Update.
[picoclvr.git] / main.py
diff --git a/main.py b/main.py
index e741094..9dee679 100755 (executable)
--- a/main.py
+++ b/main.py
@@ -8,7 +8,7 @@
 # torch.backends.cuda.matmul.allow_tf23
 # torch.autocast(torch.bfloat16)
 
-import math, sys, argparse, time, tqdm, itertools, os
+import math, sys, argparse, time, tqdm, os
 
 import torch, torchvision
 from torch import nn
@@ -27,28 +27,36 @@ else:
 ######################################################################
 
 parser = argparse.ArgumentParser(
-    description="An implementation of GPT with cache to solve a toy geometric reasoning task."
+    description="An implementation of GPT with cache.",
+    formatter_class=argparse.ArgumentDefaultsHelpFormatter,
 )
 
-parser.add_argument("--log_filename", type=str, default="train.log")
+parser.add_argument(
+    "--task",
+    type=str,
+    default="picoclvr",
+    help="picoclvr, mnist, maze, snake, stack, expr",
+)
+
+parser.add_argument("--log_filename", type=str, default="train.log", help=" ")
 
-parser.add_argument("--result_dir", type=str, default="results_default")
+parser.add_argument("--result_dir", type=str, default=None)
 
 parser.add_argument("--seed", type=int, default=0)
 
-parser.add_argument("--nb_epochs", type=int, default=25)
+parser.add_argument("--nb_epochs", type=int, default=None)
 
-parser.add_argument("--batch_size", type=int, default=100)
+parser.add_argument("--batch_size", type=int, default=None)
 
-parser.add_argument("--data_size", type=int, default=-1)
+parser.add_argument("--nb_train_samples", type=int, default=None)
+
+parser.add_argument("--nb_test_samples", type=int, default=None)
 
 parser.add_argument("--optim", type=str, default="adam")
 
-parser.add_argument("--learning_rate", type=float, default=1e-3)
+parser.add_argument("--learning_rate", type=float, default=1e-4)
 
-parser.add_argument(
-    "--learning_rate_schedule", type=str, default="10: 2e-4,20: 4e-5,30: 8e-6"
-)
+parser.add_argument("--learning_rate_schedule", type=str, default="10: 2e-5,30: 4e-6")
 
 parser.add_argument("--dim_model", type=int, default=512)
 
@@ -73,19 +81,108 @@ parser.add_argument("--checkpoint_name", type=str, default="checkpoint.pth")
 ##############################
 # picoclvr options
 
-parser.add_argument("--nb_colors", type=int, default=5)
+parser.add_argument("--picoclvr_nb_colors", type=int, default=5)
+
+parser.add_argument("--picoclvr_height", type=int, default=12)
+
+parser.add_argument("--picoclvr_width", type=int, default=16)
+
+parser.add_argument("--picocvlr_prune_properties", type=str, default="none")
+
+##############################
+# Maze options
+
+parser.add_argument("--maze_height", type=int, default=13)
+
+parser.add_argument("--maze_width", type=int, default=21)
+
+parser.add_argument("--maze_nb_walls", type=int, default=15)
+
+##############################
+# Snake options
+
+parser.add_argument("--snake_height", type=int, default=6)
+
+parser.add_argument("--snake_width", type=int, default=8)
+
+parser.add_argument("--snake_nb_colors", type=int, default=5)
 
-parser.add_argument("--height", type=int, default=12)
+parser.add_argument("--snake_length", type=int, default=200)
 
-parser.add_argument("--width", type=int, default=16)
+##############################
+# Snake options
+
+parser.add_argument("--stack_nb_steps", type=int, default=100)
+
+parser.add_argument("--stack_nb_stacks", type=int, default=1)
+
+parser.add_argument("--stack_nb_digits", type=int, default=3)
+
+parser.add_argument("--stack_fraction_values_for_train", type=float, default=None)
 
-parser.add_argument("--prune_properties", type=str, default="none")
+##############################
+# Expr options
+
+parser.add_argument("--expr_nb_variables", type=int, default=5)
+
+parser.add_argument("--expr_sequence_length", type=int, default=30)
 
 ######################################################################
 
 args = parser.parse_args()
 
