Hands-on Examples

import torch
import torch.nn as nn
from torchvision import models, transforms
from torch.utils.data import Dataset, DataLoader
from PIL import Image
import pandas as pd
import os
import numpy as np
from tqdm import tqdm
from sklearn.model_selection import train_test_split

# Camera Position: X, Y, Z, Pitch, Yaw, Roll
CAMERA_POSE = np.array([-8.10, -157, -35.7, 40, -180, 0], dtype=np.float32)

# Paths
CSV_PATH = r"d:\exp\beam_labels.csv"
RGB_DIR = r"E:\Datasets1\San Francisco\Scene 1\roof_bs_01\cam"
DEPTH_DIR = r"E:\Datasets1\San Francisco\Scene 1\roof_bs_01\depth"
CSI_DIR = r"D:\multi_path_npz"  # Path to csi_xxxx.npz files containing uav_pos

BATCH_SIZE = 16
EPOCHS = 20
LEARNING_RATE = 0.001

# --- 1. Dataset ---
class UAVLocDataset(Dataset):
    def __init__(self, csv_file, rgb_dir, depth_dir, csi_dir, transform=None):
        self.df = pd.read_csv(csv_file)
        self.rgb_dir = rgb_dir
        self.depth_dir = depth_dir
        self.csi_dir = csi_dir

        # Static camera pose repeated for each sample
        self.camera_pose = torch.tensor(CAMERA_POSE, dtype=torch.float32)

        if transform is None:
            self.transform = transforms.Compose([
                transforms.Resize((512, 512)),
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
            ])
        else:
            self.transform = transform

        # Depth transform (resize and to tensor)
        self.depth_transform = transforms.Compose([
            transforms.Resize((512, 512)),
            transforms.ToTensor()
        ])

    def __len__(self):
        return len(self.df)

    def __getitem__(self, idx):
        # 1. Filenames
        row = self.df.iloc[idx]
        npz_filename = row['filename'] # csi_xxxxxx.npz
        file_id = npz_filename.replace('csi_', '').replace('.npz', '')

        rgb_name = f"img_{file_id}.png"
        depth_name = f"depth_{file_id}.npz"

        rgb_path = os.path.join(self.rgb_dir, rgb_name)
        depth_path = os.path.join(self.depth_dir, depth_name)
        csi_path = os.path.join(self.csi_dir, npz_filename)

        # 2. Load Inputs (RGB + Depth)
        try:
            # RGB
            rgb_img = Image.open(rgb_path).convert('RGB')
            rgb_tensor = self.transform(rgb_img)

            # Depth
            with np.load(depth_path) as data:
                key = data.files[0]
                depth_arr = data[key]
                depth_img = Image.fromarray(depth_arr, mode='F')

            depth_tensor = self.depth_transform(depth_img) # (1, 512, 512)

            # Early Fusion: Concatenate RGB and Depth -> (4, 512, 512)
            input_img = torch.cat([rgb_tensor, depth_tensor], dim=0)

        except Exception as e:
            print(f"Error loading images for {file_id}: {e}")5
            input_img = torch.zeros(4, 512, 512)

        # 3. Load Label (UAV Position)
        try:
            with np.load(csi_path) as data:
                # 'uav_pos' contains [x, z, y] implicitly based on description
                # Description: y is in 3rd dim (index 2), z in 2nd dim (index 1)
                # target y needs negation
                raw_pos = data['uav_pos'] # shape expected (3,)

                # Coordinate transformation
                # Target: (x, y, z)
                # Ensure 1D and convert to float to avoid shape mismatches (e.g. (3,1) vs (3,))
                raw_pos = raw_pos.flatten()
                t_x = float(raw_pos[0])
                t_z = float(raw_pos[1])  # z is index 1
                t_y = -float(raw_pos[2]) # y is index 2, needs negation

                # Final order: x, y, z
                target_pos = torch.tensor([t_x, t_y, t_z], dtype=torch.float32)

        except Exception as e:
            print(f"Error loading label for {file_id}: {e}")
            target_pos = torch.zeros(3, dtype=torch.float32)

        return input_img, self.camera_pose, target_pos

# --- 2. Network Model ---
class LocRegressionNet(nn.Module):
    def __init__(self, pose_dim=6, output_dim=3):
        super(LocRegressionNet, self).__init__()

