Optimisation, formatting changes

README.md

@@ -1,3 +0,0 @@
-# Deadlock and Optimizations
-
-Explain your optimizations if applicable

report.md

@@ -0,0 +1,140 @@
+# Deadlock and Optimizations
+
+## Deadlock detections
+### Simple corner deadlock detection
+The simple corner deadlock that was already implemented aims to prevent a box
+from being pushed into a corner. If it is pushed into a corner, it is
+inaccessible and immovable, thus rendering that state unsolvable.
+
+### Freeze deadlock detection
+Described 
+[here](http://sokobano.de/wiki/index.php?title=Deadlocks#Freeze_deadlocks), 
+freeze detection is about preventing two boxes from being adjacent against a 
+wall when there is no goal in that location. This deadlock detection was chosen
+as there are many scenarios (such as in test_maps/test_map2 and 
+test_maps/test_map3) where there are multiple boxes and a complex map layout.
+This deadlock detection saves a small amount time and reduces the number of 
+nodes that are expanded.
+
+The code for this detection is contained in `utils.c`, from lines 321 - 480. 
+The function `freeze_deadlock()` is used to check if there is a box adjacent to
+the player, and if there is, then the function `adjacent_box_check()` is called
+to check for the freeze deadlock scenario.
+
+## Optimisation results
+These results show the impact of implementing the freeze deadlock detection.
+
+Hardware used:
+- CPU: AMD Ryzen 4800U
+- GPU: AMD Radeon RX Vega 8
+- Memory: 16GB
+
+### Summary of optimisation
+The following table summarises some of the key statistics prior to implementing
+freeze deadlock detection, and after implementing freeze deadlock detection.
+
+Test: test_map1
+
+| Statistic      | Before implementation | After implementation | % improvement |
+|----------------|-----------------------|----------------------|---------------|
+| Expanded nodes | 13                    | 13                   | 0.00          |
+| Time (s)       | 0.050106              | 0.047723             | 4.76          |
+
+
+Test: test_map2
+
+| Statistic      | Before implementation | After implementation | % improvement |
+|----------------|-----------------------|----------------------|---------------|
+| Expanded nodes | 978745                | 944140               | 3.54          |
+| Time           | 3.456764              | 3.227685             | 6.63          |
+
+Test: test_map3
+
+| Statistic      | Before implementation | After implementation | % improvement |
+|----------------|-----------------------|----------------------|---------------|
+| Expanded nodes | 230041                | 215253               | 6.43          |
+| Time           | 1.828733              | 1.680901             | 8.08          |
+
+### Full output (before optimisation)
+```
+$ ./sokoban -s test_maps/test_map1
+
+SOLUTION:
+rrRRRR
+
+STATS:
+	Expanded nodes: 13
+	Generated nodes: 48
+	Duplicated nodes: 8
+	Solution Length: 6
+	Expanded/seconds: 259
+	Time (seconds): 0.050106
+
+$ ./sokoban -s test_maps/test_map2
+
+SOLUTION:
+rrrrrrdrdLLLLLLLLullluRRRRRRRururRRRRRRRRRR
+
+STATS:
+	Expanded nodes: 978745
+	Generated nodes: 3914976
+	Duplicated nodes: 2288345
+	Solution Length: 43
+	Expanded/seconds: 283139
+	Time (seconds): 3.456764
+
+$ ./sokoban -s test_maps/test_map3
+
+SOLUTION:
+drdrdrdrrruuuuuulllllddrdrdrDulululldRdRdrdRRllululuurdrdrDululldRuuluurrrrrdddddrddlUUUUUUruLLLLLulDDdrdddrdRRlluluurdrDulldruluulldRuuurrrrrdddddrddlUUUUUUruLLLLLulDDdrdrdddRRlluurDldRuulululldRdRluuuurrrrrdddddrddlUUUUUUruLLLLLulDDdrdrdrddRluulululldRdRluuuurrrrrdddddrddlUUUUUUruLLLLLulDD
+
+STATS:
+	Expanded nodes: 230041
+	Generated nodes: 920160
+	Duplicated nodes: 331571
+	Solution Length: 292
+	Expanded/seconds: 125792
+	Time (seconds): 1.828733
+```
+
+### Full output (after optimisation)
+```
+$ ./sokoban -s test_maps/test_map1
+
+SOLUTION:
+rrRRRR
+
+STATS:
+	Expanded nodes: 13
+	Generated nodes: 48
+	Duplicated nodes: 8
+	Solution Length: 6
+	Expanded/seconds: 272
+	Time (seconds): 0.047723
+
+$ ./sokoban -s test_maps/test_map2
+
+SOLUTION:
+rrrrrrdrdLLLLLLLLullluRRRRRRRurruRRRRRRRRRR
+
+STATS:
+	Expanded nodes: 944140
+	Generated nodes: 3776556
+	Duplicated nodes: 2199712
+	Solution Length: 43
+	Expanded/seconds: 292513
+	Time (seconds): 3.227685
+
+$ ./sokoban -s test_maps/test_map3
+
+SOLUTION:
+drdrdrdrrruuuuuulllllddrdrdrDulululldRdRdrdRRllululuurdrdrDululldRuuluurrrrrdddddrddlUUUUUUruLLLLLulDDdrdddrdRRlluluurdrDulldruululldRuuurrrrrdddddrddlUUUUUUruLLLLLulDDdrdrdddRRlluurDldRluuululldRdRluuuurrrrrdddddrddlUUUUUUruLLLLLulDDdrdrdrddRluulululldRdRluuuurrrrrdddddrddlUUUUUUruLLLLLulDD
+
+STATS:
+	Expanded nodes: 215253
+	Generated nodes: 861008
+	Duplicated nodes: 309654
+	Solution Length: 292
+	Expanded/seconds: 128058
+	Time (seconds): 1.680901
+```