-assert args.prune_properties in {"none", "train+eval", "eval"}
+assert args.picocvlr_prune_properties in {"none", "train+eval", "eval"}
+
+if args.result_dir is None:
+    args.result_dir = f"results_{args.task}"
+
+######################################################################
+
+default_args = {
+    "picoclvr": {
+        "nb_epochs": 25,
+        "batch_size": 25,
+        "nb_train_samples": 250000,
+        "nb_test_samples": 10000,
+    },
+    "mnist": {
+        "nb_epochs": 25,
+        "batch_size": 10,
+        "nb_train_samples": 250000,
+        "nb_test_samples": 10000,
+    },
+    "maze": {
+        "nb_epochs": 25,
+        "batch_size": 25,
+        "nb_train_samples": 250000,
+        "nb_test_samples": 10000,
+    },
+    "snake": {
+        "nb_epochs": 5,
+        "batch_size": 25,
+        "nb_train_samples": 250000,
+        "nb_test_samples": 10000,
+    },
+    "stack": {
+        "nb_epochs": 5,
+        "batch_size": 25,
+        "nb_train_samples": 100000,
+        "nb_test_samples": 1000,
+    },
+    "expr": {
+        "nb_epochs": 50,
+        "batch_size": 25,
+        "nb_train_samples": 250000,
+        "nb_test_samples": 10000,
+    },
+}
+
+if args.task in default_args:
+    for k, v in default_args[args.task].items():
+        if getattr(args, k) is None:
+            setattr(args, k, v)
+
+######################################################################
 
 try:
     os.mkdir(args.result_dir)
@@ -124,11 +221,29 @@ for n in vars(args):
 ######################################################################
 
 
+# ra_mask is boolean, with 1s on the values to generate
+
+
 def masked_inplace_autoregression(
-    model, batch_size, input, ar_mask, forbidden_tokens=None, device=torch.device("cpu")
+    model,
+    batch_size,
+    input,
+    ar_mask,
+    forbidden_tokens=None,
+    progress_bar_desc="autoregression",
+    device=torch.device("cpu"),
 ):
+    batches = zip(input.split(batch_size), ar_mask.split(batch_size))
+
+    if progress_bar_desc is not None:
+        batches = tqdm.tqdm(
+            batches,
+            dynamic_ncols=True,
+            desc=progress_bar_desc,
+            total=input.size(0) // batch_size,
+        )
 
-    for input, ar_mask in zip(input.split(batch_size), ar_mask.split(batch_size)):
+    for input, ar_mask in batches:
         i = (ar_mask.sum(0) > 0).nonzero()
         if i.min() > 0:
             model(
@@ -167,7 +282,6 @@ import picoclvr
 
 
 class TaskPicoCLVR(Task):
-
     # Make a tensor from a list of strings
     def tensorize(self, descr):
         token_descr = [s.strip().split(" ") for s in descr]
@@ -265,6 +379,7 @@ class TaskPicoCLVR(Task):
                 input,
                 ar_masks,
                 forbidden_tokens,
+                progress_bar_desc=None,
                 device=self.device,
             )
             model.train(t)
@@ -277,6 +392,8 @@ class TaskPicoCLVR(Task):
 
     def __init__(
         self,
+        nb_train_samples,
+        nb_test_samples,
         batch_size,
         height,
         width,
@@ -298,12 +415,12 @@ class TaskPicoCLVR(Task):
         self.width = width
         self.batch_size = batch_size
         self.device = device
-        nb = args.data_size if args.data_size > 0 else 250000
         self.pruner_train = pruner_train
         self.pruner_eval = pruner_eval
 
         param = {
-            "nb": nb,
+            "nb_train_samples": nb_train_samples,
+            "nb_test_samples": nb_test_samples,
             "height": height,
             "width": width,
             "nb_colors": nb_colors,
@@ -311,11 +428,13 @@ class TaskPicoCLVR(Task):
             "rng_state": list(torch.get_rng_state()),
         }
 
-        log_string(f"generating {nb} samples (can take some time)")
+        log_string(
+            f"generating {nb_train_samples+nb_test_samples} samples (can take some time)"
+        )
         self.train_descr = generate_descr(
-            (nb * 4) // 5, "train", pruner=self.pruner_train
+            nb_train_samples, "train", pruner=self.pruner_train
         )
-        self.test_descr = generate_descr((nb * 1) // 5, "test", pruner=None)
+        self.test_descr = generate_descr(nb_test_samples, "test", pruner=None)
 
