Where my numbers vary is
6!:2 'HV {~ hands'
0.453486
hands1 =. {. hands
6!:2 'HV {~ hands1'
0.0381164
Your lookup from hands seems about 3x slower than mine.
6!:2 '(HV {~ +)/ hands'
0.911518
That's what I expected.
Henry Rich
On 1/4/2016 4:46 AM, Ryan Eckbo wrote:
I ran some tests:
$hands
8 10000000
$HV
32487834
hands1=. {.hands
6!:2'HV {~ hands1'
0.105281
6!:2'HV {"1~ hands' NB. slow!
2.33324
6!:2'+/ hands'
0.434148
6!:2'([+])/ hands' NB. 4 times slower than +/
1.69306
6!:2'(HV {~ +)/ hands'
3.1239
6!:2'(HV {~ [+])/ hands' NB. [+] makes no difference here
3.0128
6!:2'{. hands'
0.114971
I don't understand the J runtime well but it seems all these bits add up?
On 4 Jan 2016, at 14:40, Henry Rich wrote:
This time seems way too high to me.
When I time a + a on 1e7 ints, I get about .03 sec. When I time a {
i. 100 on 1e7 ints, I get about the same.
This program should be about 14 of those, and thus take around 0.5
sec. 3 sec is way too high.
Can you dig into this and see where the time is going?
Henry Rich
On 1/3/2016 9:05 PM, Ryan Eckbo wrote:
Henry's idea made the computation 10 times faster:
hands=. |: 53,.~ >:(1e7#7)?52
6!:2 'handvalues=. (HR {~ +)/ hands'
3.08429
HANDTYPE=: <;._2 [0 : 0
BAD
High Card
One Pair
Two Pair
Trips
Straight
Flush
Full House
Quads
Straight Flush
)
HANDTYPE {~ _12 (33 b.) 10 {. handvalues NB. right shift 12 bits
to get hand type id
┌────────┬────────┬────────┬────────┬────────┬────────┬────────┬─────────┬─────┬────────┐
│Two Pair│One Pair│One Pair│Two Pair│One Pair│One Pair│One Pair│High
Card│Flush│One Pair│
└────────┴────────┴────────┴────────┴────────┴────────┴────────┴─────────┴─────┴────────┘
By the way you can also use this method to evaluate 5 or 6 card hands:
hr7=: (HR {~ +)/@:(,&53)
hr5or6=: HR {~ hr7
I think this should be fast enough for my purposes, if not I'll
either write a C api
as Raul suggested or test other evaluator implementations (like
http://suffe.cool/poker/evaluator.html,
which is actually used to construct the HR lookup table, and is fast
for 5 card evaluations -- although
I can't imagine it being faster than a lookup table).
Here's an interesting fact: there are 2.5 millions 5 card hand
combinations but only 7462 distinct hand values.
The hand values returned by HR aren't in this range but they do
guarantee that if HR[hand1_idx] > HR[hand2_idx]
then hand1 beats hand2.
Thanks for the help!
Ryan
On 3 Jan 2016, at 14:56, Ryan Eckbo wrote:
I've implemented the twoplustwo 7 card poker hand evaluator[1] in J
but it's
slower than I expected. The evaluator works by accepting an array
of 7
integers between 1 and 52, representing a 7 card hand, and uses
them as indices
in a lookup table, which returns the best 5 card hand's rank
value. Here's the
C code that does this (HR is the lookup table):
int LookupHand(int* pCards)
{
int p = HR[53 + *pCards++];
p = HR[p + *pCards++];
p = HR[p + *pCards++];
p = HR[p + *pCards++];
p = HR[p + *pCards++];
p = HR[p + *pCards++];
return HR[p + *pCards++];
}
My J version is:
hr=: (HR {~ +)/@:(,&53) NB. hr 1 5 9 12 20 25 42
This is one of the fastest evaluators out there, for example a
javascript version
can run at 20 million evaluations per second. My J version takes
30 seconds
to evaluate just 10 million hands:
hands=. 53,.~ >: ? 1e7 7 $ 52 NB. 10 million hands, with initial
index 53 added
6!:2 '(HR {~ +)/"1 hands' NB. 32.14 sec on a 2.8GHz Mac
I wonder why it's slow and if there's a way to make it faster?
[1]
https://github.com/christophschmalhofer/poker/blob/master/XPokerEval/XPokerEval.TwoPlusTwo.Test/test.cpp
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