        # Backbone (MobileNetV2)
        # Modified input to 4 channels (RGBD)
        self.backbone = models.mobilenet_v2(weights=None)

        original_first_layer = self.backbone.features[0][0]
        self.backbone.features[0][0] = nn.Conv2d(
            in_channels=4,
            out_channels=original_first_layer.out_channels,
            kernel_size=original_first_layer.kernel_size,
            stride=original_first_layer.stride,
            padding=original_first_layer.padding,
            bias=False
        )

        # Remove classifier, use features only
        # MobileNetV2 features output: (1280, 7, 7) for 224x224 input
        # For 512x512 input, spatial dim will be larger (16x16)
        # We use Global Average Pooling to get (1280,)
        self.gap = nn.AdaptiveAvgPool2d(1)
        self.feature_extractor = self.backbone.features

        feature_dim = 1280 # MobileNetV2 last channel

        # Regression Head
        # Concatenate Image Features (1280) + Camera Pose (6) = 1286
        self.regressor = nn.Sequential(
            nn.Linear(feature_dim + pose_dim, 512),
            nn.ReLU(),
            nn.Dropout(0.2),
            nn.Linear(512, 128),
            nn.ReLU(),
            nn.Linear(128, output_dim) # Output: x, y, z
        )

    def forward(self, x_img, x_pose):
        # Image Features
        x = self.feature_extractor(x_img) # (B, 1280, H, W)
        x = self.gap(x)                   # (B, 1280, 1, 1)
        x = torch.flatten(x, 1)           # (B, 1280)

        # Fusion
        combined = torch.cat((x, x_pose), dim=1) # (B, 1286)

        # Regression
        output = self.regressor(combined)
        return output

def main():
    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    print(f"Using device: {device}")

    # Data
    print("Preparing Data...")
    if not os.path.exists(CSV_PATH):
        print(f"Error: CSV file not found at {CSV_PATH}")
        return

    full_df = pd.read_csv(CSV_PATH)
    train_df, test_df = train_test_split(full_df, test_size=0.2, random_state=42)

    # Save temp CSVs
    train_df.to_csv('temp_loc_train.csv', index=False)
    test_df.to_csv('temp_loc_test.csv', index=False)

    train_dataset = UAVLocDataset('temp_loc_train.csv', RGB_DIR, DEPTH_DIR, CSI_DIR)
    test_dataset = UAVLocDataset('temp_loc_test.csv', RGB_DIR, DEPTH_DIR, CSI_DIR)

    train_loader = DataLoader(train_dataset, batch_size=BATCH_SIZE, shuffle=True, num_workers=0)
    test_loader = DataLoader(test_dataset, batch_size=BATCH_SIZE, shuffle=False, num_workers=0)

    # Model
    model = LocRegressionNet().to(device)

    # Loss: MSE for regression
    criterion = nn.MSELoss()
    optimizer = torch.optim.Adam(model.parameters(), lr=LEARNING_RATE)

    print("Starting Training (Regression Task)...")
    best_loss = float('inf')

    for epoch in range(EPOCHS):
        model.train()
        running_loss = 0.0

        loop = tqdm(train_loader, desc=f"Epoch {epoch+1}/{EPOCHS}")
        for imgs, poses, targets in loop:
            imgs = imgs.to(device)
            poses = poses.to(device)
            targets = targets.to(device)

            optimizer.zero_grad()
            outputs = model(imgs, poses)

            loss = criterion(outputs, targets)
            loss.backward()
            optimizer.step()

            running_loss += loss.item()
            loop.set_postfix(mse_loss=loss.item())

        avg_train_loss = running_loss / len(train_loader)

