Piotr Szotkowski about "Bits of ruby"

Ἲtip to RGSoCfriendly confs
♥ eurucamp ♥ JRubyConf ♥ Deccan RubyConf ♥
♥ OTSConf ♥ Madison+ Ruby ♥ BaRuCo ♥
♥ Reject.JS ♥ Strange Loop ♥ RailsClub ♥
♥ EuRuKo ♥ Øredev ♥ ROSSConf ♥
♥ GOTO Conference ♥ dotJS ♥

sooo… who goes where?
Tate Isom Genevieve Ola Arielle
eurucamp ✓ ✓ ✓ ✓
JRubyConf ✓
ROSSConf ✓ ✓
BaRuCo ✓ ✓ ✓
EuRuKo ✓ ✓ ✓
…but how do we track who goes where?
namekeyed hash? confkeyed hash?
how about a logical matrix?

oh of course! (what’s that…?)
a rectangular table of Boolean values
true / false relationship representation
c o n f s = % w ( e u r u c a m p J R u b y C o n f R O S S C o n f B a R u C o E u R u K o )
n a m e s = % w ( T a t e I s o m G e n e v i e v e O l a A r i e l l e )
m a t r i x = [
[ t r u e , t r u e , t r u e , f a l s e , t r u e ] ,
[ t r u e , f a l s e , f a l s e , f a l s e , f a l s e ] ,
[ f a l s e , f a l s e , f a l s e , t r u e , t r u e ] ,
[ f a l s e , t r u e , t r u e , f a l s e , t r u e ] ,
[ t r u e , f a l s e , t r u e , f a l s e , t r u e ] ,
]
m a t r i x [ c o n f s . i n d e x ( ' e u r u c a m p ' ) ] [ n a m e s . i n d e x ( ' T a t e ' ) ] # = > t r u e
m a t r i x [ c o n f s . i n d e x ( ' R O S S C o n f ' ) ] [ n a m e s . i n d e x ( ' G e n e v i e v e ' ) ] # = > f a l s e

but that’s not very efficient
every conference adds a row
every participant adds a column
confs.size×(names.sizeBools+1Array)+1Array
how about using zeroes and ones instead?

logical matrix
m a t r i x = [
]

bit matrix
m a t r i x = [
[ 1 , 1 , 1 , 0 , 1 ] ,
[ 1 , 0 , 0 , 0 , 0 ] ,
[ 0 , 0 , 0 , 1 , 1 ] ,
[ 0 , 1 , 1 , 0 , 1 ] ,
[ 1 , 0 , 1 , 0 , 1 ] ,
]

bit matrix
m a t r i x = [
0 b 1 1 1 0 1 ,
0 b 1 0 0 0 0 ,
0 b 0 0 0 1 1 ,
0 b 0 1 1 0 1 ,
0 b 1 0 1 0 1 ,
]
m a t r i x = [ 2 9 , 1 6 , 3 , 1 3 , 2 1 ]

how much better?
names.sizeFixnums+1Array → 1Fixnum
Fixnums go up to 2E62-1
…that’s 4611686018427387903
…that’s 4_611_686_018_427_387_903
I’m better at estimating things
than probably 40 or 50 billion people.
— Randy Tayler
…that’s over four quintillion

but how do we query it?
n a m e s = % w ( T a t e I s o m G e n e v i e v e O l a A r i e l l e )
m a t r i x = [
]
m a t r i x [ c o n f s . i n d e x ( ' e u r u c a m p ' ) ] [ n a m e s . i n d e x ( ' T a t e ' ) ] # = > t r u e
m a t r i x [ c o n f s . i n d e x ( ' R O S S C o n f ' ) ] [ n a m e s . i n d e x ( ' G e n e v i e v e ' ) ] # = > f a l s e

