train.py

import os, pickle, numpy as np, pandas as pd, torch, torch.nn as nn
from datasets import load_dataset
from transformers import AutoModelForSeq2SeqLM, AutoConfig, TrainingArguments, Trainer, EarlyStoppingCallback, set_seed
from peft import LoraConfig, get_peft_model, TaskType
import trackio
from sklearn.preprocessing import StandardScaler, LabelEncoder

SEED=42; MODEL_NAME='amazon/chronos-bolt-small'; OUTPUT_DIR='/tmp/outputs'
HUB_MODEL_ID='superdkj/retail-world-model-v1'; DATASET_NAME='t4tiana/store-sales-time-series-forecasting'
CONTEXT_LENGTH=60; PREDICTION_LENGTH=14; NUM_VARIATES=5; EMBED_DIM=64
set_seed(SEED)
trackio.init(project='retail-world-model', run_name='retail-world-model-v1')

class RetailWorldModel(nn.Module):
    def __init__(self, base_model_name, context_len, pred_len, num_variates, embed_dim):
        super().__init__()
        self.config = AutoConfig.from_pretrained(base_model_name)
        self.encoder = AutoModelForSeq2SeqLM.from_pretrained(base_model_name)
        self.context_len=context_len; self.pred_len=pred_len
        self.num_variates=num_variates; self.embed_dim=embed_dim
        self.input_proj = nn.Linear(num_variates, self.config.d_model)
        self.latent_dynamics = nn.LSTM(self.config.d_model, self.config.d_model, 2, batch_first=True, dropout=0.1)
        self.mean_head = nn.Sequential(nn.Linear(self.config.d_model, embed_dim), nn.GELU(), nn.Linear(embed_dim, 1))
        self.var_head = nn.Sequential(nn.Linear(self.config.d_model, embed_dim), nn.GELU(), nn.Linear(embed_dim, 1), nn.Softplus())
    def forward(self, context, target=None, return_loss=True):
        x = self.input_proj(context)
        enc_out = self.encoder.encoder(inputs_embeds=x, return_dict=True).last_hidden_state
        h0 = enc_out[:, -1:, :].transpose(0, 1).repeat(2, 1, 1)
        c0 = torch.zeros_like(h0)
        states=[]; curr = enc_out[:, -1:, :]
        for _ in range(self.pred_len):
            out, (h0, c0) = self.latent_dynamics(curr, (h0, c0))
            states.append(out); curr=out
        states = torch.cat(states, dim=1)
        mean = self.mean_head(states).squeeze(-1)
        var = self.var_head(states).squeeze(-1)
        if return_loss and target is not None:
            loss = torch.mean(0.5 * torch.log(var+1e-6) + 0.5 * (target-mean)**2 / (var+1e-6))
            return {'loss': loss, 'mean': mean, 'var': var}
        return {'mean': mean, 'var': var}

class RetailDataset(torch.utils.data.Dataset):
    def __init__(self, df, context_len=60, pred_len=14, scaler=None, fit_scaler=False):
        self.context_len=context_len; self.pred_len=pred_len
        df = df.copy()
        df['date'] = pd.to_datetime(df['date'])
        df['day_of_week'] = df['date'].dt.dayofweek / 6.0
        df['month'] = df['date'].dt.month / 12.0
        self.family_enc = LabelEncoder()
        df['family_enc'] = self.family_enc.fit_transform(df['family'])
        df['family_enc'] = df['family_enc'] / len(self.family_enc.classes_)
        self.groups=[]
        for _, g in df.groupby(['store_nbr', 'family']):
            g = g.sort_values('date').reset_index(drop=True)
            if len(g) >= context_len + pred_len: self.groups.append(g)
        if scaler is None:
            all_sales = np.concatenate([g['sales'].values for g in self.groups])
            self.scaler = StandardScaler()
            self.scaler.fit(all_sales.reshape(-1, 1))
        else: self.scaler = scaler
        for i, g in enumerate(self.groups):
            g = g.copy()
            g['sales_scaled'] = self.scaler.transform(g['sales'].values.reshape(-1, 1)).flatten()
            self.groups[i] = g
        self.windows=[]
        for g in self.groups:
            for start in range(0, len(g) - context_len - pred_len + 1, 7):
                end_ctx = start + context_len
                end_pred = end_ctx + pred_len
                ctx = g.iloc[start:end_ctx][['sales_scaled','onpromotion','day_of_week','month','family_enc']].values.astype(np.float32)
                tgt = g.iloc[end_ctx:end_pred]['sales_scaled'].values.astype(np.float32)
                self.windows.append((ctx, tgt))
    def __len__(self): return len(self.windows)
    def __getitem__(self, idx):
        ctx, tgt = self.windows[idx]
        return {'context': torch.tensor(ctx), 'target': torch.tensor(tgt)}