        # Evaluation
        model.eval()
        test_loss = 0.0
        with torch.no_grad():
            for imgs, poses, targets in test_loader:
                imgs = imgs.to(device)
                poses = poses.to(device)
                targets = targets.to(device)

                outputs = model(imgs, poses)
                loss = criterion(outputs, targets)
                test_loss += loss.item()

        avg_test_loss = test_loss / len(test_loader)

        print(f"Epoch {epoch+1}: Train MSE={avg_train_loss:.4f}, Test MSE={avg_test_loss:.4f}, Test RMSE={np.sqrt(avg_test_loss):.4f}")

        if avg_test_loss < best_loss:
            best_loss = avg_test_loss
            torch.save(model.state_dict(), "best_uav_loc_model.pth")
            print("  [Saved Best Model]")

    print(f"Training Finished! Best Test MSE: {best_loss:.4f}")

    # Clean up
    if os.path.exists('temp_loc_train.csv'): os.remove('temp_loc_train.csv')
    if os.path.exists('temp_loc_test.csv'): os.remove('temp_loc_test.csv')

if __name__ == "__main__":
    main()

import numpy as np
import os
import glob
import pandas as pd

# --- Configuration ---
FC = 4.9e9  # Carrier frequency 4.9 GHz
C = 299792458  # Speed of light
WAVELENGTH = C / FC
ANTENNA_SPACING = WAVELENGTH / 2  # Half-wavelength spacing

# BS Antenna Config (8x8 UPA)
Nx, Ny = 8, 8
NUM_ANTENNAS = Nx * Ny

# Beam Config (Oversampled)
Mx, My = 16, 16  # 16x16 = 256 beams
NUM_BEAMS = Mx * My


def get_upa_steering_vector(theta, phi, N_x, N_y):
    """
    Generate UPA steering vector.
    theta: Elevation angle (0-180, 0 is zenith)
    phi: Azimuth angle (-180-180)
    """
    # Radian input
    theta_rad = theta
    phi_rad = phi

    # Antenna index grid
    # Array in XY plane
    m = np.arange(N_x)
    n = np.arange(N_y)

    # Spatial frequencies u, v
    # u: x-axis phase change
    # v: y-axis phase change
    u = np.sin(theta_rad) * np.cos(phi_rad)
    v = np.sin(theta_rad) * np.sin(phi_rad)

    # Generate steering vectors
    # a_x shape (Nx, 1), a_y shape (Ny, 1)
    a_x = np.exp(1j * 2 * np.pi * 0.5 * m * u)
    a_y = np.exp(1j * 2 * np.pi * 0.5 * n * v)

    # Kronecker product for full array response
    # output shape: (Nx*Ny, )
    steering_vector = np.kron(a_x, a_y)

    return steering_vector


def build_channel_from_multipath(npz_path):
    """
    Read multipath data from .npz and synthesize MISO channel vector h.
    """
    data = np.load(npz_path)

    # 1. Extract multipath components
    # Flatten to avoid shape mismatch

    # Complex gains
    alphas = (data['a_real'] + 1j * data['a_imag']).flatten()
    # Angles (AoD for BS)
    thetas_t = data['theta_t'].flatten()
    phis_t = data['phi_t'].flatten()
    # Delays
    taus = data['tau'].flatten()

    # 2. Init channel vector h (64,)
    h = np.zeros(NUM_ANTENNAS, dtype=complex)

    # 3. Sum of Paths
    # Assume Rx steering vector is 1 (MISO)

    num_paths = len(alphas)
    for i in range(num_paths):
        # Phase shift (Delay Term)
        phase_shift = np.exp(-1j * 2 * np.pi * FC * taus[i])

        # Path coefficient
        path_coeff = alphas[i] * phase_shift

        # Tx Steering Vector
        a_t = get_upa_steering_vector(thetas_t[i], phis_t[i], Nx, Ny)

        # Accumulate
        h += path_coeff * a_t

    return h


def create_oversampled_dft_codebook(N, M):
    """
    Create Oversampled DFT codebook.
    N: Number of antennas
    M: Number of beams
    Returns matrix of shape (N, M)
    """
    n = np.arange(N)
    k = np.arange(M)
    # DFT vectors: exp(j * 2 * pi * n * k / M)
    # Normalized by sqrt(N) to maintain unit power (per antenna element scaling)
    # W[n, k]
    W = np.exp(1j * 2 * np.pi * np.outer(n, k) / M) / np.sqrt(N)
    return W


def create_codebook(N_x, N_y, M_x, M_y):
    """
    Create 2D Oversampled DFT codebook.
    Codebook size = (Nx * Ny, Mx * My)
    """
    # X-dim DFT matrix (Nx antennas, Mx beams)
    Fx = create_oversampled_dft_codebook(N_x, M_x)