         # Build the tokenizer
         tokens = {"<nul>", "<img>"}
@@ -346,7 +465,6 @@ class TaskPicoCLVR(Task):
         return len(self.token2id)
 
     def compute_missing_properties(self, n_epoch, model, pruner=None):
-
         acc_nb_requested_properties = []
         acc_nb_missing_properties = []
         acc_nb_results = 0
@@ -385,7 +503,6 @@ class TaskPicoCLVR(Task):
     ######################################################################
 
     def produce_results(self, n_epoch, model):
-
         self.compute_missing_properties(n_epoch, model)
 
         if self.pruner_eval is not None:
@@ -440,36 +557,724 @@ class TaskPicoCLVR(Task):
                     0,
                 )
 
-        image_name = os.path.join(args.result_dir, f"result_{n_epoch:04d}.png")
+        image_name = os.path.join(args.result_dir, f"picoclvr_result_{n_epoch:04d}.png")
         torchvision.utils.save_image(
-            img / 255.0, image_name, nrow=nb_per_primer, padding=1, pad_value=1.0
+            img / 255.0, image_name, nrow=nb_per_primer, padding=1, pad_value=0.0
         )
         log_string(f"wrote {image_name}")
 
 
 ######################################################################
 
-log_string(f"device {device}")
 
+class TaskMNIST(Task):
+    def __init__(self, batch_size, device=torch.device("cpu")):
+        self.device = device
+        self.batch_size = batch_size
+
+    def batches(self, split="train"):
+        assert split in {"train", "test"}
+        data_set = torchvision.datasets.MNIST(
+            root="./data", train=(split == "train"), download=True
+        )
+        data_input = data_set.data.view(-1, 28 * 28).long()
+        if args.nb_train_samples is not None:
+            data_input = data_input[: args.nb_train_samples]
+        for batch in tqdm.tqdm(
+            data_input.split(self.batch_size), desc=f"epoch-{split}"
+        ):
+            yield batch
+
+    def vocabulary_size(self):
+        return 256
+
+    def produce_results(self, n_epoch, model):
+        results = torch.empty(64, 28 * 28, device=self.device, dtype=torch.int64)
+        ar_mask = torch.full_like(results, 1)
+        masked_inplace_autoregression(
+            model, self.batch_size, results, ar_mask, device=self.device
+        )
+        image_name = os.path.join(args.result_dir, f"mnist_result_{n_epoch:04d}.png")
+        torchvision.utils.save_image(
+            1 - results.reshape(-1, 1, 28, 28) / 255.0,
+            image_name,
+            nrow=16,
+            pad_value=0.8,
+        )
+        log_string(f"wrote {image_name}")
+
+
+######################################################################
+
+import maze
+
+
+class TaskMaze(Task):
+    def map2seq(self, *m):
+        return torch.cat([x.flatten(1) for x in m], 1)
+
+    def seq2map(self, s):
+        s = s.reshape(s.size(0), -1, self.height, self.width)
+        return (s[:, k] for k in range(s.size(1)))
+
+    def __init__(
+        self,
+        nb_train_samples,
+        nb_test_samples,
+        batch_size,
+        height,
+        width,
+        nb_walls,
+        device=torch.device("cpu"),
+    ):
+        self.batch_size = batch_size
+        self.height = height
+        self.width = width
+        self.device = device
+
+        train_mazes, train_paths, _ = maze.create_maze_data(
+            nb_train_samples,
+            height=height,
+            width=width,
+            nb_walls=nb_walls,
