number_puzzles as i64);
+    let puzzles_left = Arc::new(puzzles_left);
 
     for i in 0..threads {
         let cloned_transmitter = mpsc::Sender::clone(&transmitter);
         let mut rng = SmallRng::from_rng(&mut thread_rng).unwrap();
-        let thread_attempts = remaining_attempts / (threads - i);
+        let attempts_left = Arc::clone(&attempts_left);
-        remaining_attempts -= thread_attempts;
+        let puzzles_left = Arc::clone(&puzzles_left);
-        let should_stop = Arc::clone(&should_stop);
 
         thread::spawn(move || {
             if debug {
-                println!("Thread {} spawned with {} max attempts", i, thread_attempts);
+                println!("Thread {} spawned", i);
             }
 
-            let should_stop = &*should_stop;
+            let found_puzzles = get_puzzle_matching_conditions(
-            let (result, num_attempts) = get_puzzle_matching_conditions(
                 &mut rng,
                 &difficulty,
                 &solve_controller,
-                thread_attempts,
                 max_hints,
-                should_stop,
+                &*puzzles_left,
+                &*attempts_left,
                 debug,
             );
 
-            let mut result_was_some = false;
+            let num_puzzles_found = found_puzzles.len();
-            let result = match result {
+            cloned_transmitter.send(found_puzzles).unwrap();
-                None => None,
-                Some((grid, solve_statistics, num_hints)) => {
-                    result_was_some = true;
-                    Some((SafeGridWrapper(grid), solve_statistics, num_hints))
-                }
-            };
-
-            cloned_transmitter.send((result, num_attempts)).unwrap();
 
             if debug {
                 println!(
-                    "Thread {}, terminated having run {} attempts; did send result: {}",
+                    "Thread {} terminated having found {} puzzles",
-                    i, num_attempts, result_was_some
+                    i, num_puzzles_found
                 );
             }
         });
     }
 
     let mut threads_running = threads;
-    let mut attempt_count = 0;
+    let mut all_puzzles_found = Vec::new();
-    let mut result_to_return = None;
 
     while threads_running > 0 {
-        let signal = receiver.recv().unwrap(); // Not sure what errors can result here but they are unexpected and deserve a panic
+        let mut thread_found_puzzles = receiver.recv().unwrap(); // Not sure what errors can result here but they are unexpected and deserve a panic
         threads_running -= 1;
+        all_puzzles_found.append(&mut thread_found_puzzles);
 
-        let (result, attempts) = signal;
-        attempt_count += attempts;
-
-        if let Some((safe_grid, solve_statistics, num_hints)) = result {
-            result_to_return = Some((safe_grid.0, solve_statistics, num_hints));
-            should_stop.store(true, Ordering::Relaxed);
-        }
     }
 
-    (result_to_return, attempt_count)
+    if debug {
+        println!("Stopping with {} attempts left and {} puzzles left.", attempts_left.load(Ordering::Relaxed), puzzles_left.load(Ordering::Relaxed));
+    }
+
+
+    all_puzzles_found
 }
 
+
 fn get_puzzle_matching_conditions(
     rng: &mut SmallRng,
     difficulty: &Difficulty,
     solve_controller: &SolveController,
-    max_attempts: i32,
+    max_hints: u64,
-    max_hints: i32,
+    puzzles_left: &AtomicI64,
-    should_stop: &AtomicBool,
+    attempts_left: &AtomicI64,
     debug: bool,
-) -> (Option<(Grid, SolveStatistics, i32)>, i32) {
+) -> Vec<GeneratedGrid> {
-    let mut num_attempts = 0;
 
-    while num_attempts < max_attempts && !should_stop.load(Ordering::Relaxed) {
+    let mut generated_grids: Vec<GeneratedGrid> = Vec::new();
-        let (grid, num_hints, solve_statistics) =
+
+    while attempts_left.fetch_sub(1, Ordering::SeqCst) > 0 && puzzles_left.load(Ordering::SeqCst) > 0 {
+        let (grid, num_hints, statistics) =
             sudoku_solver::generator::generate_grid(rng, &solve_controller);
-        num_attempts += 1;
 
         if debug {
-            println!("Found puzzle with {:#?}", solve_statistics);
+            println!("Found puzzle with {:#?}", statistics);
         }
 
