Forum Archive :
Cube Handling in Races
What's your favorite formula?
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What's your favorite formula?
13 14 15 16 17 18 19 20 21 22 23 24
+---+---+---+---+---+---+---+---+---+---+---+---+---+
| O | | O O O O O | 56 pips
| | | O O O O |
| | | O O O |
| | | O |
| | | O |
| | | | +---+
| | | | | 1 |
| | | | +---+
| | | |
| | | X |
| | | X X |
| | | X X X X X X |
| | | X X X X X X | 59 pips
+---+---+---+---+---+---+---+---+---+---+---+---+---+
12 11 10 9 8 7 6 5 4 3 2 1
X on roll. Cube action?
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Stick writes:
I would heavily prefer EPC to Keith in this type of situation in general.
EPC for blue I know as a reference position so there is no question that I
have that right. As for the opponent, I also have a similar high
wastage/gapped reference position that I believe will get me close to the
correct amount of wastage. Both formulas bottom line is the same, ND/T,
though the double is not far off.
- Estimate both players' epcs. In Timothy's example X's epc would be 68.5
(59 + 9.5 of wastage, flat position wastes 10 pips and I know this
specific one from reference). O's epc is ~71. (56 + 15 in wastage)
- Figure out the # of rolls to go by dividing the leader's/cubing player's
epc by 7. For instance in Timothy's example shown below Blue's epc is
68.5/7 = ~10.
- The point of last take for the trailer is equal to the number of rolls to
go (10) minus three. So the PoLT is 10-3 or 7 effective pips.
- You can send an initial cube when you're within 2 effective pips of his
point of last take and a recube when you are within 1 effective pips. We
know the PoLT = 75.5 (68.5 + 7) so to double our opponent would need to
have an epc of 73.5 or more.
For everyone who kind of read that and glossed over it I promise it isn't
as complicated as it comes off if you take a minute to understand what at
first looks like gobblety gook.
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Taper_Mike writes:
Keith Count
Player on roll
59 Raw pip count
+2 One extra checker on 1pt
+1 One extra checker on 2pt
---
62 Subtotal
+8 Add 1/7 (rounding down)
---
70 Keith Count
Opponent
56 Raw pip count
+4 Two extra checkers on 1pt
+1 One extra checker on 2pt
+2 Two extra checkers on 3pt
+1 Gap on 4pt
---
64 Keith Count
Because 70 exceeds 64 by more than 4, the Keith Count rates this as a "no-
double."
- - - - - - -
Market Losers
White will be fine so long as he can bear off a checker next turn. Fine,
that is, so far as a take is concerned. That means he needs to roll a 5 or
6 (except 54 64), or else roll any doublet except 11. But look what happens
when he throws 42 or one of the 9 numbers totaling 5 pips or less. Then we
are suddenly in a 7.5-roll-versus-8-roll position, with the leader Blue on
roll. That is "double-pass" territory. So, at least 30% of the time, Blue
will lose his market.
This is a conservative estimate. Blue could also roll big doublets, and
lose his market that way.
With so many market losers, it is clear that this is a double.
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Timothy Chow writes:
I was playing against XG and took my time over this decision. I couldn't
see a good way of estimating White's EPC. Keith Count gave a very clear ND,
so I took a roll. I was quite surprised that the computer thought I had
erred. The discussion here has been very helpful; thanks.
Rollout (324 games with VR, moves and cube decisions 4 ply):
X's winning chances: 71.84%
Equity (no double): +0.671 (-0.032)
Equity (double/take): +0.703
Equity (double/drop): +1.000
Best Cube action: Double / Take
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Cube Handling in Races
- Bower's modified Thorp count (Chuck Bower, July 1997)
- Calculating winning chances (Raccoon, Jan 2007)
- Calculating winning chances (OpenWheel+, Nov 2005)
- Doubling formulas (Michael J. Zehr, Jan 1995)
- Doubling in a long race (Brian Sheppard, Feb 1998)
- EPC example (adambulldog+, Jan 2011)
- EPC example: stack and straggler (neilkaz+, Jan 2009)
- EPC examples: stack and straggler (Carlo Melzi+, Dec 2008)
- Effective pipcount (Douglas Zare, Sept 2003)
- Effective pipcount and type of position (Douglas Zare, Jan 2004)
- Kleinman count (Øystein Johansen+, Feb 2001)
- Kleinman count (André Nicoulin, Sept 1998)
- Kleinman count (Chuck Bower, Mar 1998)
- Lamford's race forumla (Michael Schell, Aug 2001)
- N-roll vs n-roll bearoff (David Rubin+, July 2008)
- N-roll vs n-roll bearoff (Gregg Cattanach, Nov 2002)
- N-roll vs n-roll bearoff (Chuck Bower+, Dec 1997)
- Near end of game (Daniel Murphy, Mar 1997)
- Near end of game (David Montgomery, Feb 1997)
- Near end of game (Ron Karr, Feb 1997)
- One checker model (Kit Woolsey+, Feb 1998)
- Pip count percentage (Jeff Mogath+, Feb 2001)
- Pip-count formulas (Tom Keith+, June 2004)
- Thorp count (Chuck Bower, Jan 1997)
- Thorp count (Simon Woodhead, Sept 1991)
- Thorp count questions (Chuck Bower, Sept 1999)
- Value of a pip (Tom Keith, June 2004)
- Ward's racing formula (Marty Storer, Jan 1992)
- What's your favorite formula? (Timothy Chow+, Aug 2012)
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