+            progress_bar=lambda x: tqdm.tqdm(x, dynamic_ncols=True, desc=f"data-train"),
+        )
+        self.train_input = self.map2seq(train_mazes.to(device), train_paths.to(device))
+
+        test_mazes, test_paths, _ = maze.create_maze_data(
+            nb_test_samples,
+            height=height,
+            width=width,
+            nb_walls=nb_walls,
+            progress_bar=lambda x: tqdm.tqdm(x, dynamic_ncols=True, desc=f"data-test"),
+        )
+        self.test_input = self.map2seq(test_mazes.to(device), test_paths.to(device))
+
+        self.nb_codes = max(self.train_input.max(), self.test_input.max()) + 1
+
+    def batches(self, split="train", nb_to_use=-1, desc=None):
+        assert split in {"train", "test"}
+        input = self.train_input if split == "train" else self.test_input
+        if nb_to_use > 0:
+            input = input[:nb_to_use]
+        if desc is None:
+            desc = f"epoch-{split}"
+        for batch in tqdm.tqdm(
+            input.split(self.batch_size), dynamic_ncols=True, desc=desc
+        ):
+            yield batch
+
+    def vocabulary_size(self):
+        return self.nb_codes
+
+    def compute_error(self, model, split="train", nb_to_use=-1):
+        nb_total, nb_correct = 0, 0
+        count = torch.zeros(
+            self.width * self.height,
+            self.width * self.height,
+            device=self.device,
+            dtype=torch.int64,
+        )
+        for input in tqdm.tqdm(
+            task.batches(split, nb_to_use),
+            dynamic_ncols=True,
+            desc=f"test-mazes",
+        ):
+            result = input.clone()
+            ar_mask = result.new_zeros(result.size())
+            ar_mask[:, self.height * self.width :] = 1
+            result *= 1 - ar_mask
+            masked_inplace_autoregression(
+                model,
+                self.batch_size,
+                result,
+                ar_mask,
+                progress_bar_desc=None,
+                device=self.device,
+            )
+            mazes, paths = self.seq2map(result)
+            path_correctness = maze.path_correctness(mazes, paths)
+            nb_correct += path_correctness.long().sum()
+            nb_total += mazes.size(0)
+
+            optimal_path_lengths = (
+                (input[:, self.height * self.width :] == maze.v_path).long().sum(1)
+            )
+            predicted_path_lengths = (
+                (result[:, self.height * self.width :] == maze.v_path).long().sum(1)
+            )
+            optimal_path_lengths = optimal_path_lengths[path_correctness]
+            predicted_path_lengths = predicted_path_lengths[path_correctness]
+            count[optimal_path_lengths, predicted_path_lengths] += 1
+
+        if count.max() == 0:
+            count = None
+        else:
+            count = count[
+                : count.sum(1).nonzero().max() + 1, : count.sum(0).nonzero().max() + 1
+            ]
+
+        return nb_total, nb_correct, count
+
+    def produce_results(self, n_epoch, model):
+        with torch.autograd.no_grad():
+            t = model.training
+            model.eval()
+
+            train_nb_total, train_nb_correct, count = self.compute_error(
+                model, "train", nb_to_use=1000
+            )
+            log_string(
+                f"accuracy_train {n_epoch} nb_total {train_nb_total} nb_correct {train_nb_correct} accuracy {(100.0*train_nb_correct)/train_nb_total:.02f}%"
+            )
 