    # Y-dim DFT matrix (Ny antennas, My beams)
    Fy = create_oversampled_dft_codebook(N_y, M_y)

    # 2D-DFT Codebook via Kronecker product
    # Codebook shape: (Nx*Ny, Mx*My)
    # Each column is a beam codeword
    Codebook = np.kron(Fx, Fy)
    return Codebook


def get_optimal_beam_label(h, codebook):
    """
    Calculate optimal beam index.
    h: Channel vector (Num_Antennas, )
    codebook: Codebook matrix (Num_Antennas, Num_Beams)
    """
    # 1. Beamforming: Calculate signal strength
    # Transpose conjugate
    # received_signals shape: (Num_Beams, )
    received_signals = codebook.conj().T @ h

    # 2. Calculate power
    powers = np.abs(received_signals) ** 2

    # 3. Find index of max power
    best_beam_idx = np.argmax(powers)

    return best_beam_idx, powers


# --- Batch Processing ---
if __name__ == "__main__":
    # Paths
    INPUT_DIR = r"D:\multi_path_npz"
    # Save results to script dir
    OUTPUT_CSV = os.path.join(os.path.dirname(os.path.abspath(__file__)), "beam_labels.csv")

    # 1. Generate Codebook
    print(f"Generating Oversampled DFT Codebook ({Mx}x{My} = {NUM_BEAMS} beams)...")
    try:
        W = create_codebook(Nx, Ny, Mx, My)
        print(f"Codebook shape: {W.shape}")

        # 2. Get all .npz files
        pattern = os.path.join(INPUT_DIR, "csi_*.npz")
        files = sorted(glob.glob(pattern))
        print(f"Found {len(files)} data files.")

        results = []

        # 3. Batch processing
        print("Starting batch processing...")
        for idx, file_path in enumerate(files):
            try:
                # Parse filename
                filename = os.path.basename(file_path)

                # Generate channel
                h_channel = build_channel_from_multipath(file_path)

                # Get label
                label, power_vectors = get_optimal_beam_label(h_channel, W)
                max_power = power_vectors[label]

                results.append({
                    'filename': filename,
                    'beam_index': label,
                    'received_power': max_power
                })

                # Log progress every 100 files
                if (idx + 1) % 100 == 0:
                    print(f"Processed {idx + 1}/{len(files)} files...")

            except Exception as e:
                print(f"Error processing {filename}: {e}")

        # 4. Save results
        if results:
            df = pd.DataFrame(results)
            df.to_csv(OUTPUT_CSV, index=False)
            print(f"\nFinished! Results saved to: {OUTPUT_CSV}")
            print("First 5 rows:")
            print(df.head())
        else:
            print("No results generated. Please check the paths.")

    except Exception as e:
        print(f"An error occurred: {e}")

import torch
import torch.nn as nn
from torchvision import models, transforms
from torch.utils.data import Dataset, DataLoader
from PIL import Image
import pandas as pd
import os
import numpy as np


# --- 1. Network Model Design (Based on MobileNetV2) ---
class ISAC_MobileNet(nn.Module):
    def __init__(self, num_classes=256, in_channels=4, pretrained=False):
        super(ISAC_MobileNet, self).__init__()

        # Load MobileNetV2
        # pretrained=False: Random initialization, no ImageNet weights
        self.backbone = models.mobilenet_v2(weights=None)

        # --- Modify Input Layer ---
        # Modify first layer to accept custom channels (RGB+D=4, RGB=3, Depth=1)
        original_first_layer = self.backbone.features[0][0]

