Answering this SO question this SO question recently, I've developed the following code (based on a well-known Active Code recipe, as discussed here):
wheel = [2,4,2,4,6,2,6,4,2,4,6,6,2,6,4,2,6,4,6,8,4,2,4,2,
4,8,6,4,6,2,4,6,2,6,6,4,2,4,6,2,6,4,2,4,2,10,2,10]
wsize = 48
def primes():
yield from (2, 3, 5, 7)
yield from wsieve()
def wsieve(): # wheel-sieve, by Will Ness. cf. ideone.com/WFv4f
yield 11 # cf. httphttps://stackoverflow.com/a/10733621/849891
mults = {} # httphttps://stackoverflow.com/a/19391111/849891
ps = wsieve()
p = next(ps)
psq, c, i = p*p, 11, 0 # 13 = 11 + wheel[0]
cbase, ibase = 11, 0
while True:
c += wheel[i] ; i = (i+1) % wsize # 17 = 13 + wheel[1]
if c in mults:
(j,pbase) = mults.pop(c) # add(mults, NEXT c, j, pbase)
elif c < psq:
yield c ; continue
else: # (c==psq)
while not cbase == p:
cbase += wheel[ibase]
ibase = (ibase+1) % wsize # ibase - initial offset into wheel, for p
j, pbase = ibase, p # add(mults, NEXT c, ibase, p)
p = next(ps) ; psq = p*p
m = c + pbase*wheel[j] ; j = (j+1) % wsize # mults(p) = map (*p)
while m in mults: # roll(wheel,ibase,p)
m += pbase*wheel[j] ; j = (j+1) % wsize
mults[m] = (j,pbase)
In particular, I have the rolled wheel streams inlined, using different variables for different "objects". It seems all over the place; is there a way to encapsulate it into a bona fide object, without loosing performance? (last time last time when I used functions for some encapsulation, efficiency suffered efficiency suffered).
Answering this SO question recently, I've developed the following code (based on a well-known Active Code recipe, as discussed here):
wheel = [2,4,2,4,6,2,6,4,2,4,6,6,2,6,4,2,6,4,6,8,4,2,4,2,
4,8,6,4,6,2,4,6,2,6,6,4,2,4,6,2,6,4,2,4,2,10,2,10]
wsize = 48
def primes():
yield from (2, 3, 5, 7)
yield from wsieve()
def wsieve(): # wheel-sieve, by Will Ness. cf. ideone.com/WFv4f
yield 11 # cf. http://stackoverflow.com/a/10733621/849891
mults = {} # http://stackoverflow.com/a/19391111/849891
ps = wsieve()
p = next(ps)
psq, c, i = p*p, 11, 0 # 13 = 11 + wheel[0]
cbase, ibase = 11, 0
while True:
c += wheel[i] ; i = (i+1) % wsize # 17 = 13 + wheel[1]
if c in mults:
(j,pbase) = mults.pop(c) # add(mults, NEXT c, j, pbase)
elif c < psq:
yield c ; continue
else: # (c==psq)
while not cbase == p:
cbase += wheel[ibase]
ibase = (ibase+1) % wsize # ibase - initial offset into wheel, for p
j, pbase = ibase, p # add(mults, NEXT c, ibase, p)
p = next(ps) ; psq = p*p
m = c + pbase*wheel[j] ; j = (j+1) % wsize # mults(p) = map (*p)
while m in mults: # roll(wheel,ibase,p)
m += pbase*wheel[j] ; j = (j+1) % wsize
mults[m] = (j,pbase)
In particular, I have the rolled wheel streams inlined, using different variables for different "objects". It seems all over the place; is there a way to encapsulate it into a bona fide object, without loosing performance? (last time when I used functions for some encapsulation, efficiency suffered).
Answering this SO question recently, I've developed the following code (based on a well-known Active Code recipe, as discussed here):
wheel = [2,4,2,4,6,2,6,4,2,4,6,6,2,6,4,2,6,4,6,8,4,2,4,2,
4,8,6,4,6,2,4,6,2,6,6,4,2,4,6,2,6,4,2,4,2,10,2,10]
wsize = 48
def primes():
yield from (2, 3, 5, 7)
yield from wsieve()
def wsieve(): # wheel-sieve, by Will Ness. cf. ideone.com/WFv4f
yield 11 # cf. https://stackoverflow.com/a/10733621/849891
mults = {} # https://stackoverflow.com/a/19391111/849891
ps = wsieve()
p = next(ps)
psq, c, i = p*p, 11, 0 # 13 = 11 + wheel[0]
cbase, ibase = 11, 0
while True:
c += wheel[i] ; i = (i+1) % wsize # 17 = 13 + wheel[1]
if c in mults:
(j,pbase) = mults.pop(c) # add(mults, NEXT c, j, pbase)
elif c < psq:
yield c ; continue
else: # (c==psq)
while not cbase == p:
cbase += wheel[ibase]
ibase = (ibase+1) % wsize # ibase - initial offset into wheel, for p
j, pbase = ibase, p # add(mults, NEXT c, ibase, p)
p = next(ps) ; psq = p*p
m = c + pbase*wheel[j] ; j = (j+1) % wsize # mults(p) = map (*p)
while m in mults: # roll(wheel,ibase,p)
m += pbase*wheel[j] ; j = (j+1) % wsize
mults[m] = (j,pbase)
In particular, I have the rolled wheel streams inlined, using different variables for different "objects". It seems all over the place; is there a way to encapsulate it into a bona fide object, without loosing performance? (last time when I used functions for some encapsulation, efficiency suffered).