-def pruner_horizontal_green(p):
+            test_nb_total, test_nb_correct, count = self.compute_error(
+                model, "test", nb_to_use=1000
+            )
+            log_string(
+                f"accuracy_test {n_epoch} nb_total {test_nb_total} nb_correct {test_nb_correct} accuracy {(100.0*test_nb_correct)/test_nb_total:.02f}%"
+            )
+
+            if count is not None:
+                proportion_optimal = count.diagonal().sum().float() / count.sum()
+                log_string(f"proportion_optimal_test {proportion_optimal*100:.02f}%")
+                with open(
+                    os.path.join(args.result_dir, f"maze_result_{n_epoch:04d}.txt"), "w"
+                ) as f:
+                    for i in range(count.size(0)):
+                        for j in range(count.size(1)):
+                            eol = " " if j < count.size(1) - 1 else "\n"
+                            f.write(f"{count[i,j]}{eol}")
+
+            input = self.test_input[:48]
+            result = input.clone()
+            ar_mask = result.new_zeros(result.size())
+            ar_mask[:, self.height * self.width :] = 1
+            result *= 1 - ar_mask
+            masked_inplace_autoregression(
+                model, self.batch_size, result, ar_mask, device=self.device
+            )
+
+            mazes, paths = self.seq2map(input)
+            _, predicted_paths = self.seq2map(result)
+
+            filename = os.path.join(args.result_dir, f"maze_result_{n_epoch:04d}.png")
+            maze.save_image(
+                filename,
+                mazes=mazes,
+                target_paths=paths,
+                predicted_paths=predicted_paths,
+                path_correct=maze.path_correctness(mazes, predicted_paths),
+                path_optimal=maze.path_optimality(paths, predicted_paths),
+            )
+            log_string(f"wrote {filename}")
+
+            model.train(t)
+
+
+######################################################################
+
+
+import snake
+
+
+class TaskSnake(Task):
+    def __init__(
+        self,
+        nb_train_samples,
+        nb_test_samples,
+        batch_size,
+        height,
+        width,
+        nb_colors,
+        length,
+        prompt_length,
+        device=torch.device("cpu"),
+    ):
+        self.batch_size = batch_size
+        self.height = height
+        self.width = width
+        self.device = device
+        self.prompt_length = prompt_length
+
+        self.train_input, self.train_prior_visits, _, _ = snake.generate_sequences(
+            nb_train_samples,
+            height,
+            width,
+            nb_colors,
+            length,
+            prompt_length,
+            self.device,
+        )
+        self.test_input, self.test_prior_visits, _, _ = snake.generate_sequences(
+            nb_test_samples,
+            height,
+            width,
+            nb_colors,
+            length,
+            prompt_length,
+            self.device,
+        )
+
+        self.nb_codes = max(self.train_input.max(), self.test_input.max()) + 1
+
+    def batches(self, split="train", nb_to_use=-1, desc=None):
+        assert split in {"train", "test"}
+        input = self.train_input if split == "train" else self.test_input
+        if nb_to_use > 0:
+            input = input[:nb_to_use]
+        if desc is None:
+            desc = f"epoch-{split}"
+        for batch in tqdm.tqdm(
+            input.split(self.batch_size), dynamic_ncols=True, desc=desc
+        ):
+            yield batch
+
+    def vocabulary_size(self):
+        return self.nb_codes
+
+    def produce_results(self, n_epoch, model):
+        with torch.autograd.no_grad():
+            t = model.training
+            model.eval()
+
+            def compute_nb_correct(input, prior_visits):
+                result = input.clone()
+                i = torch.arange(result.size(1), device=result.device)[None, :]
+                ar_mask = (
+                    torch.logical_and(i >= self.prompt_length * 2, i % 2 == 0)
+                    .long()
+                    .expand_as(result)
+                )
+                result *= 1 - ar_mask
+
+                # snake.solver(result,ar_mask)
+
+                masked_inplace_autoregression(
+                    model, self.batch_size, result, ar_mask, device=self.device
+                )
+
+                nb_total = ((prior_visits > 0) * ar_mask).sum()
+
+                nb_correct = (
+                    (result == input).long() * (prior_visits > 0) * ar_mask
+                ).sum()
+
+                # nb_total = result.size(0)
+                # nb_correct = ((result - input).abs().sum(1) == 0).sum()
+
+                return nb_total, nb_correct
+
+            # train_nb_total, train_nb_correct = compute_nb_correct(
+            # self.train_input, self.train_prior_visits
+            # )
+
+            # log_string(
+            # f"accuracy_train nb_total {train_nb_total} nb_correct {train_nb_correct} accuracy {(100.0*train_nb_correct)/train_nb_total:.02f}%"
+            # )
+
+            test_nb_total, test_nb_correct = compute_nb_correct(
+                self.test_input[:1000], self.test_prior_visits[:1000]
+            )
+
+            log_string(
+                f"accuracy_test {n_epoch} nb_total {test_nb_total} nb_correct {test_nb_correct} accuracy {(100.0*test_nb_correct)/test_nb_total:.02f}%"
+            )
+
+            model.train(t)
+
+
+######################################################################
