How to set MultiPV in Komodo?
Moderators: hgm, Rebel, chrisw
-
- Posts: 381
- Joined: Thu Nov 22, 2012 12:20 am
- Location: New Hampshire
How to set MultiPV in Komodo?
I purchased Komodo 13.2.5 this week and I was reading the README file that mentions it beating Stockfish 10 in a test match when in MCTS mode and the MultiPV=6. I wanted to experiment with that with some other engines but I don't see any setting in the Engine Parameters(Fritz 17 GUI) called "MultiPV". Can anyone point me in the right direction?
-
- Posts: 1167
- Joined: Thu Dec 25, 2008 9:07 pm
- Full name: Herbert L
Re: How to set MultiPV in Komodo?
Klick on the "+" Button to the right of the engine name.
+ increased
- decreased
alternatively right click in the Engine window
+ increased
- decreased
alternatively right click in the Engine window
-
- Posts: 5960
- Joined: Sun Jan 10, 2010 6:15 am
- Location: Maryland USA
Re: How to set MultiPV in Komodo?
Assuming the GUI hasn't changed recently, when you load the engine you should see two magnifying glasses with + and -. Just press the + sign five times and it will display the best six moves (and analysis of each) in infinite mode. That is multipv. But I'm not sure if that carries over to running engine matches; it may be that engine matches in Fritz GUI disable multipv. We used our own tester to run these matches.
Komodo rules!
-
- Posts: 550
- Joined: Tue Nov 19, 2019 8:48 pm
- Full name: Alayan Feh
Re: How to set MultiPV in Komodo?
Claims of KMCTS besting Stockfish in MultiPV mode are deceptive.
In MultiPV mode, KMCTS do not devote any more resources than usual to search the 2nd best move, 3rd best move, etc. Yes, it can provide moves and an eval for them, but any move beyond the first one will be searched to a smaller and smaller depth ("depth" might not be the correct technical term for KMCTS, but you get the point). Putting MultiPV on doesn't make the engine search those other moves as much as the first. Leela behaves like KMCTS in this regard.
Meanwhile, in MultiPV mode, Stockfish (and almost all other engines) will search further moves to the same depth as the best. Of course, in most positions, this means exploring irrelevant subtrees, wasting time and polluting the hash table. It's even worse when the badly ranked moves provoke fail-lows. When doing a timed blitz game, where getting more depth is critical, this is a big handicap.
One could easily make Stockfish search subsequent moves beyond the first one at lesser depth, when in MultiPV mode. Simply outputting some move and an eval doesn't cost much by itself. Such a trick offers huge time savings, and at bullet-blitz TC makes the 1st move significantly stronger. When experiments were done around this, there was also a large outcry from people using SF for analysis and not wanting this behaviour, so it never went anywhere, because there is no known good compound quality measure for MultiPV.
TL;DR : With MultiPV=6, KMCTS is only beating Stockfish 10 because it's doing the exact same search as with MultiPV=1 and getting big time odds advantage. The flip-side is that the average ordering/eval of the multiPV moves of KMCTS is inferior to Stockfish 10, but of course when playing a match only the 1st move matters.
In MultiPV mode, KMCTS do not devote any more resources than usual to search the 2nd best move, 3rd best move, etc. Yes, it can provide moves and an eval for them, but any move beyond the first one will be searched to a smaller and smaller depth ("depth" might not be the correct technical term for KMCTS, but you get the point). Putting MultiPV on doesn't make the engine search those other moves as much as the first. Leela behaves like KMCTS in this regard.
Meanwhile, in MultiPV mode, Stockfish (and almost all other engines) will search further moves to the same depth as the best. Of course, in most positions, this means exploring irrelevant subtrees, wasting time and polluting the hash table. It's even worse when the badly ranked moves provoke fail-lows. When doing a timed blitz game, where getting more depth is critical, this is a big handicap.
One could easily make Stockfish search subsequent moves beyond the first one at lesser depth, when in MultiPV mode. Simply outputting some move and an eval doesn't cost much by itself. Such a trick offers huge time savings, and at bullet-blitz TC makes the 1st move significantly stronger. When experiments were done around this, there was also a large outcry from people using SF for analysis and not wanting this behaviour, so it never went anywhere, because there is no known good compound quality measure for MultiPV.
TL;DR : With MultiPV=6, KMCTS is only beating Stockfish 10 because it's doing the exact same search as with MultiPV=1 and getting big time odds advantage. The flip-side is that the average ordering/eval of the multiPV moves of KMCTS is inferior to Stockfish 10, but of course when playing a match only the 1st move matters.
-
- Posts: 4556
- Joined: Tue Jul 03, 2007 4:30 am
Re: How to set MultiPV in Komodo?
I'd be very interested in such a version.Alayan wrote: ↑Sat Jan 11, 2020 6:26 pm One could easily make Stockfish search subsequent moves beyond the first one at lesser depth, when in MultiPV mode. Simply outputting some move and an eval doesn't cost much by itself. Such a trick offers huge time savings, and at bullet-blitz TC makes the 1st move significantly stronger.