        # Create new conv layer with specified input channels
        new_first_layer = nn.Conv2d(
            in_channels=in_channels,
            out_channels=original_first_layer.out_channels,
            kernel_size=original_first_layer.kernel_size,
            stride=original_first_layer.stride,
            padding=original_first_layer.padding,
            bias=False
        )

        # Replace the first layer
        self.backbone.features[0][0] = new_first_layer

        # --- Modify Output Layer (Classifier) ---
        # MobileNetV2 classifier is classifier[1]
        in_features = self.backbone.classifier[1].in_features
        self.backbone.classifier[1] = nn.Linear(in_features, num_classes)

    def forward(self, x):
        return self.backbone(x)


# --- 2. Data Loader Design ---
class RGBDBeamDataset(Dataset):
    def __init__(self, csv_file, rgb_dir, depth_dir, transform=None):
        """
        csv_file: path to beam_labels.csv generated by generateH.py
        rgb_dir: path to RGB image directory
        depth_dir: path to depth map directory
        """
        self.df = pd.read_csv(csv_file)
        self.rgb_dir = rgb_dir
        self.depth_dir = depth_dir

        # Default preprocessing
        if transform is None:
            self.transform = transforms.Compose([
                transforms.Resize((512, 512)),  # Resize to 512x512
                transforms.ToTensor(),  # ToTensor (normalizes to [0,1])
            ])
        else:
            self.transform = transform

        # RGB Normalization (ImageNet stats)
        self.rgb_normalize = transforms.Normalize(
            mean=[0.485, 0.456, 0.406],
            std=[0.229, 0.224, 0.225]
        )

    def __len__(self):
        return len(self.df)

    def __getitem__(self, idx):
        # 1. Get filename and label
        row = self.df.iloc[idx]
        npz_name = row['filename']  # e.g., csi_000000.npz
        label = int(row['beam_index'])

        # 2. Construct filenames
        # e.g., csi_000000.npz -> 000000
        file_id = npz_name.replace('csi_', '').replace('.npz', '')

        # Modify filename format
        rgb_name = f"img_{file_id}.png"
        depth_name = f"depth_{file_id}.npz" # Depth in .npz format

        rgb_path = os.path.join(self.rgb_dir, rgb_name)
        depth_path = os.path.join(self.depth_dir, depth_name)

        # 3. Load images
        try:
            # Load RGB (PIL default)
            rgb_img = Image.open(rgb_path).convert('RGB')

            # Load Depth (.npz)
            with np.load(depth_path) as data:
                # Assume single array or unknown key
                key = data.files[0]
                depth_arr = data[key] # Read as numpy array

                # Assume float depth
                depth_img = Image.fromarray(depth_arr, mode='F') # mode='F' (32-bit float)

        except Exception as e:
            print(f"Error reading image: {rgb_path} or {depth_path} : {e}")
            # Return dummy data on error
            return torch.zeros(4, 512, 512), label

        # 4. Preprocessing
        # Ensure consistent resize for RGB and Depth
        rgb_tensor = self.transform(rgb_img)  # (3, 512, 512), range [0, 1]
        depth_tensor = self.transform(depth_img)  # (1, 512, 512), range [0, 1]

        # 5. Normalization
        rgb_tensor = self.rgb_normalize(rgb_tensor)  # Normalize RGB

        # 6. Early Fusion
        # Concat channel dim -> (4, 512, 512)
        input_tensor = torch.cat([rgb_tensor, depth_tensor], dim=0)

        return input_tensor, label


# --- 3. Training/Testing Example ---
if __name__ == "__main__":
    from sklearn.model_selection import train_test_split
    from tqdm import tqdm

    # --- 1. Settings ---
    csv_path = r"d:\exp\beam_labels.csv"
    rgb_path = r"E:\Datasets1\San Francisco\Scene 1\roof_bs_01\cam"
    depth_path = r"E:\Datasets1\San Francisco\Scene 1\roof_bs_01\depth"

    BATCH_SIZE = 16
    EPOCHS = 10
    LEARNING_RATE = 0.001

    # Auto device selection
    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    print(f"Using device: {device}")

    # --- 2. Data Splitting ---
    # Load full data
    full_df = pd.read_csv(csv_path)

    # Split train (80%) and test (20%)
    train_df, test_df = train_test_split(full_df, test_size=0.2, random_state=42, shuffle=True)

