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Improved reduce() efficiently slightly
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@michael-wsp
michael-wsp committed Apr 20, 2024
1 parent d320b48 commit 50d62bb
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Showing 2 changed files with 87 additions and 84 deletions.
156 changes: 83 additions & 73 deletions src/game/crossteaser/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -124,30 +124,30 @@ const ORIENTATION_MAP: [u64; 24] = [
/// NOTE: This can likely be improved by combining transformations in a
/// clever way.
const TRANSFORM_MAP: [u64; 24] = [
0b0, // 0
0b000_01, // 1
0b000_11, // 2
0b000_01_000_01, // 3
0b010_01, // 4
0b010_01_001_01, // 5
0b000_11_010_01, // 6
0b000_01_000_01_011_11, // 7
0b010_01_000_01, // 8
0b010_01_001_01_000_01, // 9
0b000_11_010_01_101_11, // 10
0b000_11_001_11, // 11
0b100_11, // 12
0b100_11_011_01, // 13
0b100_11_010_11, // 14
0b000_01_000_01_001_01, // 15
0b000_11_010_11, // 16
0b010_11, // 17
0b000_01_000_01_011_01, // 18
0b000_01_011_01, // 19
0b100_11_011_01_100_11, // 20
0b010_01_010_01, // 21
0b001_01_001_01, // 22
0b000_01_011_01_011_01, // 23
0b0, // 0
0b000_01, // 1
0b000_11, // 2
0b000_10, // 3
0b010_01, // 4
0b010_01_001_01, // 5
0b000_11_010_01, // 6
0b000_10_011_11, // 7
0b010_01_000_01, // 8
0b000_10_001_11, // 9
0b000_10_001_11, // 10
0b000_11_001_11, // 11
0b100_11, // 12
0b100_11_011_01, // 13
0b100_11_010_11, // 14
0b000_10_001_01, // 15
0b000_11_010_11, // 16
0b010_11, // 17
0b000_10_011_01, // 18
0b000_01_011_01, // 19
0b100_10_101_01, // 20
0b010_10, // 21
0b001_10, // 22
0b000_01_011_10, // 23
];

// Constant bitmask values that will be commonly used for hashing/unhashing
Expand Down Expand Up @@ -218,18 +218,6 @@ impl Session {
return hashed_state;
}

/// Inefficient hash function
/// Not in use
fn _hash_old(&self, s: &UnhashedState) -> State {
let mut new_s: State = s.free;
let mut shift: u64 = EMPTY_BITS;
for o in &s.pieces {
new_s |= hash_orientation(o) << shift;
shift += PIECE_BITS;
}
return new_s;
}

/// Reverse of hash(), extracts the orientation vector and empty space from
/// a State.
fn unhash(&self, s: State) -> UnhashedState {
Expand All @@ -251,26 +239,6 @@ impl Session {
};
}

/// Inefficient unhash function
/// Not in use
fn _unhash_old(&self, s: State) -> UnhashedState {
let num_pieces: u64 = self.get_pieces();
let mut s_tmp: u64 = s;
let mut curr: u64;
let empty: u64 = s & EMPTY_BITMASK;
s_tmp >>= EMPTY_BITS;
let mut rep: Vec<Orientation> = Vec::new();
for i in 0..num_pieces {
curr = s_tmp & PIECE_BITMASK;
rep.push(unhash_orientation(curr));
s_tmp >>= PIECE_BITS;
}
return UnhashedState {
pieces: rep,
free: empty,
};
}

/// Adjusts the entire board with a "right" move
/// Adjusts empty space accordingly
/// Makes use of mov::right()
Expand Down Expand Up @@ -357,7 +325,6 @@ impl Session {
};
}

/// Not in use
fn board_180(&self, s: &UnhashedState) -> UnhashedState {
let mut rep: Vec<Orientation> = Vec::new();
for i in (0..s.pieces.len()).rev() {
Expand All @@ -370,7 +337,6 @@ impl Session {
};
}

/// Not in use
fn flip_board(&self, s: &UnhashedState) -> UnhashedState {
let mut rep: Vec<Orientation> = Vec::new();
for row in 0..self.length {
Expand All @@ -393,7 +359,11 @@ impl Session {
}

fn flip_90(&self, s: &UnhashedState) -> UnhashedState {
return self.board_cw(&self.flip_board(s));
if self.width == self.length {
return self.board_cw(&self.flip_board(s));
} else {
return s.deep_copy();
}
}

/// Applies a sequence of transformations on an orientation
Expand All @@ -415,6 +385,8 @@ impl Session {
t_list >>= 3;
if transform == 0b01 {
new_o = mov::cw_on_axis(&new_o, axis);
} else if transform == 0b10 {
new_o = mov::axis_180(&new_o, axis);
} else if transform == 0b11 {
new_o = mov::cw_on_axis(&new_o, 5 - axis);
}
Expand All @@ -423,12 +395,15 @@ impl Session {
}