Integer#[]
2 9 = = 0 b 1 1 1 0 1 # = > t r u e
2 9 [ 0 ] # = > 1
2 9 [ 1 ] # = > 0
2 9 [ 2 ] # = > 1
return the nth least significant bit
n a m e s = % w ( T a t e I s o m G e n e v i e v e O l a A r i e l l e ) . r e v e r s e
m a t r i x = [ 0 b 1 1 1 0 1 , 0 b 1 0 0 0 0 , 0 b 0 0 0 1 1 , 0 b 0 1 1 0 1 , 0 b 1 0 1 0 1 ]
m a t r i x [ c o n f s . i n d e x ( ' e u r u c a m p ' ) ] [ n a m e s . i n d e x ( ' T a t e ' ) ] # = > 1
m a t r i x [ c o n f s . i n d e x ( ' R O S S C o n f ' ) ] [ n a m e s . i n d e x ( ' G e n e v i e v e ' ) ] # = > 0

so… how many go to each conf?
e u r u c a m p = m a t r i x [ c o n f s . i n d e x ( ' e u r u c a m p ' ) ] # = > [ t r u e , t r u e , t r u e , f a l s e , t r u e ]
e u r u c a m p . c o u n t ( t r u e ) # = > 4
e u r u c a m p = m a t r i x [ c o n f s . i n d e x ( ' e u r u c a m p ' ) ] # = > 0 b 1 1 1 0 1
e u r u c a m p . t o _ s ( 2 ) . c o u n t ( ' 1 ' ) # = > 4
number of ones in a binary representation
‘population count’
but to_s(2).count('1') is not very efficient

let’s freedompatch Integer
c l a s s I n t e g e r
d e f p o p c o u n t _ t o _ s
t o _ s ( 2 ) . c o u n t ( ' 1 ' )
e n d
d e f p o p c o u n t _ c o n t _ s h i f t
c o u n t = 0
n u m b e r = s e l f
u n t i l n u m b e r = = 0
c o u n t + = n u m b e r & 1
n u m b e r > > = 1
e n d
c o u n t
e n d
e n d

d e f p o p c o u n t _ b i t _ e l i m
c o u n t = 0
w h i l e n u m b e r ! = 0
n u m b e r & = n u m b e r - 1
c o u n t + = 1
e n d
c o u n t
e n d
d e f p o p c o u n t _ p r o g _ s h i f t
n u m b e r - = ( n u m b e r > > 1 ) & 0 x 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
n u m b e r = ( n u m b e r & 0 x 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 ) + ( ( n u m b e r > > 2 ) & 0 x 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 )
n u m b e r = ( n u m b e r + ( n u m b e r > > 4 ) ) & 0 x 0 f 0 f 0 f 0 f 0 f 0 f 0 f 0 f
n u m b e r = ( n u m b e r + ( n u m b e r > > 8 ) ) & 0 x 0 0 f f 0 0 f f 0 0 f f 0 0 f f
n u m b e r = ( n u m b e r + ( n u m b e r > > 1 6 ) ) & 0 x 0 0 0 0 f f f f 0 0 0 0 f f f f
n u m b e r + = n u m b e r > > 3 2
( n u m b e r + ( n u m b e r > > 6 4 ) ) & 0 x f f
e n d
e n d

r e q u i r e ' i n l i n e '
i n l i n e d o | b u i l d e r |
b u i l d e r . c '
i n t p o p c o u n t _ b i t _ e l i m _ c ( ) {
l o n g n u m b e r = N U M 2 L O N G ( s e l f ) ;
i n t c o u n t ;
f o r ( c o u n t = 0 ; n u m b e r ; c o u n t + + ) n u m b e r & = n u m b e r - 1 ;
r e t u r n c o u n t ;
}
'
e n d
i n l i n e d o | b u i l d e r |
b u i l d e r . c '
i n t p o p c o u n t _ b u i l t i n ( ) {
r e t u r n _ _ b u i l t i n _ p o p c o u n t l ( N U M 2 L O N G ( s e l f ) ) ;
}
'
e n d
e n d

