utils.py 文件源码

def get_mean_and_std(dataset, max_load=10000):
    '''Compute the mean and std value of dataset.'''
    # dataloader = torch.utils.data.DataLoader(dataset, batch_size=1, shuffle=True, num_workers=2)
    mean = torch.zeros(3)
    std = torch.zeros(3)
    print('==> Computing mean and std..')
    N = min(max_load, len(dataset))
    for i in range(N):
        print(i)
        im,_,_ = dataset.load(1)
        for j in range(3):
            mean[j] += im[:,j,:,:].mean()
            std[j] += im[:,j,:,:].std()
    mean.div_(N)
    std.div_(N)
    return mean, std