-        if difficulty.meets_minimum_requirements(&solve_statistics) && num_hints <= max_hints {
+        if difficulty.meets_minimum_requirements(&statistics) && num_hints <= max_hints {
-            return (Some((grid, solve_statistics, num_hints)), num_attempts);
+            puzzles_left.fetch_sub(1, Ordering::SeqCst);
+            generated_grids.push(GeneratedGrid{
+                grid,
+                statistics,
+                num_hints
+            });
         }
     }
 
-    (None, num_attempts)
+    generated_grids
 }
 
-fn save_grid_csv(grid: &Grid, filename: &str) -> Result<(), Box<dyn Error>> {
+fn save_grids_csv(grids: &Vec<Grid>, filename: &str) -> Result<(), Box<dyn Error>> {
     // Not using the csv crate for writing because it's being difficult and won't accept raw integers
     let mut file = std::fs::File::create(filename)?;
 
+    for grid in grids.iter() {
         for x in 0..9 {
             for y in 0..9 {
                 let cell = grid.get(x, y).unwrap();
@@ -347,10 +343,15 @@ fn save_grid_csv(grid: &Grid, filename: &str) -> Result<(), Box<dyn Error>> {
                 if y < 8 {
                     text.push(',');
                 }
-            file.write_all(text.as_bytes())?;
+                //file.write_all(text.as_bytes())?;
+                file.write(text.as_bytes())?;
             }
-        file.write_all(b"\n")?;
+            file.write(b"\n")?;
         }
+        file.write(b"\n")?;
+    }
+
+    file.flush()?;
 
     Ok(())
 }

src/generator.rs

@@ -128,7 +128,7 @@ impl Section {
 pub fn generate_grid(
     rng: &mut SmallRng,
     solve_controller: &SolveController,
-) -> (Grid, i32, SolveStatistics) {
+) -> (Grid, u64, SolveStatistics) {
     let mut grid = generate_completed_grid(rng);
     let mut num_hints = 81;
 

src/pdf.rs

@@ -9,19 +9,47 @@ const GRID_DIMENSION: f64 = 190.0;
 
 const A4: (Mm, Mm) = (Mm(215.0), Mm(279.0));
 
-pub fn draw_grid(
+pub fn draw_grids(
-    grid: &Grid,
+    grids: &Vec<Grid>,
     filename: &str,
     print_possibilities: bool,
 ) -> Result<(), Box<dyn std::error::Error>> {
-    let (doc, page1, layer1) = PdfDocument::new("Sudoku Puzzle", A4.0, A4.1, "Layer 1");
+    let (doc, page1_index, layer1_index) = PdfDocument::new("Sudoku Puzzle", A4.0, A4.1, "Puzzle 1");
-    let layer = doc.get_page(page1).get_layer(layer1);
-
     let font = doc.add_builtin_font(BuiltinFont::HelveticaBold)?;
+
+    for (i, grid) in grids.iter().enumerate() {
+        let (page_index, layer_index) = match i {
+            0 => {
+                (page1_index, layer1_index)
+            },
+            _ => {
+                doc.add_page(A4.0, A4.1, format!("Puzzle {}", i+1))
+            }
+        };
+
+        let layer = doc.get_page(page_index).get_layer(layer_index);
+
+        draw_grid(grid, &layer, print_possibilities, &font)?;
+
+    }
+
+    doc.save(&mut BufWriter::new(File::create(filename)?))?;
+
+    Result::Ok(())
+
+}
+
+pub fn draw_grid(
+    grid: &Grid,
+    layer: &PdfLayerReference,
+    print_possibilities: bool,
+    font: &IndirectFontRef,
+) -> Result<(), Box<dyn std::error::Error>> {
+
     let fixed_value_font_size = 45.0;
     let possibility_font_size = 12.0;
 
-    draw_empty_grid(&layer);
+    draw_empty_grid(layer);
 
     // x represents position on left-right scale
     // y represents position on up-down scale
@@ -65,8 +93,6 @@ pub fn draw_grid(
         }
     }
 
-    doc.save(&mut BufWriter::new(File::create(filename)?))?;
-
     Ok(())
 }