Hi y_ich san,

First of all, thanks for the apps. I really enjoy using it.
I don't have a powerful PC so having this app really makes my iPad Pro purchase guilt-free.

I wanted to bring to your attention a performance problem when using Katago on iPadOS 15.
I know that iPadOS 15 is still in beta, so I'm not trying to complain about it here.
I'm running the apps with Katago on my 2018 iPad Pro 11 on iPadOS 15 beta 4.
The performance drops significantly for the Katago engine.
When running with the 40b, the number of playouts dropped to an average of 1 per second.
When running with the 10b, the number of playouts dropped to an average of about 35-40 per second.
The performance for the other engine doesn't seem to be affected. I don't really use the other engine so I can't confirm this.
I tried to tweak the settings around but doesn't seem to help in improving the performance.
I also tried to delete and reinstall the app as well.

I hope this helps.
Lastly, I really like the updates visualizing the battlefield. Great work!

jkal san,

Thank you for using the app!
And also thank you to let me know the issue on iPadOS 15.

I will investigate it right after releasing iPadOS 15 or possibly its Release Candidate.

Hi, I would like to know if the app could still work on the new M1 chip Ipad pro? I supposed the A14 new Ipad air would be Ok. Any test about this?

It works great on the M1 iPad!
It's magnitudes faster!
Just amazing!

edit: removed the wrong quote

I quoted the wrong post

The M1 iPad works and is way faster than my other iPad pro.

For an arbitrary mid game position (b40s985 net) :
iPad pro with A12X chip : 1437 playouts with 100 sec thinking time.
iPad pro with M1 chip : 29763 playouts with 100 sec thinking time.

Thanks for the reply！

Thanks.
Does it use the cpu cores or gpu cores or the neural engine cores?
M1X will double the cpu fire cores.
GPU will have 32 cores instead of 8 cores. This will change playlists from 30000 to 120000!!
Neural engine / metal I don’t know but maybe they will double the cores too.

Hi y_ich,

I updated my A13 iPhone 11 Pro to iOS 15, (release version not beta), in preparation for migrating to a new A15 iPhone 13 Pro.

I can confirm jkal's findings that katago has greatly slowed in the new OS. I’m getting maybe 7 visits per second on version 5.15 with the updated b40c256-s1000 engine. Under ios 14 I believe I got 30-40 visits per second.

It’s not just the engine that is slower, the whole app is sluggish, for example, placing a stone can take 1-3 seconds after tapping.

On my older iPad Air with A12 Processor and iOS 14, I’m getting 17 visits per second, and the app feels fine.

I sure hope you can fix the app for iOS 15 soon!

Thank you.

_________________
- Brady
Want to see videos of low-dan mistakes and what to learn from them? Brady's Blunders

The version 5.15.1 has been released.

1. fixed a problem that KataGo ran extremely slowly on iPadOS/iOS 15 depending on devices. As a bonus, you may get performance boost on iPadOS/iOS 15 compared with on iPadOS/iOS 14.

Enjoy!

Thanks y_ich san for the quick updates!
Just updated the apps and KataGo runs a lot faster on my iPad than before.
Great work!

Dear y_ich,

When I updated the app, it repeatedly opened for one second, then crashed. I deleted and reinstalled the app, then restored katago, and that fixed everything.

On the new iPhone 13 pro, I went from 20 visits per second on the last version to nearly 200 visits per second after the fix. That’s approaching decent desktop GPU performance!

Great job, and thanks!

_________________
- Brady
Want to see videos of low-dan mistakes and what to learn from them? Brady's Blunders

On further experimentation, I think there is a problem with batch size. Reinstalling reset batch size to one, and it worked great.

When I reset batch size to four or more it instantly crashes when I start study. Batch size of two is inconsistent, sometimes crashing.

I’ll happily settle for batch size one now.

Thanks and good luck y_ich!

_________________
- Brady
Want to see videos of low-dan mistakes and what to learn from them? Brady's Blunders

wineandgolover san,

Thank you for your helpful information!
I will investigate it soon.

The version 5.15.2 was released.

It fixed a bug that the app crashed on A14/A15 devices with iOS/iPadOS 15 when you use KataGo with batchSize more than (or equal to) 2.

As far as I can tell, the 13 Pro is not taking advantage of its extra gpu core versus the regular 13 for a Master of Go. I tested both side by side, and they alternated being faster by at most 3%.

So unless y_ich can modify the code to leverage the pro's advantage, I don’t recommend buying the pro just for this app.

_________________
- Brady
Want to see videos of low-dan mistakes and what to learn from them? Brady's Blunders

wineandgolover san,

I have no way to know inside A15 and Core ML, but your experiment is quite reasonable.

A15's Neural Engine runs at 15.8FLOPS (though Apple says TOPS instead of FLOPS).
A15's GPU with 5 cores seems run at about 2.5FLOPS with FP16.
It means that 1 core runs at about 0.5FLOPS.

If Core ML uses both Neural Engine and GPU effectively, A15 with 5 cores has total 18.3FLOPS, while A15 with 4 cores has 17.8FLOPS.
The difference is 0.5FLOPS as described above, 0.5/18.3 = 0.027 ~ 3%.

I think that the match with your test is by chance.
Thermal variation may larger than it.

FYI

Thanks y_ich,

I had no idea how much more powerful the neural engine was compared to the gpu. I am glad your app either effectively uses both, or that it’s not a big deal if it isn’t using the gpu. I’m a little surprised the development tools don’t let you dig in and find out more.

Regardless I am delighted with 200 visits per second on the 40 block katago engine. So thank you again!

And I’ll repeat the caveat for others, don’t upgrade to the Pro version of iPhone 13 for this app, the regular is good enough. (The zoom camera was enough reason for me.)

_________________
- Brady
Want to see videos of low-dan mistakes and what to learn from them? Brady's Blunders

Hi, there seems to be a problem with the new ios 15.4. Can‘t put stones on the board.

Pippen san,

Thank you for letting me know it.
I cannot reproduce your issue on my iOS/iPadOS 15.4.
My devices are iPhone SE 2 and iPad Air 4.

Could you send e-mail to me via the app?
The template includes your device/os information.

Thanks.

I just bought a new M1-equipped ipad pro. A Master of Go is amazing. How can I see the nps on the ipad?

_________________
Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21