# Trial checkpointing

**URL:** <https://discuss.ray.io/t/trial-checkpointing/11058>\
**Category:** Uncategorized\
**Created:** [June 16, 2023, 2:05pm UTC](https://discuss.ray.io/t/trial-checkpointing/11058 "2023-06-16T14:05:16Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Jaydeen](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/jaydeen/32/4591_2.png) [@Jaydeen](https://discuss.ray.io/u/Jaydeen)\
**Post date:** [June 16, 2023, 2:05pm UTC](https://discuss.ray.io/t/trial-checkpointing/11058/1 "2023-06-16T14:05:16Z")

</div>

Hi!  
I am in the process of updating my training from ray 1.13 to ray 2.5; Unfortunately, I have trouble understanding the updates checkpointing mechanism. To create checkpoints, I used to do

```auto
with tune.checkpoint_dir(step=epoch) as checkpoint_dir:
      # save everything I wanted manually here

```

This would save all data I wanted in a directory called “checkpoint\_[epoch]” in my trials folder. Also, ray would know about the checkpoint automatically.  
To load my checkpoint, I would do sth like this:

```auto
def my_trainable(config, checkpoint_dir = None):
        if checkpoint_dir is not None:
          model_path = os.path.join(checkpoint_dir, "model.pt")
          model_state = torch.load(model_path)
          start_epoch_num = last_epoch_num + 1 # last_epoch_num read from folder
          net.load_state_dict(model_state, map_location=device)
          net.to(device)
          ....

```

Basically, I am trying to achieve the same behavior with the new API. But:

1. If I use “Checkpoint a dictionary” I would need to fill everything I want to save in a python directory that is saved as one in the “checkpoint\_[epoch]” folder, correct? I find this tedious, since I later would always need to load the whole dict when wanting to read partial results.
2. It seems I want to use “Checkpoint a directory”. However, why do I have to write in a “manual folder” and ray will later copy the results? When can I clean up my “manual folder” and do I need to make sure that its not named the same for simultaneously running trials?

Thank you!