why is the prompt not be learnable?

[yhao-z]

As in the code, the arg learnable_input_prompt is set to be False in default, and when i check the whole model PromptMR, i find that there is no learnable_input_prompt arg, which means that prompt is not learnable. https://github.com/hellopipu/PromptMR/blob/2db837a297f287eec89faf8672503f4f0d630505/models/promptmr.py#L70

This really makes me confused. If the prompt is not learnable, so why it is called prompt? It just has nothing related to the distortion type, just a random noise by initialization. And, why it works as it is a pure noise?

I would really appreciate it if you or anyone else could help me to find it out