如何解决 ValueError：没有足够的值来解包错误

这些是 pytorch-yolo v3 代码。我是在github下载的。( https://github.com/eriklindernoren/PyTorch-YOLOv3 ) 我为两个类调整了这个。在我进行训练时，仍然存在错误。

这是 test.py 代码。

from __future__ import division

from models import *
from utils.utils import *
from utils.datasets import *
from utils.parse_config import *

import os
import sys
import time
import datetime
import argparse
import tqdm

import torch
from torch.utils.data import DataLoader
from torchvision import datasets
from torchvision import transforms
from torch.autograd import Variable
import torch.optim as optim


def evaluate(model, path, iou_thres, conf_thres, nms_thres, img_size, batch_size):
    model.eval()

    # Get dataloader
    dataset = ListDataset(path, img_size=img_size, augment=False, multiscale=False)
    dataloader = torch.utils.data.DataLoader(
        dataset, batch_size=batch_size, shuffle=False, num_workers=1, collate_fn=dataset.collate_fn
    )

    Tensor = torch.cuda.FloatTensor if torch.cuda.is_available() else torch.FloatTensor

    labels = []
    sample_metrics = []  # List of tuples (TP, confs, pred)
    for batch_i, (_, imgs, targets) in enumerate(tqdm.tqdm(dataloader, desc="Detecting objects")):

        # Extract labels
        labels += targets[:, 1].tolist()
        # Rescale target
        targets[:, 2:] = xywh2xyxy(targets[:, 2:])
        targets[:, 2:] *= img_size

        imgs = Variable(imgs.type(Tensor), requires_grad=False)

        with torch.no_grad():
            outputs = model(imgs)
            outputs = non_max_suppression(outputs, conf_thres=conf_thres, nms_thres=nms_thres)

        sample_metrics += get_batch_statistics(outputs, targets, iou_threshold=iou_thres)

    # Concatenate sample statistics
    true_positives, pred_scores, pred_labels = [np.concatenate(x, 0) for x in list(zip(*sample_metrics))]
    precision, recall, AP, f1, ap_class = ap_per_class(true_positives, pred_scores, pred_labels, labels)

    return precision, recall, AP, f1, ap_class


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--batch_size", type=int, default=8, help="size of each image batch")
    parser.add_argument("--model_def", type=str, default="config/yolov3.cfg", help="path to model definition file")
    parser.add_argument("--data_config", type=str, default="config/coco.data", help="path to data config file")
    parser.add_argument("--weights_path", type=str, default="weights/yolov3.weights", help="path to weights file")
    parser.add_argument("--class_path", type=str, default="data/coco.names", help="path to class label file")
    parser.add_argument("--iou_thres", type=float, default=0.5, help="iou threshold required to qualify as detected")
    parser.add_argument("--conf_thres", type=float, default=0.001, help="object confidence threshold")
    parser.add_argument("--nms_thres", type=float, default=0.5, help="iou thresshold for non-maximum suppression")
    parser.add_argument("--n_cpu", type=int, default=8, help="number of cpu threads to use during batch generation")
    parser.add_argument("--img_size", type=int, default=416, help="size of each image dimension")
    opt = parser.parse_args()
    print(opt)

    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")

    data_config = parse_data_config(opt.data_config)
    valid_path = data_config["valid"]
    class_names = load_classes(data_config["names"])

    # Initiate model
    model = Darknet(opt.model_def).to(device)
    if opt.weights_path.endswith(".weights"):
        # Load darknet weights
        model.load_darknet_weights(opt.weights_path)
    else:
        # Load checkpoint weights
        model.load_state_dict(torch.load(opt.weights_path))

    print("Compute mAP...")

    precision, recall, AP, f1, ap_class = evaluate(
        model,
        path=valid_path,
        iou_thres=opt.iou_thres,
        conf_thres=opt.conf_thres,
        nms_thres=opt.nms_thres,
        img_size=opt.img_size,
        batch_size=8,
    )

    print("Average Precisions:")
    for i, c in enumerate(ap_class):
        print(f"+ Class '{c}' ({class_names[c]}) - AP: {AP[i]}")

    print(f"mAP: {AP.mean()}")