solution.txt

@@ -1 +0,0 @@
-rrRlllllL

src/ai/ai.c

@@ -73,7 +73,7 @@ void copy_state(sokoban_t *init_data, state_t *dst, state_t *src) {
  * Create the initial node
  */
 node_t *create_init_node(sokoban_t *init_data) {
-	node_t  *new_n = (node_t *) malloc(sizeof(node_t));
+	node_t *new_n = malloc(sizeof(node_t));
 
 	new_n->parent = NULL;	
 	new_n->priority = 0;
@@ -98,7 +98,7 @@ node_t *create_init_node(sokoban_t *init_data) {
  * Create the a node from a parent node
  */
 node_t *create_node(sokoban_t *init_data, node_t *parent) {
-	node_t  *new_n = (node_t *) malloc(sizeof(node_t));
+	node_t *new_n = malloc(sizeof(*new_n));
 	new_n->parent = parent;
 	new_n->depth = parent->depth + 1;
 	copy_state(init_data, &(new_n->state), &(parent->state));
@@ -189,7 +189,8 @@ void find_solution(sokoban_t *init_data, bool show_solution) {
 	// Choose initial capacity of PRIME NUMBER 
 	// Specify the size of the keys and values you want to store once 
 	// The Hash Table only accept a 1D key and value.
-	ht_setup(&hashTable, sizeof(int8_t) * init_data->num_chars_map, sizeof(int8_t) * init_data->num_chars_map, 16769023);
+	ht_setup(&hashTable, sizeof(int8_t) * init_data->num_chars_map, \
+		sizeof(int8_t) * init_data->num_chars_map, 16769023);
 
 	// Data structure to create a 1D representation of the map
 	// Needed to interact with the hash table
@@ -200,8 +201,8 @@ void find_solution(sokoban_t *init_data, bool show_solution) {
 
 	// Initialize expanded nodes table. 
 	// This table will be used to free your memory once a solution is found
-	expanded_nodes_table = (node_t **) malloc(sizeof(node_t *) * expanded_nodes_table_size); 
-
+	expanded_nodes_table = malloc(sizeof(*expanded_nodes_table) * \
+		expanded_nodes_table_size); 
 
 	// Add the initial node
 	node_t *n = create_init_node(init_data);
@@ -221,13 +222,17 @@ void find_solution(sokoban_t *init_data, bool show_solution) {
 		}
 
 		for (move_t action = left; action <= down; action++) {
-			node_t *new = malloc(sizeof(*new));
+			node_t *new;
 			bool player_moved = applyAction(init_data, n, &new, action);
 			generated_nodes += 1;
-			if (!player_moved || simple_corner_deadlock(init_data, &(new->state))) {
+
+			if (!player_moved || freeze_deadlock(init_data, &(new->state)) || \
+				simple_corner_deadlock(init_data, &(new->state))) {
+
 				for (int i = 0; i < init_data->lines; i++) {
 					free(new->state.map[i]);
 				}
+				
 				free(new->state.map);
 				free(new);
 				continue;
@@ -256,17 +261,8 @@ void find_solution(sokoban_t *init_data, bool show_solution) {
 	free_memory(expanded_nodes, init_data->lines);
 	free(flat_map);
 
