File size: 6,767 Bytes
bf8df4f
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
import json
import os
from datetime import datetime
import torch
import torch.optim as optim
import os
import json
from datetime import datetime
import torch
from sklearn.metrics import (
    accuracy_score, precision_score, recall_score,
    f1_score, roc_auc_score
)


def evaluate_metrics(model, dataloader, device, threshold=0.5):
    """Run model on a dataloader and compute classification metrics."""
    model.eval()
    all_logits = []
    all_targets = []

    with torch.no_grad():
        for batch in dataloader:
            x_batch, y_batch = batch[0].to(device), batch[1].to(device)
            logits = model(x_batch)
            all_logits.append(logits.cpu())
            all_targets.append(y_batch.cpu())

    logits = torch.cat(all_logits)
    targets = torch.cat(all_targets)

    probs = torch.sigmoid(logits).numpy()
    preds = (probs > threshold).astype(int)
    targets_np = targets.numpy().astype(int)

    # average='macro' works for both binary and multi-label;
    # switch to 'binary' if you have a single output column and want binary-specific behavior
    avg = "macro" if targets_np.ndim > 1 and targets_np.shape[1] > 1 else "binary"

    metrics = {
        "accuracy": float(accuracy_score(targets_np, preds)),
        "precision": float(precision_score(targets_np, preds, average=avg, zero_division=0)),
        "recall": float(recall_score(targets_np, preds, average=avg, zero_division=0)),
        "f1": float(f1_score(targets_np, preds, average=avg, zero_division=0)),
    }


    return metrics


def train_mlp(model, train_loader, optimizer, criterion, num_epochs=300,
              save_dir="checkpoints", device="cpu", patience=20,
              val_loader=None):
    os.makedirs(save_dir, exist_ok=True)

    hyperparams = {
        "num_epochs": num_epochs,
        "learning_rate": optimizer.param_groups[0]["lr"],
        "optimizer": optimizer.__class__.__name__,
        "criterion": criterion.__class__.__name__,
        "batch_size": train_loader.batch_size,
        "model_class": model.__class__.__name__,
        "device": str(device),
        "patience": patience,
        "timestamp": datetime.now().isoformat(),
    }

    train_loss_history = []
    val_loss_history = []
    best_loss = float("inf")
    epochs_without_improvement = 0

    model.to(device)

    for epoch in range(num_epochs):
        # ---------- Training phase ----------
        model.train()
        total_loss = 0.0

        for batch in train_loader:
            x_batch, y_batch = batch[0].to(device), batch[1].to(device)

            optimizer.zero_grad()
            logits = model(x_batch)
            loss = criterion(logits, y_batch)
            loss.backward()
            optimizer.step()

            total_loss += loss.item()

        avg_train_loss = total_loss / len(train_loader)
        train_loss_history.append(avg_train_loss)

        # ---------- Validation phase ----------
        avg_val_loss = None
        if val_loader is not None:
            model.eval()
            val_loss = 0.0
            with torch.no_grad():
                for batch in val_loader:
                    x_batch, y_batch = batch[0].to(device), batch[1].to(device)
                    logits = model(x_batch)
                    val_loss += criterion(logits, y_batch).item()
            avg_val_loss = val_loss / len(val_loader)
            val_loss_history.append(avg_val_loss)

        # ---------- Checkpointing ----------
        monitor_loss = avg_val_loss if avg_val_loss is not None else avg_train_loss

        if monitor_loss < best_loss:
            best_loss = monitor_loss
            epochs_without_improvement = 0
            torch.save({
                "epoch": epoch + 1,
                "model_state_dict": model.state_dict(),
                "optimizer_state_dict": optimizer.state_dict(),
                "loss": best_loss,
                "architecture": {
                    "input_size": model.input_size,
                    "output_size": model.output_size,
                    "n_neurons": model.n_neurons,
                    "dropout_rates": model.dropout_rates,
                },
                "hyperparams": hyperparams,
            }, os.path.join(save_dir, "best_model.pt"))
        else:
            epochs_without_improvement += 1

        # ---------- Logging ----------
        log_msg = f"Epoch [{epoch+1}/{num_epochs}] | Train Loss: {avg_train_loss:.6f}"
        if avg_val_loss is not None:
            log_msg += f" | Val Loss: {avg_val_loss:.6f}"
        log_msg += f" | Best: {best_loss:.6f}"
        print(log_msg)

        # ---------- Early stopping ----------
        if epochs_without_improvement >= patience:
            print(f"Early stopping at epoch {epoch+1} "
                  f"(no improvement for {patience} epochs)")
            break

    # ---------- Final save ----------
    torch.save({
        "epoch": epoch + 1,
        "model_state_dict": model.state_dict(),
        "optimizer_state_dict": optimizer.state_dict(),
        "loss": avg_train_loss if avg_val_loss is None else avg_val_loss,
        "architecture": {
            "input_size": model.input_size,
            "output_size": model.output_size,
            "n_neurons": model.n_neurons,
            "dropout_rates": model.dropout_rates,
        },
        "hyperparams": hyperparams,
    }, os.path.join(save_dir, "final_model.pt"))

    # ---------- Final evaluation: load best model, compute all metrics ----------
    print("\nLoading best model for final evaluation...")
    checkpoint = torch.load(os.path.join(save_dir, "best_model.pt"), map_location=device)
    model.load_state_dict(checkpoint["model_state_dict"])

    print("\nComputing metrics on training set...")
    train_metrics = evaluate_metrics(model, train_loader, device)
    print(f"  Train: {train_metrics}")

    val_metrics = None
    if val_loader is not None:
        print("\nComputing metrics on validation set...")
        val_metrics = evaluate_metrics(model, val_loader, device)
        print(f"  Val:   {val_metrics}")

    # ---------- JSON log ----------
    log_data = {
        "hyperparams": hyperparams,
        "train_loss_history": train_loss_history,
        "val_loss_history": val_loss_history,
        "final_metrics": {
            "train": train_metrics,
            "val": val_metrics,
        },
    }
    with open(os.path.join(save_dir, "training_log.json"), "w") as f:
        json.dump(log_data, f, indent=2)

    print(f"\nTraining complete. Best loss: {best_loss:.6f}")
    print(f"Checkpoints saved to {save_dir}/")

    return {
        "train_loss_history": train_loss_history,
        "val_loss_history": val_loss_history,
        "final_metrics": {"train": train_metrics, "val": val_metrics},
    }