train.py

import argparse
import time
import yaml

import torch
from torch import nn
from transformer import TransformerModel
from bar_distribution import BarDistribution, FullSupportBarDistribution, get_bucket_limits
from utils import get_cosine_schedule_with_warmup, get_openai_lr, StoreDictKeyPair, get_weighted_single_eval_pos_sampler, get_uniform_single_eval_pos_sampler
import priors
import encoders
import positional_encodings

class Losses():
    gaussian = nn.GaussianNLLLoss(full=True, reduction='none')
    mse = nn.MSELoss(reduction='none')
    ce = nn.CrossEntropyLoss(reduction='none')
    bce = nn.BCEWithLogitsLoss(reduction='none')
    get_BarDistribution = BarDistribution


def train(priordataloader_class, criterion, encoder_generator, emsize=200, nhid=200, nlayers=6, nhead=2, dropout=0.2,
          epochs=10, steps_per_epoch=100, batch_size=200, bptt=10, lr=None, warmup_epochs=10, input_normalization=False,
          y_encoder_generator=None, pos_encoder_generator=None, decoder=None, extra_prior_kwargs_dict={}, scheduler=get_cosine_schedule_with_warmup,
          load_weights_from_this_state_dict=None, validation_period=10, single_eval_pos_gen=None, gpu_device='cuda:0',
          aggregate_k_gradients=1, verbose=True
          ):

    device = gpu_device if torch.cuda.is_available() else 'cpu:0'
    print(f'Using {device} device')
    dl = priordataloader_class(num_steps=steps_per_epoch, batch_size=batch_size, seq_len=bptt, **extra_prior_kwargs_dict)

    encoder = encoder_generator(dl.num_features+1 if dl.fuse_x_y else dl.num_features,emsize)
    n_out = dl.num_outputs
    if isinstance(criterion, nn.GaussianNLLLoss):
        n_out *= 2
    elif isinstance(criterion, BarDistribution) or "BarDistribution" in criterion.__class__.__name__: # TODO remove this fix (only for dev)
        assert n_out == 1
        n_out = criterion.num_bars
    model = TransformerModel(encoder, n_out, emsize, nhead, nhid, nlayers, dropout,
                             y_encoder=y_encoder_generator(1, emsize), input_normalization=input_normalization,
                             pos_encoder=(pos_encoder_generator or positional_encodings.NoPositionalEncoding)(emsize, bptt*2),
                             decoder=decoder
                             )
    model.criterion = criterion
    if load_weights_from_this_state_dict is not None:
        model.load_state_dict(load_weights_from_this_state_dict)
    model.to(device)


    # learning rate
    if lr is None:
        lr = get_openai_lr(model)
        print(f"Using OpenAI max lr of {lr}.")
    optimizer = torch.optim.Adam(model.parameters(), lr=lr)
    scheduler = scheduler(optimizer, warmup_epochs, epochs)

    def train():
        model.train()  # Turn on the train mode
        total_loss = 0.
        total_positional_losses = 0.
        total_positional_losses_recorded = 0
        start_time = time.time()
        before_get_batch = time.time()
        assert len(dl) % aggregate_k_gradients == 0, 'Please set the number of steps per epoch s.t. `aggregate_k_gradients` divides it.'
        for batch, (data, targets) in enumerate(dl):
            time_to_get_batch = time.time() - before_get_batch
            before_forward = time.time()
            single_eval_pos = single_eval_pos_gen() if callable(single_eval_pos_gen) else single_eval_pos_gen
            output = model(tuple(e.to(device) for e in data) if isinstance(data, tuple) else data.to(device)
                           , single_eval_pos=single_eval_pos)

            forward_time = time.time() - before_forward

            if single_eval_pos is not None:
                targets = targets[single_eval_pos:]

            if isinstance(criterion, nn.GaussianNLLLoss):
                assert output.shape[-1] == 2, \
                    'need to write a little bit of code to handle multiple regression targets at once'

                mean_pred = output[..., 0]
                var_pred = output[..., 1].abs()
                losses = criterion(mean_pred.flatten(), targets.to(device).flatten(), var=var_pred.flatten())
            elif isinstance(criterion, (nn.MSELoss, nn.BCEWithLogitsLoss)):
                losses = criterion(output.flatten(), targets.to(device).flatten())
            else:
                losses = criterion(output.reshape(-1, n_out), targets.to(device).flatten())
            losses = losses.view(*output.shape[0:2]).squeeze(-1)


            loss = losses.mean()
            loss.backward()
            if batch % aggregate_k_gradients == aggregate_k_gradients - 1:
                torch.nn.utils.clip_grad_norm_(model.parameters(), 1.)
                optimizer.step()
                optimizer.zero_grad()