-	// Free initial data
-	for (int i = 0; i < init_data->lines; i++) {
-		free((init_data->map)[i]);
-		free((init_data->map_save)[i]);
-	}
-	free(init_data->map);
-	free(init_data->map_save);
-	free(init_data->buffer);
-
 	// Free priority queue
-	for (int i = pq.count; i > 0; i--) {
+	for (int i = 0; i < pq.count; i++) {
 		for (int j = 0; j < init_data->lines; j++) {
 			if (pq.heaparr[i]->state.map[j]) {
 				free(pq.heaparr[i]->state.map[j]);
@@ -326,4 +322,13 @@ void solve(char const *path, bool show_solution) {
 	sokoban = find_player(sokoban);
 	
 	find_solution(&sokoban, show_solution);
+
+	// Free initial data
+	for (int i = 0; i < sokoban.lines; i++) {
+		free((sokoban.map)[i]);
+		free((sokoban.map_save)[i]);
+	}
+	free(sokoban.map);
+	free(sokoban.map_save);
+	free(sokoban.buffer);
 }

src/ai/utils.c

@@ -318,6 +318,167 @@ bool simple_corner_deadlock(sokoban_t *init_data, state_t *state) {
     return deadlock;
 }
 
+bool adjacent_box_check(int x, int y, sokoban_t *init_data, state_t *state) {
+	/* The outside if statement for each example checks to see if the indices 
+	 * are within the map to prevent out-of-bounds errors.
+	 * The inside if statement then checks if the current state matches the 
+	 * example.
+	 */
+
+	/*	Example 1:
+	 *  #  #  #  #  #
+	 *	#     $
+	 *	#        $
+	 *  #        @
+	 *  #
+	 */
+	if ((y - 2 >= 0) && (x < (int) strlen((state->map)[y - 2])) && \
+		(x - 1 < (int) strlen((state->map)[y - 1]))) {
+		if (state->map[y - 1][x - 1] == '$' && state->map[y - 2][x] == '#' && \
+			state->map[y - 2][x - 1] == '#' && \
+			!is_goal_loc(state->player_y, state->player_x, init_data)) {
+			return true;
+		}
+	}
+
+	/*	Example 2:
+	 *  #  #  #  #  #
+	 *	#        $
+	 *	#     $
+	 *  #     @
+	 *  #
+	 */
+	if ((y - 2 >= 0) && (x + 1 < (int) strlen((state->map)[y - 2])) && \
+		(x + 1 < (int) strlen((state->map)[y - 1]))) {
+		if (state->map[y - 1][x + 1] == '$' && state->map[y - 2][x] == '#' && \
+			state->map[y - 2][x + 1] == '#' && \
+			!is_goal_loc(state->player_y, state->player_x, init_data)) {
+			return true;
+		}
+	}
+
+	/*	Example 3:
+	 *  #  #  #  #  #
+	 *	#
+	 *	#  $
+	 *  #     $  @
+	 *  #
+	 */
+	if ((y < init_data->lines) && (x - 1 < (int) strlen(state->map[y - 1]))) {
+		if (state->map[y - 1][x - 1] == '$' && state->map[y][x - 2] == '#' && \
+			state->map[y - 1][x - 2] == '#' && \
+			!is_goal_loc(state->player_y, state->player_x, init_data)) {
+			return true;
+		}
+	}
+
+	/*	Example 4:
+	 *  #  #  #  #  #
+	 *	#
+	 *	#     $  @
+	 *  #  $
+	 *  #
+	 */
+	if ((y + 1 < init_data->lines) && (x - 1 < (int) strlen(state->map[y + 1]))) {
+		if (state->map[y + 1][x - 1] == '$' && state->map[y][x - 2] == '#' && \
+			state->map[y + 1][x - 2] == '#' && \
+			!is_goal_loc(state->player_y, state->player_x, init_data)) {
+			return true;
+		}
+	}
+
+	/*	Example 5:
+	 *              #
+	 *              #
+	 *	         $  #
+	 *	   @  $     #
+	 *              #
+	 *  #  #  #  #  #
+	 */
+	if ((y < init_data->lines) && (x + 2 < (int) strlen(state->map[y - 1])) && \
+		(x + 2 < (int) strlen(state->map[y]))) {
+		if (state->map[y - 1][x + 1] == '$' && state->map[y][x + 2] == '#' && \