    # Save temp files for Dataset
    train_df.to_csv('temp_train.csv', index=False)
    test_df.to_csv('temp_test.csv', index=False)

    train_dataset = RGBDBeamDataset('temp_train.csv', rgb_path, depth_path)
    test_dataset = RGBDBeamDataset('temp_test.csv', rgb_path, depth_path)

    train_loader = DataLoader(train_dataset, batch_size=BATCH_SIZE, shuffle=True, num_workers=0)
    test_loader = DataLoader(test_dataset, batch_size=BATCH_SIZE, shuffle=False, num_workers=0)

    # --- 3. Model, Loss, Optimizer ---
    # Instantiate 3 models for ablation study
    print("Initializing models for Ablation Study...")

    # 1. RGB+Depth (4 channels)
    model_all = ISAC_MobileNet(num_classes=256, in_channels=4, pretrained=False).to(device)
    opt_all = torch.optim.Adam(model_all.parameters(), lr=LEARNING_RATE)

    # 2. RGB Only (3 channels)
    model_rgb = ISAC_MobileNet(num_classes=256, in_channels=3, pretrained=False).to(device)
    opt_rgb = torch.optim.Adam(model_rgb.parameters(), lr=LEARNING_RATE)

    # 3. Depth Only (1 channel)
    model_depth = ISAC_MobileNet(num_classes=256, in_channels=1, pretrained=False).to(device)
    opt_depth = torch.optim.Adam(model_depth.parameters(), lr=LEARNING_RATE)

    criterion = nn.CrossEntropyLoss()

    # --- 4. Training Loop ---
    print("\nStarting Parallel Training for 3 Models...")
    best_acc_all = 0.0
    best_acc_rgb = 0.0
    best_acc_depth = 0.0

    for epoch in range(EPOCHS):
        model_all.train()
        model_rgb.train()
        model_depth.train()

        # Statistics for 3 models
        stats = {
            'all': {'loss': 0.0, 'correct': 0},
            'rgb': {'loss': 0.0, 'correct': 0},
            'depth': {'loss': 0.0, 'correct': 0},
            'total': 0
        }

        loop = tqdm(train_loader, desc=f"Epoch {epoch+1}/{EPOCHS}")
        for inputs, labels in loop:
            # Prepare inputs on GPU
            inputs = inputs.to(device)
            labels = labels.to(device)

            # Split inputs
            # inputs is [B, 4, H, W] -> RGB=[B, :3, ...], Depth=[B, 3:, ...]
            input_rgb = inputs[:, :3, :, :]
            input_depth = inputs[:, 3:, :, :]

            # --- Train Model 1 (RGB+D) ---
            opt_all.zero_grad()
            out_all = model_all(inputs)
            loss_all = criterion(out_all, labels)
            loss_all.backward()
            opt_all.step()

            # --- Train Model 2 (RGB) ---
            opt_rgb.zero_grad()
            out_rgb = model_rgb(input_rgb)
            loss_rgb = criterion(out_rgb, labels)
            loss_rgb.backward()
            opt_rgb.step()

            # --- Train Model 3 (Depth) ---
            opt_depth.zero_grad()
            out_depth = model_depth(input_depth)
            loss_depth = criterion(out_depth, labels)
            loss_depth.backward()
            opt_depth.step()

            # --- Stats Update ---
            stats['total'] += labels.size(0)

            # RGB+D
            stats['all']['loss'] += loss_all.item()
            _, pred_all = torch.max(out_all.data, 1)
            stats['all']['correct'] += (pred_all == labels).sum().item()

            # RGB
            stats['rgb']['loss'] += loss_rgb.item()
            _, pred_rgb = torch.max(out_rgb.data, 1)
            stats['rgb']['correct'] += (pred_rgb == labels).sum().item()