P O P C O U N T _ C A C H E = ( 0 x 0 0 0 0 . . 0 x f f f f ) . m a p { | n u m b e r | n u m b e r . t o _ s ( 2 ) . c o u n t ( ' 1 ' ) }
d e f p o p c o u n t _ c a c h e d
P O P C O U N T _ C A C H E [ s e l f & 0 x f f f f ] +
P O P C O U N T _ C A C H E [ s e l f > > 1 6 & 0 x f f f f ] +
P O P C O U N T _ C A C H E [ s e l f > > 3 2 & 0 x f f f f ] +
P O P C O U N T _ C A C H E [ s e l f > > 4 8 ]
e n d
e n d

r e q u i r e ' b e n c h m a r k / i p s '
m e t h o d s = I n t e g e r . i n s t a n c e _ m e t h o d s . g r e p ( / ^ p o p c o u n t _ / )
n u m b e r s = A r r a y . n e w ( 1 _ 0 0 0 ) { r a n d ( 0 . . . ( 2 * * 6 2 - 1 ) ) }
f a i l ' o o p s ' u n l e s s m e t h o d s . m a p { | m e t h | n u m b e r s . m a p ( & m e t h ) } . u n i q . s i z e = = 1
B e n c h m a r k . i p s d o | b e n c h |
m e t h o d s . e a c h d o | m e t h |
b e n c h . r e p o r t ( m e t h [ 9 . . - 1 ] ) { n u m b e r s . m a p ( & m e t h ) }
e n d
b e n c h . c o m p a r e !
e n d

W a r m i n g u p - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
b i t _ e l i m 5 3 . 0 0 0 i / 1 0 0 m s
c a c h e d 2 7 6 . 0 0 0 i / 1 0 0 m s
c o n t _ s h i f t 1 7 . 0 0 0 i / 1 0 0 m s
p r o g _ s h i f t 1 3 1 . 0 0 0 i / 1 0 0 m s
t o _ s 6 9 . 0 0 0 i / 1 0 0 m s
b i t _ e l i m _ c 1 . 0 9 8 k i / 1 0 0 m s
b u i l t i n 1 . 4 5 3 k i / 1 0 0 m s
C a l c u l a t i n g - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
b i t _ e l i m 5 4 1 . 1 2 7 ( ± 0 . 4 % ) i / s - 2 . 7 5 6 k
c a c h e d 2 . 8 0 6 k ( ± 0 . 3 % ) i / s - 1 4 . 0 7 6 k
c o n t _ s h i f t 1 8 9 . 9 2 1 ( ± 1 . 1 % ) i / s - 9 5 2 . 0 0 0
p r o g _ s h i f t 1 . 5 9 6 k ( ± 0 . 3 % ) i / s - 7 . 9 9 1 k
t o _ s 6 9 5 . 5 2 8 ( ± 0 . 4 % ) i / s - 3 . 5 1 9 k
b i t _ e l i m _ c 1 1 . 1 7 2 k ( ± 1 . 4 % ) i / s - 5 5 . 9 9 8 k
b u i l t i n 1 4 . 6 6 1 k ( ± 1 . 1 % ) i / s - 7 4 . 1 0 3 k
C o m p a r i s o n :
b u i l t i n : 1 4 6 6 1 . 1 i / s
b i t _ e l i m _ c : 1 1 1 7 1 . 8 i / s - 1 . 3 1 x s l o w e r
c a c h e d : 2 8 0 5 . 6 i / s - 5 . 2 3 x s l o w e r
p r o g _ s h i f t : 1 5 9 5 . 7 i / s - 9 . 1 9 x s l o w e r
t o _ s : 6 9 5 . 5 i / s - 2 1 . 0 8 x s l o w e r
b i t _ e l i m : 5 4 1 . 1 i / s - 2 7 . 0 9 x s l o w e r
c o n t _ s h i f t : 1 8 9 . 9 i / s - 7 7 . 2 0 x s l o w e r

Tate Isom Genevieve Ola Arielle
eurucamp ✓ ✓ ✓ ✓
JRubyConf ✓
ROSSConf ✓ ✓
BaRuCo ✓ ✓ ✓
EuRuKo ✓ ✓ ✓

thanks!
@chastell
talks.chastell.net

Piotr Szotkowski about "Bits of ruby"

Recommended

Recommended

More Related Content

What's hot

What's hot (8)

Similar to Piotr Szotkowski about "Bits of ruby"

Similar to Piotr Szotkowski about "Bits of ruby" (20)

More from Pivorak MeetUp

More from Pivorak MeetUp (20)

Recently uploaded

Recently uploaded (20)

Piotr Szotkowski about "Bits of ruby"