documentation on UCI options

[masterkni6]

any place on descriptions of UCI options? the one on github is missing alot and --help in commandline does nothing.
Im trying to use my second GPU and i see First_Device_ID but not sure if thats the right option. Thanks and sorry for all the issues

[QueensGambit]

No, worries. I think a lot of people have similar problems or questions and benefit from your issues.

The UCI Options are documented in the Wiki pages:

• https://github.com/QueensGambit/CrazyAra/wiki/Engine-settings

However, the documentation is currently out-of sync with the current release.
I'll update it soon.

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I agree that more info on how to use multiple GPU would be nice.
Multi-GPU support has already been integreated in (#33).

The option Device_ID has been replaced by First_Device_ID and Last_Device_ID.
This way CrazyAra will use all GPUs with a device id of:
First_Device_ID <= Device ID <= Last_Device_ID.
All GPUs use the same precision backend (e.g. float32, float16, int8) and batch size.

A trt file will then be generated for each GPU device index separately.
This allows to use multiple different GPUs (e.g. I am using a GTX1080ti and RTX 2070 OC at the moment).

However, there is the following limitation right now.
If you have a GPU cluster for example and want to use devices 1 and 3, but not device 2, then this is not possible, as you are only able to select a given range of devices.
I wasn't sure if these lacking features are necessary in practice.

[masterkni6]

im just using each GPU for their own exclusive matches. However setting First and Last device ID to 1 crashes. Second GPU works with lc0 so not sure if there is a problem

[QueensGambit]

You need to run the isready process again, preferably from the command line, if you want to use a different GPU.
However, this needs to be done only once.

setoption name First_Device_ID value 1
setoption name Last_Device_ID value 1
isready

For more information see Command-Line-Usage.

[masterkni6]

im using cutechess so dont think that is an option. Oh is it to generate another trt file?

[QueensGambit]

Oh is it to generate another trt file?

Correct.
As you may use two different types of GPUs, they require a different trt-file.

[masterkni6]

awesome, thanks

[QueensGambit]

The documentation on the UCI options has been updated in the wiki-pages.

Adding an additional --help flag is a nice enhancement for future releases.