            step_time = time.time() - before_forward

            total_loss += loss.item()
            total_positional_losses += losses.mean(1).cpu().detach() if single_eval_pos is None else \
                nn.functional.one_hot(torch.tensor(single_eval_pos), bptt)*loss.cpu().detach()

            total_positional_losses_recorded += torch.ones(bptt) if single_eval_pos is None else \
                nn.functional.one_hot(torch.tensor(single_eval_pos), bptt)

            before_get_batch = time.time()
        return total_loss / steps_per_epoch, (
                    total_positional_losses / total_positional_losses_recorded).tolist(), time_to_get_batch, forward_time, step_time

    best_val_loss = float("inf")
    best_model = None
    total_loss = float('inf')
    total_positional_losses = float('inf')
    for epoch in range(1, epochs + 1):
        epoch_start_time = time.time()
        total_loss, total_positional_losses, time_to_get_batch, forward_time, step_time = train()
        if hasattr(dl, 'validate') and epoch % validation_period == 0:
            with torch.no_grad():
                val_score = dl.validate(model)
        else:
            val_score = None

        if verbose:
            print('-' * 89)
            print(
                f'| end of epoch {epoch:3d} | time: {(time.time() - epoch_start_time):5.2f}s | mean loss {total_loss:5.2f} | '
                f"pos losses {','.join([f'{l:5.2f}' for l in total_positional_losses])}, lr {scheduler.get_last_lr()[0]}"
                f' data time {time_to_get_batch:5.2f} step time {step_time:5.2f}'
                f' forward time {forward_time:5.2f}' + (f'val score {val_score}' if val_score is not None else ''))
            print('-' * 89)

        scheduler.step()
    return total_loss, total_positional_losses, model.to('cpu')

def _parse_args(config_parser, parser):
    # Do we have a config file to parse?
    args_config, remaining = config_parser.parse_known_args()
    if args_config.config:
        with open(args_config.config, 'r') as f:
            cfg = yaml.safe_load(f)
            parser.set_defaults(**cfg)

    # The main arg parser parses the rest of the args, the usual
    # defaults will have been overridden if config file specified.
    args = parser.parse_args(remaining)

    # Cache the args as a text string to save them in the output dir later
    args_text = yaml.safe_dump(args.__dict__, default_flow_style=False)
    return args, args_text


if __name__ == '__main__':
    config_parser = argparse.ArgumentParser(description='Only used as a first parser for the config file path.')
    config_parser.add_argument('--config')
    parser = argparse.ArgumentParser()
    parser.add_argument('prior')
    parser.add_argument('--loss_function', default='barnll')
    # Optional Arg's for `--loss_function barnll`
    parser.add_argument('--min_y', type=float, help='barnll can only model y in strict ranges, this is the minimum y can take.')
    parser.add_argument('--max_y', type=float, help='barnll can only model y in strict ranges, this is the maximum y can take.')
    parser.add_argument('--num_buckets', default=100, type=int)
    #parser.add_argument('--num_features', default=None, type=int, help='Specify depending on the prior.')
    parser.add_argument("--extra_prior_kwargs_dict", default={'fuse_x_y': False}, dest="extra_prior_kwargs_dict", action=StoreDictKeyPair, nargs="+", metavar="KEY=VAL", help='Specify depending on the prior.')
    parser.add_argument('--encoder', default='linear', type=str, help='Specify depending on the prior.')
    parser.add_argument('--y_encoder', default='linear', type=str, help='Specify depending on the prior. You should specify this if you do not fuse x and y.')
    parser.add_argument('--pos_encoder', default='sinus', type=str, help='Specify depending on the prior.')
    parser.add_argument('--bptt', default=10, type=int)
    parser.add_argument('--epochs', default=200, type=int)
    parser.add_argument('--warmup_epochs', default=50, type=int)
    parser.add_argument('--validation_period', default=10, type=int)
    parser.add_argument('--permutation_invariant_max_eval_pos', default=None, type=int, help='Set this to an int to ')
    parser.add_argument('--permutation_invariant_sampling', default='weighted', help="Only relevant if --permutation_invariant_max_eval_pos is set.")