+
+
+import stack
+
+
+class TaskStack(Task):
+    def __init__(
+        self,
+        nb_train_samples,
+        nb_test_samples,
+        batch_size,
+        nb_steps,
+        nb_stacks,
+        nb_digits,
+        fraction_values_for_train=None,
+        device=torch.device("cpu"),
+    ):
+        self.batch_size = batch_size
+        self.nb_steps = nb_steps
+        self.nb_stacks = nb_stacks
+        self.nb_digits = nb_digits
+        self.device = device
+
+        if fraction_values_for_train is None:
+            values_for_train = None
+            values_for_test = None
+        else:
+            all = torch.randperm(10**nb_digits)
+            nb_for_train = int(all.size(0) * fraction_values_for_train)
+            values_for_train = all[:nb_for_train]
+            values_for_test = all[nb_for_train:]
+
+        self.train_input, self.train_stack_counts = stack.generate_sequences(
+            nb_train_samples,
+            nb_steps,
+            nb_stacks,
+            nb_digits,
+            values_for_train,
+            self.device,
+        )
+
+        self.test_input, self.test_stack_counts = stack.generate_sequences(
+            nb_test_samples,
+            nb_steps,
+            nb_stacks,
+            nb_digits,
+            values_for_test,
+            self.device,
+        )
+
+        i = torch.logical_and(self.test_input % 2 == 1, self.test_input < 2 * nb_stacks)
+        counts = self.test_stack_counts.flatten()[i.flatten()]
+        counts = F.one_hot(counts).sum(0)
+        log_string(f"test_pop_stack_counts {counts}")
+
+        self.nb_codes = max(self.train_input.max(), self.test_input.max()) + 1
+
+    def batches(self, split="train", nb_to_use=-1, desc=None):
+        assert split in {"train", "test"}
+        input = self.train_input if split == "train" else self.test_input
+        if nb_to_use > 0:
+            input = input[:nb_to_use]
+        if desc is None:
+            desc = f"epoch-{split}"
+        for batch in tqdm.tqdm(
+            input.split(self.batch_size), dynamic_ncols=True, desc=desc
+        ):
+            yield batch
+
+    def vocabulary_size(self):
+        return self.nb_codes
+
+    def produce_results(self, n_epoch, model):
+        with torch.autograd.no_grad():
+            t = model.training
+            model.eval()
+
+            def compute_nb_correct(input):
+                result = input.clone()
+                stack.remove_popped_values(result, self.nb_stacks, self.nb_digits)
+                ar_mask = (result != input).long()
+                masked_inplace_autoregression(
+                    model, self.batch_size, result, ar_mask, device=self.device
+                )
+
+                errors = ((result != input).long() * ar_mask).reshape(
+                    -1, 1 + self.nb_digits
+                )
+                ar_mask = ar_mask.reshape(-1, 1 + self.nb_digits)
+
+                nb_total = ar_mask.max(1).values.sum()
+                nb_correct = nb_total - errors.max(1).values.sum()
+
+                return nb_total, nb_correct
+
+            test_nb_total, test_nb_correct = compute_nb_correct(self.test_input[:1000])
+
+            log_string(
+                f"accuracy_test {n_epoch} nb_total {test_nb_total} nb_correct {test_nb_correct} accuracy {(100.0*test_nb_correct)/test_nb_total:.02f}%"
+            )
+
+            ##############################################################
+            # Log a few generated sequences
+            input = self.test_input[:10, : 12 * (1 + self.nb_digits)]
+            result = input.clone()
+            stack.remove_popped_values(result, self.nb_stacks, self.nb_digits)
+            ar_mask = (result != input).long()
+            for n in range(result.size(0)):
+                log_string(
+                    f"test_before {stack.seq_to_str(result[n],nb_stacks=self.nb_stacks,nb_digits=self.nb_digits)}"
+                )
+            masked_inplace_autoregression(
+                model, self.batch_size, result, ar_mask, device=self.device
+            )
+            for n in range(result.size(0)):
+                log_string(
+                    f"test_after  {stack.seq_to_str(result[n],nb_stacks=self.nb_stacks,nb_digits=self.nb_digits)}"
+                )
+            ##############################################################
+
+            model.train(t)
+
+
+######################################################################
+
+
+import expr
+
+
+class TaskExpr(Task):
+    def __init__(
+        self,
+        nb_train_samples,
+        nb_test_samples,
+        nb_variables,
+        sequence_length,
+        batch_size,
+        device=torch.device("cpu"),
+    ):
+        self.batch_size = batch_size
+        self.device = device
+
+        train_sequences = expr.generate_sequences(
+            nb_train_samples,
+            nb_variables=nb_variables,
+            length=sequence_length,
+            # length=2 * sequence_length,
+            # randomize_length=True,
+        )
+        test_sequences = expr.generate_sequences(
+            nb_test_samples,
+            nb_variables=nb_variables,
+            length=sequence_length,
+        )
+        self.char2id = dict(
+            [
+                (c, n)
+                for n, c in enumerate(
+                    set("#" + "".join(train_sequences + test_sequences))
+                )
+            ]
+        )
+        self.id2char = dict([(n, c) for c, n in self.char2id.items()])
+