/// Finds the canonical position of a given state
/// It does so by reducing the first piece to orientation 0,
/// It does so by reducing the last piece to orientation 0,
/// and adjusting the rest of the pieces equivalently
/// Uses apply_transformations() to properly adjust pieces
fn canonical(&self, s: &UnhashedState) -> UnhashedState {
fn reduce(&self, s: &UnhashedState) -> UnhashedState {
let mut new_pieces: Vec<Orientation> = Vec::new();
let pos: u64 = hash_orientation(&s.pieces.last().unwrap());
if pos == 0 {
return s.deep_copy();
}
let transform_list: u64 = TRANSFORM_MAP[pos as usize];
for o in &s.pieces {
new_pieces.push(self.apply_transformations(o, transform_list));
Expand All @@ -439,14 +414,29 @@ impl Session {
};
}

fn canonical_sym(&self, s: &UnhashedState) -> State {
let mut sym_list: Vec<State> = Vec::new();
sym_list.push(self.hash(s));
let flipped: UnhashedState = self.flip_90(s);
sym_list.push(self.hash(&flipped));
sym_list.push(self.hash(&self.canonical(&self.board_180(s))));
sym_list.push(self.hash(&self.canonical(&self.board_180(&flipped))));
return *sym_list.iter().min().unwrap();
fn board_sym(&self, s: &UnhashedState) -> UnhashedState {
let mut sym_list: Vec<UnhashedState> = Vec::new();
sym_list.push(s.deep_copy());
sym_list.push(self.board_180(s));
if self.width == self.length {
let flipped: UnhashedState = self.flip_90(s);
sym_list.push(flipped.deep_copy());
sym_list.push(self.board_180(&flipped));
}
let mut min: u64 = self.hash(&sym_list[0]);
let mut min_i: usize = 0;
for i in 0..sym_list.len() {
let curr: u64 = self.hash(&sym_list[i]);
if curr < min {
min_i = i;
min = curr;
}
}
return sym_list.remove(min_i);
}

fn canonical(&self, s: &UnhashedState) -> UnhashedState {
return self.reduce(&self.board_sym(s));
}
}

Expand Down Expand Up @@ -569,6 +559,14 @@ mod mov {
};
}

pub fn right_180(o: &Orientation) -> Orientation {
return Orientation {
front: 5 - o.front,
top: 5 - o.top,
right: o.right,
};
}

/// Performs a clowckwise orientation on an orientation
/// along the specified axis.
/// I am trying to figure out a way to make this faster.
Expand All @@ -589,6 +587,18 @@ mod mov {
panic!("Invalid Orientation");
}
}

pub fn axis_180(o: &Orientation, axis: u64) -> Orientation {
if axis == o.front || axis == 5 - o.front {
return front_180(o);
} else if axis == o.top || axis == 5 - o.top {
return top_180(o);
} else if axis == o.right || axis == 5 - o.right {
return right_180(o);
} else {
panic!("Invalid Orientation");
}
}
}

/// Represents an instance of a Crossteaser game session, which is specific to
Expand Down Expand Up @@ -654,16 +664,16 @@ impl DTransition for Session {
let s: UnhashedState = self.unhash(state);
let mut states: Vec<State> = Vec::new();
if s.free / self.width != self.length - 1 {
states.push(self.canonical_sym(&self.board_up(&s)));
states.push(self.hash(&self.canonical(&self.board_up(&s))));
}
if s.free / self.width != 0 {
states.push(self.canonical_sym(&self.board_down(&s)));
states.push(self.hash(&self.canonical(&self.board_down(&s))));
}
if s.free % self.width != 0 {
states.push(self.canonical_sym(&self.board_right(&s)));
states.push(self.hash(&self.canonical(&self.board_right(&s))));
}
if s.free % self.width != self.width - 1 {
states.push(self.canonical_sym(&self.board_left(&s)));
states.push(self.hash(&self.canonical(&self.board_left(&s))));
}
return states;
}
Expand Down
15 changes: 4 additions & 11 deletions src/game/crossteaser/states.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,25 +40,18 @@ mod test {
s.pieces
.push(unhash_orientation(0));
}

let mut solved: HashSet<State> = HashSet::new();
let mut found: HashSet<State> = HashSet::new();
let mut unsolved: Vec<State> = Vec::new();
unsolved.push(session.hash(&s));
let mut count: u64 = 0;
while !unsolved.is_empty() {
for i in 0..1000 {
let s: State = unsolved.pop().unwrap();
solved.insert(s);
found.insert(s);
let f: Vec<State> = session.prograde(s);
for state in f {
if !solved.contains(&state) {
if !found.contains(&state) {
unsolved.push(state);
}
}
count += 1;
if count % 100000 == 0 {
println!("discovered {}", count);
}
}
println!("{}", solved.len());
}
}

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