[tune] Option --no-cuda is misleading in mnist_pytorch.py example

System information

• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): Ubuntu 16.04
• Ray installed from (source or binary): binary
• Ray version: 0.6.2
• Python version: 3.5
• Exact command to reproduce:

python3 mnist_pytorch.py

Describe the problem

Argument parser’s option --no-cuda which is False by default is misleading as resources_per_trial does not allocate a GPU.

https://github.com/ray-project/ray/blob/eddd60e14e95a2aadb06192bd141d06c68d5f082/python/ray/tune/examples/mnist_pytorch.py#L45-L49

https://github.com/ray-project/ray/blob/eddd60e14e95a2aadb06192bd141d06c68d5f082/python/ray/tune/examples/mnist_pytorch.py#L178-L180

Thanks

[richardliaw]

If you leave “gpu”: 1, the example will not run if Ray does not detect a GPU.

Thanks, Richard

On Tue, Jan 29, 2019 at 2:37 AM vfdev [e-mail] wrote:

I think maybe do something like “gpu”: int(not args.no_cuda), since you don’t want to set it like that when CUDA is disabled.

@richardliaw https://github.com/richardliaw yes, but this is handled inside the trial code:

https://github.com/ray-project/ray/blob/eddd60e14e95a2aadb06192bd141d06c68d5f082/python/ray/tune/examples/mnist_pytorch.py#L62 so we can leave savely “gpu”: 1.

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[vfdev-5]

I think maybe do something like “gpu”: int(not args.no_cuda), since you don’t want to set it like that when CUDA is disabled.

@richardliaw yes, but this is handled inside the trial code: https://github.com/ray-project/ray/blob/eddd60e14e95a2aadb06192bd141d06c68d5f082/python/ray/tune/examples/mnist_pytorch.py#L62 so we can leave savely "gpu": 1.