而且，这是 trainplate.py 代码。（最初，这是 train.py。但是，我重命名了它。）

from models import *
from utils.logger import *
from utils.utils import *
from utils.datasets import *
from utils.parse_config import *
from test import evaluate

from terminaltables import AsciiTable

import os
import sys
import time
import datetime
import argparse

import torch
from torch.utils.data import DataLoader
from torchvision import datasets
from torchvision import transforms
from torch.autograd import Variable
import torch.optim as optim

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--epochs", type=int, default=3, help="number of epochs")
    parser.add_argument("--batch_size", type=int, default=8, help="size of each image batch")
    parser.add_argument("--gradient_accumulations", type=int, default=2, help="number of gradient accums before step")
    parser.add_argument("--model_def", type=str, default="config/yolov3plate.cfg", help="path to model definition file")
    parser.add_argument("--data_config", type=str, default="config/plate.data", help="path to data config file")
    parser.add_argument("--pretrained_weights", type=str, help="if specified starts from checkpoint model")
    parser.add_argument("--n_cpu", type=int, default=8, help="number of cpu threads to use during batch generation")
    parser.add_argument("--img_size", type=int, default=416, help="size of each image dimension")
    parser.add_argument("--checkpoint_interval", type=int, default=1, help="interval between saving model weights")
    parser.add_argument("--evaluation_interval", type=int, default=1, help="interval evaluations on validation set")
    parser.add_argument("--compute_map", default=False, help="if True computes mAP every tenth batch")
    parser.add_argument("--multiscale_training", default=True, help="allow for multi-scale training")
    opt = parser.parse_args()
    print(opt)

    logger = Logger("logs")

    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")

    os.makedirs("output", exist_ok=True)
    os.makedirs("checkpoints", exist_ok=True)

    # Get data configuration
    data_config = parse_data_config(opt.data_config)
    train_path = data_config["train"]
    valid_path = data_config["valid"]
    class_names = load_classes(data_config["names"])

    # Initiate model
    model = Darknet(opt.model_def).to(device)
    model.apply(weights_init_normal)

    # If specified we start from checkpoint
    if opt.pretrained_weights:
        if opt.pretrained_weights.endswith(".pth"):
            model.load_state_dict(torch.load(opt.pretrained_weights))
        else:
            model.load_darknet_weights(opt.pretrained_weights)

    # Get dataloader
    dataset = ListDataset(train_path, augment=True, multiscale=opt.multiscale_training)
    dataloader = torch.utils.data.DataLoader(
        dataset,
        batch_size=opt.batch_size,
        shuffle=True,
        num_workers=opt.n_cpu,
        pin_memory=True,
        collate_fn=dataset.collate_fn,
    )

    optimizer = torch.optim.Adam(model.parameters())

    metrics = [
        "grid_size",
        "loss",
        "x",
        "y",
        "w",
        "h",
        "conf",
        "cls",
        "cls_acc",
        "recall50",
        "recall75",
        "precision",
        "conf_obj",
        "conf_noobj",
    ]

    for epoch in range(opt.epochs):
        model.train()
        start_time = time.time()
        for batch_i, (_, imgs, targets) in enumerate(dataloader):
            batches_done = len(dataloader) * epoch + batch_i

            imgs = Variable(imgs.to(device))
            targets = Variable(targets.to(device), requires_grad=False)

            loss, outputs = model(imgs, targets)
            loss.backward()

            if batches_done % opt.gradient_accumulations:
                # Accumulates gradient before each step
                optimizer.step()
                optimizer.zero_grad()

            # ----------------
            #   Log progress
            # ----------------

            log_str = "\n---- [Epoch %d/%d, Batch %d/%d] ----\n" % (epoch, opt.epochs, batch_i, len(dataloader))

            metric_table = [["Metrics", *[f"YOLO Layer {i}" for i in range(len(model.yolo_layers))]]]

            # Log metrics at each YOLO layer
            for i, metric in enumerate(metrics):
                formats = {m: "%.6f" for m in metrics}
                formats["grid_size"] = "%2d"
                formats["cls_acc"] = "%.2f%%"
                row_metrics = [formats[metric] % yolo.metrics.get(metric, 0) for yolo in model.yolo_layers]
                metric_table += [[metric, *row_metrics]]