def collate_fn(batch):
    return {'context': torch.stack([b['context'] for b in batch]), 'target': torch.stack([b['target'] for b in batch])}

class RetailTrainer(Trainer):
    def compute_loss(self, model, inputs, return_outputs=False, **kwargs):
        out = model(inputs['context'], inputs['target'], return_loss=True)
        loss = out['loss']
        if return_outputs: return loss, out
        return loss
    def prediction_step(self, model, inputs, prediction_loss_only, ignore_keys=None):
        with torch.no_grad(): out = model(inputs['context'], inputs['target'], return_loss=True)
        loss = out['loss']
        if prediction_loss_only: return (loss, None, None)
        return (loss, out['mean'], inputs['target'])

print('Loading dataset...')
ds = load_dataset(DATASET_NAME, split='train')
df = ds.to_pandas()
print(f'Rows: {len(df)}, Stores: {df[\"store_nbr\"].nunique()}, Families: {df[\"family\"].nunique()}')
df['date'] = pd.to_datetime(df['date'])
split_date = df['date'].max() - pd.Timedelta(days=90)
train_df = df[df['date'] <= split_date]
val_df = df[df['date'] > split_date]
print(f'Train: {len(train_df)}, Val: {len(val_df)}')

print('Building datasets...')
train_ds = RetailDataset(train_df, CONTEXT_LENGTH, PREDICTION_LENGTH, fit_scaler=True)
val_ds = RetailDataset(val_df, CONTEXT_LENGTH, PREDICTION_LENGTH, scaler=train_ds.scaler, fit_scaler=False)
print(f'Train windows: {len(train_ds)}, Val windows: {len(val_ds)}')

os.makedirs(OUTPUT_DIR, exist_ok=True)
with open(f'{OUTPUT_DIR}/scaler.pkl', 'wb') as f: pickle.dump(train_ds.scaler, f)

print('Initializing model...')
model = RetailWorldModel(MODEL_NAME, CONTEXT_LENGTH, PREDICTION_LENGTH, NUM_VARIATES, EMBED_DIM)
lora_cfg = LoraConfig(r=16, lora_alpha=32, target_modules=['q','v','k','o'], lora_dropout=0.05, bias='none', task_type=TaskType.SEQ_2_SEQ_LM)
model.encoder = get_peft_model(model.encoder, lora_cfg)
model.encoder.print_trainable_parameters()

args = TrainingArguments(
    output_dir=OUTPUT_DIR, num_train_epochs=10, per_device_train_batch_size=32,
    per_device_eval_batch_size=64, learning_rate=1e-4, weight_decay=0.01,
    warmup_ratio=0.1, lr_scheduler_type='cosine', evaluation_strategy='epoch',
    save_strategy='epoch', logging_strategy='steps', logging_steps=50,
    logging_first_step=True, disable_tqdm=True, load_best_model_at_end=True,
    metric_for_best_model='eval_loss', greater_is_better=False,
    push_to_hub=True, hub_model_id=HUB_MODEL_ID, hub_strategy='every_save',
    save_total_limit=2, report_to='trackio', run_name='retail-world-model-v1',
    seed=SEED, dataloader_num_workers=4, gradient_accumulation_steps=2, fp16=True,
)

trainer = RetailTrainer(
    model=model, args=args, train_dataset=train_ds, eval_dataset=val_ds,
    data_collator=collate_fn, callbacks=[EarlyStoppingCallback(early_stopping_patience=3)],
)

print('Training...')
trainer.train()
trainer.save_model(f'{OUTPUT_DIR}/final')
eval_results = trainer.evaluate()
print(f'Final eval_loss: {eval_results[\"eval_loss\"]:.4f}')
trackio.alert(title='Training Complete', text=f'Final eval_loss={eval_results[\"eval_loss\"]:.4f}', level='INFO')
trainer.push_to_hub()
print('Done!')