04 May 2015

What Ticks Off Engine Users? (Part III)

In 'What Ticks Off Engine Users?' Part I, we saw an inexperienced chess engine user ('MacUser') struggling to use Komodo, one of the world's top chess engines. Despite the support of an experienced Komodo Help team, we saw in Part II that MacUser finally concluded that he was unable to use the product.

I noted at the end of Part II, 'the discussion contains useful information that is not widely known', so let's recap that information. At the beginning of the discussion between MacUser and Komodo Help, I had already noted,

MacUser has confused the engine he bought from Komodo with the GUI he needs to operate the engine.

Chess engines are largely in the realm of the hobbyist, and it's already obvious that MacUser is not a hobbyist. When Komodo Help asks later,

K: Are you trying to play games between the engines, or just analyzing games?

We can assume that MacUser is 'just analyzing games', where he is already over his head. He has apparently been using a standalone Hiarcs setup where the GUI and the engine are integrated, and has never realized that they can be separate components. There is a helpful article at Serverchess.com, Advanced Chess - Hints to Get Started, that begins,

Players new to the world of engine-assisted play are often puzzled to find no published "how to" articles. Unlike traditional chess, there are no teaching sites, instruction books or recommended reading lists, not even suggestions on what equipment to purchase or how to use it in "advanced chess".

One reason for this is that the field is constantly evolving. What was true yesterday is no longer true today and what is true today will not be true tomorrow. Another reason is that chess engine hobbyists are not as interested in writing as they are in tinkering with their engine setups. The 'Advanced Chess' article tries to plug this gap, largely succeeds, and offers a list of GUIs (with links): Arena, Aquarium, Chessbase, Chessbase Reader, ChessPad, SCID, and Tarrasch.

Unfortunately, most of these are not available to MacUser, whose choice is severely limited. After learning that he is forced to use a GUI, MacUser struggles to install an engine.

M: I have been trying to upload it into the HIARCS GUI but there is no setting there for "LMR", the threads cannot be adjusted, and your guidance for table base settings is inadequate on this GUI.

The phrase 'upload it into the GUI' suggests that MacUser is not familiar with the file system on his Mac and he later struggles with the same concept in Scid. As for the engine configuration parameters, we can assume that MacUser is clueless. Komodo Help seems to have made the same assumption.

K: Perhaps you have to scroll down to see the remaining engine settings lke LMR, Syzygy settings and Threads?

As for the values of the parameters, later there is another interesting exchange. The first is on the setting of threads. It leads to a discussion of ply.

M: Komodo on the HIARCS GUI is not running well, much slower and weaker than the HIARCS, it hasn’t got over 21 ply yet.

K: With an i7, which has 4 "cores", you should set the number of "threads", which is an engine setting, to 4. [...] Note you cannot really directly compare search depth between programs, since some programs (like Stockfish) reduce the search a lot, while other like Komodo extend critical lines a lot. A better comparison is the length of the principal variation displayed. As for strength, on the same hardware, Komodo 8 is about 230 (or more) Elo stronger than Hiarcs 14.

It's safe to assume that MacUser has no idea why cores and threads are important. As for the importance of ply, he first notes, 'plys in the 20s are a joke, we live in a 40 ply world' (an assumption also made in the 'Advanced Chess' article referenced above), then continues,

M: Komodo was default set at one thread. I have changed that to your recommended four. The HIARCS programs are set at eight threads. Komodo still seems to be slow.

K: In the TCEC (which many consider the world championship), Komodo was searching to depths of typically 27 or 28. Komodo won season 7 against the "higher depth" Stockfish. But as I said, compare PV length and you will see Komodo searches much deeper that its iteration depth. [...] I do not know why Hiarcs is using eight. There is something called hyperthreading which uses two threads per CPU core. We do not think this helps Komodo. Just match threads to actual cores for Komodo.

Let's recap those steps: (1) choosing a GUI, (2) adding an engine to the GUI, (3) configuring the engine, (4) understanding engine metrics. Is it any wonder that MacUser ultimately abandoned his quest to use a new chess engine?

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