Make new picotutor behave like the existing one, help needed!

[Johan Sjöblom]

Hi.

I need help to make the new picotutor behave exactly the same as the existing one. The new chess library uses centipawns. I don't know what unit the existing one is using, but its not centipawns so we are forced to update all picotutor parameters.

In the attached Excel and PDF you can see the values on page 1 marked in yellow. I think the values for ?? and ? could be 150 and 50 cp respectively as that is actually mentioned in the original Cambridge paper and they seem reasonable.... However; those two values have a different conversion ratio which changes the behaviour. If we want the same behaviour as the existing one we have to settle on a ratio value.

I would propose a ratio of 33.3, but if someone knows the unit of the old chess library maybe we can find an exact ratio from that to centipawns?

Comments, suggestions, ideas?

Best Regards, Johan

PS. I collected the Cambridge formulas into these documents as well.

[Johan Sjöblom]

It seems the old code is simply using centipawns divided by 100, so that would mean that I should use a factor of 100...

I should therefore change the constants according to these new values to make it similar to the existing one.

BR, Johan

[Johan Sjöblom]

I have now updated the new picochess 4. main branch to match the existing picotutor 3 settings...

Brave testers are welcome to test :-)

https://github.com/JohanSjoblom/picochess

[Johan Sjöblom]

I updated the documentation of the Picotutor "Cambridge" system to evaluate moves to !!,!,!? and ?!. I wonder if there is any newer study on this issue to be found... And I am also curious to what chess.com possibly uses. I think the picochess tutor is quite unique at the moment but it has potential to be even better.

Anyway, heres the updated documentation in case someone wants to contribute.

BR, Johan

[Johan Sjöblom]

If I would have done this update correct I would have put the newer PDF file as well :-) Anyway, here goes:

I also found someone else who recently started a similar discussion on lichess 23rd of March.

https://lichess.org/@/NDpatzer/blog/science-of-chess-what-makes-a-move-seem-brilliant/wtFdMXzO

Basically there is the same idea, simplest being looking for a high gradient from low-ply to max-ply.

BR, Johan

[Johan Sjöblom]

The new picotutor in V4 should now work as in V3. To make it easier to test I added the evaluations like !! to be stored in the game PGN file when the game ends.

[Dirk]

Cool - thanks Johan.

I will check in a few weeks and test…

Dirk

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[Johan Sjöblom]

There are now more things to test... and we need more brave testers for the new Pico V4.

As there is no image made yet you need to have some skills. Not much, but some basic linux commands and the ability to create your own standard PI stock image using the Raspberry PI Imager program. Follow the instructions in the readme on

https://github.com/JohanSjoblom/picochess?tab=readme-ov-file#readme

You can comment on your test results on the issues section on the github above (preferred) or you can of course just comment or ask for help here in this discussion group.

I made a new feature to make Picotutor testing more fun. There are plenty of software out there that can analyse a program for you, but in Picochess the Picotutor is quite unique in its way to evaluate moves with !!, ! etc. In order to take advantage of that I created a feature branch that allows Picotutor to work in Hint/ANALYSIS mode. This means that you can play through a game making moves for both sides, and Picotutor will be watching the game and evaluating every move. You can pick any famous game from the internet, play it through in Hint mode, and see if Picotutor makes the same comments as the expert humans have done. Of course you can play through your own games as well. This feature was quite tricky to make actually, and required a lot of changes to picotutor. But I have taken great care to make sure it works like in V3 as the primary target is first to get all same functions and features as in V3.

To test this new feature you need a little bit more skill... Instead of the normal git pull you need to pull the test branch like this:

cd /opt/picochess

git pull issue30-picotutor-hintmode

Some git basics: To get back to normal master branch if you want to test without this new Hint feature do:

git checkout master   .... or

git switch master

So testing a branch requires a little bit of skill.

It would be best to test this branch as everything that works in master branch should work here, and after I have completed my own testing of this branch I will merge this issue30-picotutor-hintmode branch and after that everyone will get it. But first we need to test it.

BR, Johan

[Johan Sjöblom]

Sorry, a detail, but to correctly get a test branch the proper command is of course not git pull but git checkout branchname like this:

git checkout issue30-picotutor-hintmode

Notice the checkout, not pull. This can be done after cloning, or after having followed the instructions.

[Johan Sjöblom]

Sorry for many posts on this issue. To make it simpler I merged this new feature to main branch. There is only one version to test now and that is the one you get by a normal installation by following the readme instructions

https://github.com/JohanSjoblom/picochess?tab=readme-ov-file#readme

I tested the basics on my DGT board. I will test it more myself during Easter...

BR, Johan