+        self.filler, self.space = self.char2id["#"], self.char2id[" "]
+
+        len_max = max([len(x) for x in train_sequences])
+        self.train_input = torch.cat(
+            [
+                torch.tensor(
+                    [
+                        [self.char2id[c] for c in s + "#" * (len_max - len(s))]
+                        for s in train_sequences
+                    ]
+                )
+            ],
+            0,
+        ).to(device)
+
+        len_max = max([len(x) for x in test_sequences])
+        self.test_input = torch.cat(
+            [
+                torch.tensor(
+                    [
+                        [self.char2id[c] for c in s + "#" * (len_max - len(s))]
+                        for s in test_sequences
+                    ]
+                )
+            ],
+            0,
+        ).to(device)
+
+        self.nb_codes = max(self.train_input.max(), self.test_input.max()) + 1
+
+    def batches(self, split="train", nb_to_use=-1, desc=None):
+        assert split in {"train", "test"}
+        input = self.train_input if split == "train" else self.test_input
+        if nb_to_use > 0:
+            input = input[:nb_to_use]
+        if desc is None:
+            desc = f"epoch-{split}"
+        for batch in tqdm.tqdm(
+            input.split(self.batch_size), dynamic_ncols=True, desc=desc
+        ):
+            if split == "train":
+                last = (batch != self.filler).max(0).values.nonzero().max() + 1
+                batch = batch[:, :last]
+            yield batch
+
+    def vocabulary_size(self):
+        return self.nb_codes
+
+    def seq2str(self, s):
+        return "".join([self.id2char[k.item()] for k in s])
+
+    def produce_results(self, n_epoch, model):
+        with torch.autograd.no_grad():
+            t = model.training
+            model.eval()
+
+            def compute_nb_correct(input):
+                result = input.clone()
+                ar_mask = (result == self.space).long().cumsum(dim=1).clamp(max=1)
+                result = (1 - ar_mask) * result + ar_mask * self.filler
+                masked_inplace_autoregression(
+                    model, self.batch_size, result, ar_mask, device=self.device
+                )
+
+                nb_total = input.size(0)
+                nb_correct = (input == result).long().min(1).values.sum()
+
+                #######################################################################
+                # Comput predicted vs. true variable values
+
+                nb_delta = torch.zeros(5, dtype=torch.int64)
+                nb_missed = 0
+
+                values_input = expr.extract_results([self.seq2str(s) for s in input])
+                values_result = expr.extract_results([self.seq2str(s) for s in result])
+
+                for i, r in zip(values_input, values_result):
+                    for n, vi in i.items():
+                        vr = r.get(n)
+                        if vr is None or vr < 0:
+                            nb_missed += 1
+                        else:
+                            d = abs(vr - vi)
+                            if d >= nb_delta.size(0):
+                                nb_missed += 1
+                            else:
+                                nb_delta[d] += 1
+
+                ######################################################################
+
+                return nb_total, nb_correct, nb_delta, nb_missed
+
+            (
+                test_nb_total,
+                test_nb_correct,
+                test_nb_delta,
+                test_nb_missed,
+            ) = compute_nb_correct(self.test_input[:1000])
+
+            log_string(
+                f"accuracy_test {n_epoch} nb_total {test_nb_total} nb_correct {test_nb_correct} accuracy {(100.0*test_nb_correct)/test_nb_total:.02f}%"
+            )
+
+            nb_total = test_nb_delta.sum() + test_nb_missed
+            for d in range(test_nb_delta.size(0)):
+                log_string(
+                    f"error_value {n_epoch} delta {d} {test_nb_delta[d]} {test_nb_delta[d]*100/nb_total:.02f}%"
+                )
+            log_string(
+                f"error_value {n_epoch} missed {test_nb_missed} {test_nb_missed*100/nb_total:.02f}%"
+            )
+
+            ##############################################################
+            # Log a few generated sequences
+            input = self.test_input[:10]
+            result = input.clone()
+            ar_mask = (result == self.space).long().cumsum(dim=1).clamp(max=1)
+            result = (1 - ar_mask) * result + ar_mask * self.filler
+            for n in range(result.size(0)):
+                log_string(f"test_before {self.seq2str(result[n])}")
+            masked_inplace_autoregression(
+                model, self.batch_size, result, ar_mask, device=self.device
+            )
+            correct = (1 - ar_mask) * self.space + ar_mask * input
+            for n in range(result.size(0)):
+                comment = "GOOD" if (result[n] - input[n]).abs().max() == 0 else ""
+                log_string(f"test_after  {self.seq2str(result[n])} {comment}")
+                log_string(f"correct     {self.seq2str(correct[n])}")
+            ##############################################################
+
+            model.train(t)
+
+
+######################################################################
+
+
+def picoclvr_pruner_horizontal_green(p):
     return not ("green" in p and ("left" in p or "right" in p))
 
