Effective hand strength algorithm: Difference between revisions

Revision as of 18:58, 5 October 2022

Latest revision as of 09:57, 21 July 2024

(11 intermediate revisions by 7 users not shown)

Line 1:

{{Short description|Poker algorithm published in 1998}}

{{More citations needed|date=April 2013}}

{{Orphan|date=February 2013}}

'''Effective Hand Strength (EHS)''' is a poker algorithm conceived by [[computer scientists]] [[Darse Billings]], [[Denis Papp]], [[Jonathan Schaeffer]] and [[Duane Szafron]] that was published for the first time in the {{cite journal | last1 = research paper | url=http://www.cs.virginia.edu/~evans/poker/wp-content/uploads/2011/02/opponent_modeling_in_poker_billings.pdf | title=Opponent Modeling in Poker | journal=AAAI-98 Proceedings| year = 1998}}

It has since then been considered as a reference in the realm of poker artificial intelligence and has been the basis of further research such as:

* {{cite journal |last1=Rubin |first1=Jonathan |last2=Watson |first2=Ian |title=Computer poker: A review |journal=Artificial Intelligence |date=April 2011 |volume=175 |issue=5-65–6 |pages=958–987 | url= http://www.cs.auckland.ac.nz/~ian/papers/AIJournal.pdf |doi=10.1016/j.artint.2010.12.005}}

* {{cite thesis |last=Schuijtvlot |first = Erwin | url= http://www.few.vu.nl/en/Images/werkstuk-schuijtvlot_tcm39-225501.pdf |archive-url=https://web.archive.org/web/20190522091814/https://beta.vu.nl/nl/Images/werkstuk-schuijtvlot_tcm235-225501.pdf |archive-date=2019-05-22| title = Application of AI in poker |type=Master's thesis |publisher=Vrije Universiteit Amsterdam | year = 2011 | pages = 12–13}}

* {{citeCite journalbook |url=https://link.springer.com/book/10.1007/978-3-540-88190-2 |title = Advances in artificial intelligence – SBIA 2008 : 19th Brazilian Symposium on Artificial Intelligence, Salvador,- Brazil, October 26–30,SBIA 2008 ; proceedings | year = 2008 | pages=85–86 |language=en 85–86|doi=10.1007/978-3-540-88190-2}}

== Algorithm ==

Line 28 ⟶ 27:

ahead = tied = behind = 0

ourrank = Rank(ourcards, boardcards)

for each case(oppcards) {

opprank = Rank(oppcards, boardcards)

Line 34:

else behind += 1

}

handstrength = (ahead + tied / 2) / (ahead + tied + behind)

return handstrength

}

Line 42 ⟶ 44:

<pre>

HandPotential(ourcards, boardcards) {

// Hand potential array, each index represents ahead, tied, and behind

integer array HP[3][3] // initialize to 0

integer array HPTotal[3] // initialize to 0

ourrank = Rank(ourcards, boardcards)

// Consider all two card combinations of the remaining cards for the opponent

for each case(oppcards) {

Line 54 ⟶ 57:

else index = behind

HPTotal[index] += 1

// All possible board cards to come

for each case(turn, river) {

Line 65 ⟶ 69:

}

}

// Ppot: were behind but moved ahead

Ppot = (HP[behind][ahead] + HP[behind][tied] / 2 + HP[tied][ahead] / 2) / (HPTotal[behind] + HPTotal[tied])

// Npot: were ahead but fell behind

Npot = (HP[ahead][behind] + HP[tied][behind] / 2 + HP[ahead][tied] / 2) / (HPTotal[ahead] + HPTotal[tied])

return [ Ppot, Npot ]

}

Line 77 ⟶ 83:

Given the complexity of the algorithm, it can not be computed manually and has to be used in an Artificial Intelligence context.

== References ==

{{Reflist}}

[[Category:Poker probability]]