    # these can likely be mostly left at defaults
    parser.add_argument('--emsize', default=512, type=int) # sometimes even larger is better e.g. 1024
    parser.add_argument('--nlayers', default=6, type=int)
    parser.add_argument('--nhid', default=None, type=int) # 2*emsize is the default
    parser.add_argument('--nhead', default=4, type=int) # nhead = emsize / 64 in the original paper
    parser.add_argument('--dropout', default=.0, type=float)
    parser.add_argument('--steps_per_epoch', default=10, type=int)
    parser.add_argument('--batch_size', default=1000, type=int)
    parser.add_argument('--lr', '--learning_rate', default=.001, type=float) # try also .0003, .0001, go lower with lower batch size

    args, _ = _parse_args(config_parser, parser)

    if args.nhid is None:
        args.nhid = 2*args.emsize

    prior = args.__dict__.pop('prior')

    if prior == 'gp':
        prior = priors.fast_gp.DataLoader
    elif prior == 'ridge':
        prior = priors.ridge.DataLoader
    elif prior == 'stroke':
        prior = priors.stroke.DataLoader
    elif prior == 'mix_gp':
        prior = priors.fast_gp_mix.DataLoader
    else:
        raise NotImplementedError(f'Prior == {prior}.')


    loss_function = args.__dict__.pop('loss_function')

    criterion = nn.GaussianNLLLoss(reduction='none', full=True)
    classificiation_criterion = nn.CrossEntropyLoss(reduction='none')
    num_buckets = args.__dict__.pop('num_buckets')
    max_y = args.__dict__.pop('max_y')
    min_y = args.__dict__.pop('min_y')
    # criterion = nn.MSELoss(reduction='none')

    def get_y_sample():
        dl = prior(num_steps=1, batch_size=args.batch_size * args.steps_per_epoch, seq_len=args.bptt,
                   **args.extra_prior_kwargs_dict)
        y_sample = next(iter(dl))[-1]
        print(f'Creating Bar distribution with borders from y sample of size {y_sample.numel()}')
        return y_sample

    if loss_function == 'ce':
        criterion = nn.CrossEntropyLoss(reduction='none')
    elif loss_function == 'gaussnll':
        criterion = nn.GaussianNLLLoss(reduction='none', full=True)
    elif loss_function == 'mse':
        criterion = nn.MSELoss(reduction='none')
    elif loss_function == 'barnll':
        criterion = BarDistribution(borders=get_bucket_limits(num_buckets, full_range=(min_y,max_y)))
    elif loss_function == 'adaptivebarnll':
        borders = get_bucket_limits(num_buckets, ys=get_y_sample(), full_range=(min_y,max_y))
        criterion = BarDistribution(borders=borders)
    elif loss_function == 'adaptivefullsupportbarnll':
        assert min_y is None and max_y is None, "Please do not specify `min_y` and `max_y` with `unboundedadaptivebarnll`."
        borders = get_bucket_limits(num_buckets, ys=get_y_sample())
        criterion = FullSupportBarDistribution(borders=borders)
    else:
        raise NotImplementedError(f'loss_function == {loss_function}.')



    encoder = args.__dict__.pop('encoder')
    y_encoder = args.__dict__.pop('y_encoder')

    def get_encoder_generator(encoder):
        if encoder == 'linear':
            encoder_generator = encoders.Linear
        elif encoder == 'mlp':
            encoder_generator = encoders.MLP
        elif encoder == 'positional':
            encoder_generator = encoders.Positional
        else:
            raise NotImplementedError(f'A {encoder} encoder is not valid.')
        return encoder_generator

    encoder_generator = get_encoder_generator(encoder)
    y_encoder_generator = get_encoder_generator(y_encoder)

    pos_encoder = args.__dict__.pop('pos_encoder')

    if pos_encoder == 'none':
        pos_encoder_generator = None
    elif pos_encoder == 'sinus':
        pos_encoder_generator = positional_encodings.PositionalEncoding
    elif pos_encoder == 'learned':
        pos_encoder_generator = positional_encodings.LearnedPositionalEncoding
    elif pos_encoder == 'paired_scrambled_learned':
        pos_encoder_generator = positional_encodings.PairedScrambledPositionalEncodings
    else:
        raise NotImplementedError(f'pos_encoer == {pos_encoder} is not valid.')

    permutation_invariant_max_eval_pos = args.__dict__.pop('permutation_invariant_max_eval_pos')
    permutation_invariant_sampling = args.__dict__.pop('permutation_invariant_sampling')
    if permutation_invariant_max_eval_pos is not None:
        if permutation_invariant_sampling == 'weighted':
            get_sampler = get_weighted_single_eval_pos_sampler
        elif permutation_invariant_sampling == 'uniform':
            get_sampler = get_uniform_single_eval_pos_sampler
        else:
            raise ValueError()
        args.__dict__['single_eval_pos_gen'] = get_sampler(permutation_invariant_max_eval_pos)


    print("ARGS for `train`:", args.__dict__)

    train(prior, criterion, encoder_generator,
          y_encoder_generator=y_encoder_generator,pos_encoder_generator=pos_encoder_generator,
          **args.__dict__)