            # Depth
            stats['depth']['loss'] += loss_depth.item()
            _, pred_depth = torch.max(out_depth.data, 1)
            stats['depth']['correct'] += (pred_depth == labels).sum().item()

            loop.set_postfix({
                'L_All': f"{loss_all.item():.2f}",
                'L_RGB': f"{loss_rgb.item():.2f}",
                'L_Dep': f"{loss_depth.item():.2f}"
            })

        # Calculate epoch metrics
        num_batches = len(train_loader)
        total_samples = stats['total']

        train_res = {}
        for k in ['all', 'rgb', 'depth']:
            train_res[k] = {
                'loss': stats[k]['loss'] / num_batches,
                'acc': stats[k]['correct'] / total_samples
            }

        # --- 5. Testing/Validation ---
        model_all.eval()
        model_rgb.eval()
        model_depth.eval()

        test_stats = {
            'all': {'correct': 0, 'top5': 0},
            'rgb': {'correct': 0, 'top5': 0},
            'depth': {'correct': 0, 'top5': 0},
            'total': 0
        }

        with torch.no_grad():
            for inputs, labels in test_loader:
                inputs = inputs.to(device)
                labels = labels.to(device)
                input_rgb = inputs[:, :3, :, :]
                input_depth = inputs[:, 3:, :, :]

                test_stats['total'] += labels.size(0)

                # Helper function for eval
                def eval_batch(model, x, key):
                    out = model(x)
                    # Top 1
                    _, pred = torch.max(out.data, 1)
                    test_stats[key]['correct'] += (pred == labels).sum().item()
                    # Top 5
                    _, top5 = out.topk(5, 1, True, True)
                    top5 = top5.t()
                    correct_row = top5.eq(labels.view(1, -1).expand_as(top5))
                    test_stats[key]['top5'] += correct_row.reshape(-1).float().sum().item()

                eval_batch(model_all, inputs, 'all')
                eval_batch(model_rgb, input_rgb, 'rgb')
                eval_batch(model_depth, input_depth, 'depth')

        # Print Results
        print(f"\nEpoch {epoch+1} Results:")
        print(f"  [RGB+D] Train Loss: {train_res['all']['loss']:.4f}, Acc: {train_res['all']['acc']:.4f} | "
              f"Test Acc: {test_stats['all']['correct']/test_stats['total']:.4f}, Top5: {test_stats['all']['top5']/test_stats['total']:.4f}")
        print(f"  [RGB ]  Train Loss: {train_res['rgb']['loss']:.4f}, Acc: {train_res['rgb']['acc']:.4f} | "
              f"Test Acc: {test_stats['rgb']['correct']/test_stats['total']:.4f}, Top5: {test_stats['rgb']['top5']/test_stats['total']:.4f}")
        print(f"  [Depth] Train Loss: {train_res['depth']['loss']:.4f}, Acc: {train_res['depth']['acc']:.4f} | "
              f"Test Acc: {test_stats['depth']['correct']/test_stats['total']:.4f}, Top5: {test_stats['depth']['top5']/test_stats['total']:.4f}")

        # Save Checkpoints
        current_acc_all = test_stats['all']['correct']/test_stats['total']
        current_acc_rgb = test_stats['rgb']['correct']/test_stats['total']
        current_acc_depth = test_stats['depth']['correct']/test_stats['total']

        if current_acc_all > best_acc_all:
            best_acc_all = current_acc_all
            torch.save(model_all.state_dict(), "best_model_rgbd.pth")

        if current_acc_rgb > best_acc_rgb:
            best_acc_rgb = current_acc_rgb
            torch.save(model_rgb.state_dict(), "best_model_rgb.pth")

        if current_acc_depth > best_acc_depth:
            best_acc_depth = current_acc_depth
            torch.save(model_depth.state_dict(), "best_model_depth.pth")

    print(f"\nTraining Finished!")
    print(f"Best Acc - RGB+D: {best_acc_all:.4f}, RGB: {best_acc_rgb:.4f}, Depth: {best_acc_depth:.4f}")

    # Clean temp files
    if os.path.exists('temp_train.csv'): os.remove('temp_train.csv')
    if os.path.exists('temp_test.csv'): os.remove('temp_test.csv')