                # Tensorboard logging
                tensorboard_log = []
                for j, yolo in enumerate(model.yolo_layers):
                    for name, metric in yolo.metrics.items():
                        if name != "grid_size":
                            tensorboard_log += [(f"{name}_{j+1}", metric)]
                tensorboard_log += [("loss", loss.item())]
                logger.list_of_scalars_summary(tensorboard_log, batches_done)

            log_str += AsciiTable(metric_table).table
            log_str += f"\nTotal loss {loss.item()}"

            # Determine approximate time left for epoch
            epoch_batches_left = len(dataloader) - (batch_i + 1)
            time_left = datetime.timedelta(seconds=epoch_batches_left * (time.time() - start_time) / (batch_i + 1))
            log_str += f"\n---- ETA {time_left}"

            print(log_str)

            model.seen += imgs.size(0)

        if epoch % opt.evaluation_interval == 0:
            print("\n---- Evaluating Model ----")
            # Evaluate the model on the validation set
            precision, recall, AP, f1, ap_class = evaluate(
                model,
                path=valid_path,
                iou_thres=0.5,
                conf_thres=0.5,
                nms_thres=0.5,
                img_size=opt.img_size,
                batch_size=8,
            )
            evaluation_metrics = [
                ("val_precision", precision.mean()),
                ("val_recall", recall.mean()),
                ("val_mAP", AP.mean()),
                ("val_f1", f1.mean()),
            ]
            logger.list_of_scalars_summary(evaluation_metrics, epoch)

            # Print class APs and mAP
            ap_table = [["Index", "Class name", "AP"]]
            for i, c in enumerate(ap_class):
                ap_table += [[c, class_names[c], "%.5f" % AP[i]]]
            print(AsciiTable(ap_table).table)
            print(f"---- mAP {AP.mean()}")

        if epoch % opt.checkpoint_interval == 0:
            torch.save(model.state_dict(), f"checkpoints/yolov3_ckpt_%d.pth" % epoch)

每当我运行 trainplate.py 代码时，我都会收到以下 ValueErrorr：我该怎么办？

---- Evaluating Model ----
Detecting objects: 0it [00:00, ?it/s]
Traceback (most recent call last):
  File "C:/Users/jr291/Desktop/연구/PyTorch-YOLOv3/trainplate.py", line 160, in <module>
    batch_size=8,
  File "C:\Users\jr291\Desktop\연구\PyTorch-YOLOv3\test.py", line 53, in evaluate
    true_positives, pred_scores, pred_labels = [np.concatenate(x, 0) for x in list(zip(*sample_metrics))]
ValueError: not enough values to unpack (expected 3, got 0)

此外，get_batch_statistics 函数如下所示。

def get_batch_statistics(outputs, targets, iou_threshold):
    """ Compute true positives, predicted scores and predicted labels per sample """
    batch_metrics = []
    for sample_i in range(len(outputs)):

        if outputs[sample_i] is None:
            continue

        output = outputs[sample_i]
        pred_boxes = output[:, :4]
        pred_scores = output[:, 4]
        pred_labels = output[:, -1]

        true_positives = np.zeros(pred_boxes.shape[0])

        annotations = targets[targets[:, 0] == sample_i][:, 1:]
        target_labels = annotations[:, 0] if len(annotations) else []
        if len(annotations):
            detected_boxes = []
            target_boxes = annotations[:, 1:]

            for pred_i, (pred_box, pred_label) in enumerate(zip(pred_boxes, pred_labels)):

                # If targets are found break
                if len(detected_boxes) == len(annotations):
                    break

                # Ignore if label is not one of the target labels
                if pred_label not in target_labels:
                    continue

                iou, box_index = bbox_iou(pred_box.unsqueeze(0), target_boxes).max(0)
                if iou >= iou_threshold and box_index not in detected_boxes:
                    true_positives[pred_i] = 1
                    detected_boxes += [box_index]
        batch_metrics.append([true_positives, pred_scores, pred_labels])
    return batch_metrics