 
-task = TaskPicoCLVR(
-    batch_size=args.batch_size,
-    height=args.height,
-    width=args.width,
-    nb_colors=args.nb_colors,
-    device=device,
-    pruner_train=pruner_horizontal_green
-    if args.prune_properties in {"train+eval"}
-    else None,
-    pruner_eval=(lambda p: not pruner_horizontal_green(p))
-    if args.prune_properties in {"train+eval", "eval"}
-    else None,
+picoclvr_pruner_train = (
+    picoclvr_pruner_horizontal_green
+    if args.picocvlr_prune_properties in {"train+eval"}
+    else None
 )
 
+picoclvr_pruner_eval = (
+    (lambda p: not picoclvr_pruner_horizontal_green(p))
+    if args.picocvlr_prune_properties in {"train+eval", "eval"}
+    else None
+)
+
+######################################################################
+
+if args.task == "picoclvr":
+    task = TaskPicoCLVR(
+        nb_train_samples=args.nb_train_samples,
+        nb_test_samples=args.nb_test_samples,
+        batch_size=args.batch_size,
+        height=args.picoclvr_height,
+        width=args.picoclvr_width,
+        nb_colors=args.picoclvr_nb_colors,
+        device=device,
+        pruner_train=picoclvr_pruner_train,
+        pruner_eval=picoclvr_pruner_eval,
+    )
+
+elif args.task == "mnist":
+    task = TaskMNIST(
+        batch_size=args.batch_size,
+        device=device,
+    )
+
+elif args.task == "maze":
+    task = TaskMaze(
+        nb_train_samples=args.nb_train_samples,
+        nb_test_samples=args.nb_test_samples,
+        batch_size=args.batch_size,
+        height=args.maze_height,
+        width=args.maze_width,
+        nb_walls=args.maze_nb_walls,
+        device=device,
+    )
+
+elif args.task == "snake":
+    task = TaskSnake(
+        nb_train_samples=args.nb_train_samples,
+        nb_test_samples=args.nb_test_samples,
+        batch_size=args.batch_size,
+        height=args.snake_height,
+        width=args.snake_width,
+        nb_colors=args.snake_nb_colors,
+        length=args.snake_length,
+        prompt_length=args.snake_length // 2,
+        device=device,
+    )
+
+elif args.task == "stack":
+    task = TaskStack(
+        nb_train_samples=args.nb_train_samples,
+        nb_test_samples=args.nb_test_samples,
+        batch_size=args.batch_size,
+        nb_steps=args.stack_nb_steps,
+        nb_stacks=args.stack_nb_stacks,
+        nb_digits=args.stack_nb_digits,
+        fraction_values_for_train=args.stack_fraction_values_for_train,
+        device=device,
+    )
+
+elif args.task == "expr":
+    task = TaskExpr(
+        nb_train_samples=args.nb_train_samples,
+        nb_test_samples=args.nb_test_samples,
+        nb_variables=args.expr_nb_variables,
+        sequence_length=args.expr_sequence_length,
+        batch_size=args.batch_size,
+        device=device,
+    )
+
+else:
+    raise ValueError(f"Unknown task {args.task}")
+
+######################################################################
+
+log_string(f"device {device}")
+
 vocabulary_size = task.vocabulary_size()
 
 log_string(f"vocabulary_size {vocabulary_size}")
@@ -561,7 +1366,6 @@ if nb_epochs_finished >= nb_epochs:
     task.produce_results(nb_epochs_finished, model)
 
 for n_epoch in range(nb_epochs_finished, nb_epochs):
-
     learning_rate = learning_rate_schedule[n_epoch]
 
     log_string(f"learning_rate {learning_rate}")
@@ -592,7 +1396,6 @@ for n_epoch in range(nb_epochs_finished, nb_epochs):
         optimizer.step()
 
     with torch.autograd.no_grad():
-
         model.eval()
 
         nb_test_samples, acc_test_loss = 0, 0.0
@@ -600,9 +1403,6 @@ for n_epoch in range(nb_epochs_finished, nb_epochs):
         for input in task.batches(split="test"):
             input = input.to(device)
 
-            # input, loss_masks, true_images = task.excise_last_image(input)
-            # input, loss_masks = task.add_true_image(input, true_images, loss_masks)
-
             output = model(mygpt.BracketedSequence(input)).x
             loss = F.cross_entropy(output.transpose(1, 2), input)
             acc_test_loss += loss.item() * input.size(0)