+			state->map[y - 1][x + 2] == '#' && \
+			!is_goal_loc(state->player_y, state->player_x, init_data)) {
+			return true;
+		}
+	}
+	/*	Example 6:
+	 *              #
+	 *     @  $     #
+	 *	         $  #
+	 *	            #
+	 *  #  #  #  #  #
+	 */
+	if ((y - 1 < init_data->lines) && (x + 2 < (int) strlen(state->map[y - 1])) && \
+		(x + 2 < (int) strlen(state->map[y]))) {
+		if (state->map[y - 1][x + 1] == '$' && state->map[y][x + 2] == '#' && \
+			state->map[y - 1][x + 2] == '#' && \
+			!is_goal_loc(state->player_y, state->player_x, init_data)) {
+			return true;
+		}
+	}
+
+	/*	Example 7:
+	 *              #
+	 *        @     #
+	 *	      $     #
+	 *	   $        #
+	 *  #  #  #  #  #
+	 */
+	if ((y + 2 < init_data->lines) && (x < (int) strlen((state->map)[y + 2])) && \
+		(x - 1 < (int) strlen((state->map)[y + 1]))) {
+		if (state->map[y + 1][x - 1] == '$' && state->map[y + 2][x] == '#' && \
+			state->map[y + 2][x - 1] == '#' && \
+			!is_goal_loc(state->player_y, state->player_x, init_data)) {
+			return true;
+		}
+	}
+
+	/*	Example 8:
+	 *              #
+	 *     @        #
+	 *	   $        #
+	 *	      $     #
+	 *  #  #  #  #  #
+	 */
+	if ((y + 2 < init_data->lines) && (x + 1 < (int) strlen((state->map)[y + 2])) && \
+		(x + 1 < (int) strlen((state->map)[y + 1]))) {
+		if (state->map[y + 1][x + 1] == '$' && state->map[y + 2][x] == '#' && \
+			state->map[y + 2][x + 1] == '#' && \
+			!is_goal_loc(state->player_y, state->player_x, init_data)) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+bool freeze_deadlock(sokoban_t *init_data, state_t *state) {
+	bool deadlock = false;
+
+	int x = state->player_x;
+	int y = state->player_y;
+
+	if (state->map[y - 1][x] == '$') {
+		deadlock = adjacent_box_check(x, y - 1, init_data, state);
+	}
+
+	if (state->map[y + 1][x] == '$') {
+		deadlock = adjacent_box_check(x, y + 1, init_data, state);
+	}
+
+	if (state->map[y][x - 1] == '$') {
+		deadlock = adjacent_box_check(x - 1, y, init_data, state);
+	}
+
+	if (state->map[y][x + 1] == '$') {
+		deadlock = adjacent_box_check(x + 1, y, init_data, state);
+	}
+
+	return deadlock;
+}
+
 /*****************************************************************************
 * Function:    winning_condition                                             *
 * Parameters:  sokoban_t *init_data, state_t *state                          *
@@ -340,8 +501,8 @@ bool winning_condition(sokoban_t *init_data, state_t *state) {
 void play_solution(sokoban_t init_data, char *solution ) {
 	SCREEN *mainScreen = newterm(TERMINAL_TYPE, stdout, stdin);
 	set_term(mainScreen);
-	int cols = 1;
 
+	int cols = 1;
 	for(int i = 0; i < init_data.lines; i++){
 		if(strlen(init_data.map[i]) > (size_t) cols){
 			cols = strlen(init_data.map[i]);

src/ai/utils.h

@@ -44,6 +44,10 @@ bool execute_move_t(sokoban_t *init_data, state_t *state, move_t move);
 
 bool simple_corner_deadlock(sokoban_t *init_data, state_t *state);
 
+bool adjacent_box_check(int x, int y, sokoban_t *init_data, state_t *state);
+
+bool freeze_deadlock(sokoban_t *init_data, state_t *state);
+
 bool winning_condition(sokoban_t *init_data, state_t *state);
 
 void play_solution(sokoban_t init_data, char* solution);