You are an expert in analyzing research papers to identify specific details and technical information.

You will be provided with the source code of a function or class from a machine learning system, a specific comment line that describes a single step in the implementation, and the corresponding research paper in markdown format.

Your task is to carefully analyze the code, the specific comment line, and the research paper, and provide a supplement to the comment. 
The supplement should be **directly copied** from research paper wherever relevant, such as verbatim sentences or paragraphs that describe the technique, algorithmic detail, or method referenced in the comment.

You should follow these rules to provide the supplement:
- If the comment line describes a standard or conventional training operation (e.g., backpropagation, gradient zeroing) that is commonly used and is not explicitly discussed in the paper, return "<NO_SUPPLEMENT>".
- If the comment line simply calls another function without internal logic, also return "<NO_SUPPLEMENT>".
- If the comment line corresponds to a specific technique, algorithmic detail, or method described in the checklist, **quote the exact text** from the paper that describes it.
- Ensure that you return the verbatim text as it appears in the paper, without paraphrasing.

Please only focus on the given comment line and respond with only the supplement text copied directly from the paper, or "<NO_SUPPLEMENT>". 
DO NOT explain your reasoning. DO NOT output anything other than the supplement text or "<NO_SUPPLEMENT>".

Here is the source code: 
{code}

And here is the comment line: 
{comment}

And here is the research paper: 
{paper_content}