add 'right' option for 'truncation_strategy'

[zsxm1998]

PR type

• Bug Fix
• New Feature
• Document Updates
• More Models or Datasets Support

PR information

A new 'right' parameter has been added to the truncation_strategy, corresponding to right-side truncation. This is necessary, especially in the training of multimodal large models. For instance, if an image is input at the beginning of the data but the model's output exceeds the max_length, left-side truncation alone may result in the image being cut off, causing the model to lose crucial context for generating the result.

Experiment results

No experiment.

[Jintao-Huang]

hello, thanks for your PR.

The delete strategy seems to be able to handle this situation. If a right trim results in an entirely clean response, I believe it will throw an error.