Investigating overestimation of total parameter counts for multiple models

[6DammK9]

Describe the bug
Total params of the model may be overestmated up to 2.37x for multiple models, meanwhile other models remains accurate.

• YOLOv8 from ultralytics, or YOLOv10
• RN50 from Chinese-CLIP
• T5 from transformers
• SD2.1 from diffusers, UNet2DConditionModel in precise

I wonder if there is something common across these models, yielding some double count and hence the overestimated result.

To Reproduce

• Run this code snippet directly. Ref

from ultralytics import YOLO
from torchinfo import summary

# Load the yolov10n model
model = YOLO("yolov10n.pt")

# It is a pytorch model, so we count it directrly.
pytorch_total_params = sum(p.numel() for p in model.parameters())

# Pass model will trigger model.train which is not good.
model_summary = summary(model.model, 
    #input_data="path/to/bus.jpg",
    input_size=(1,3,640,640), 
    col_names=("input_size", "output_size", "num_params")
)

with open('summary.txt', 'w', encoding='utf-8') as the_file:
    the_file.write(f"{str(model_summary)}\r\nTotal Params (torch): {str(pytorch_total_params)}\r\nTotal Params (info): {model.info()}")

• My ipynb would be a lot more sophisticated, including intercepting the input data within the pipeline. The counts should remains the same. The inaccurate result will be kind of 2.0b vs 860M (SD1), 2.1b vs 865M (SD2), and 5.3b vs 2.6b (SDXL).

Expected behavior
Viewing the generated summary.txt will see the inconsistent result, which is overestimated for 1.78x. Official claims 2.3M but model.info() used the same nn.numel() approach which gives 2775520 also.

...
│    │    └─DFL: 3-137                                       [1, 64, 8400]             [1, 4, 8400]              (16)
=======================================================================================================================================
Total params: 4,932,416
Trainable params: 0
Non-trainable params: 4,932,416
Total mult-adds (Units.GIGABYTES): 4.29
=======================================================================================================================================
Input size (MB): 4.92
Forward/backward pass size (MB): 362.66
Params size (MB): 11.10
Estimated Total Size (MB): 378.68
=======================================================================================================================================

Total Params (torch): 2775520

Total Params (info): (385, 2775520, 0, 8.7404288)

Runtime environment

• Python 3.10 under conda

torch==2.4.0+cu124
diffusers==0.30.0
transformers==4.44.0

[TylerYep]

Hmm, perhaps recursive layers? Not sure what this could be