def lab2ind(im, colors=256):
"""convert a Lab image to indexed colors
:param a: nparray (x,y,n) containing image
:param colors: int number of colors or predefined Palette
:ref: http://scikit-learn.org/stable/auto_examples/cluster/plot_color_quantization.html
"""
#http://stackoverflow.com/questions/10818546/finding-index-of-nearest-point-in-numpy-arrays-of-x-and-y-coordinates
if isinstance(colors, int):
p = palette(im, colors) #
pal = [Color(c, 'lab') for c in p]
else:
pal = colors
p = [c.lab for c in itertools2.flatten(pal)]
w, h, d = im.shape
s = w * h #number of pixels
flat = np.reshape(im, (s, d))
from scipy.spatial import cKDTree as KDTree #compiled is MUCH faster
mytree = KDTree(p)
_, indexes = mytree.query(flat)
im = indexes.reshape(w, h)
return im, pal
def lab2ind(im,colors=256):
"""convert a Lab image to indexed colors
:param a: nparray (x,y,n) containing image
:param colors: int number of colors or predefined Palette
:ref: http://scikit-learn.org/stable/auto_examples/cluster/plot_color_quantization.html
"""
#http://stackoverflow.com/questions/10818546/finding-index-of-nearest-point-in-numpy-arrays-of-x-and-y-coordinates
if isinstance(colors,int):
p=palette(im,colors) #
pal=[Color(c,'lab') for c in p]
else:
pal=colors
p=[c.lab for c in itertools2.flatten(pal)]
w, h, d = im.shape
s=w*h #number of pixels
flat = np.reshape(im, (s, d))
from scipy.spatial import cKDTree as KDTree #compiled is MUCH faster
mytree = KDTree(p)
_, indexes = mytree.query(flat)
im=indexes.reshape(w,h)
return im,pal
1,
lambda n:len(math2.sieve(n+1,oneisprime=True)),
lambda n:True, #all integers are in this sequence.
desc="pi(n), the number of primes <= n. Sometimes called PrimePi(n)"
)
"""
A018239=A006862.filter(
math2.is_prime,
desc='Primorial primes: form product of first k primes and add 1, then reject unless prime.'
)
A007504=A000040.accumulate()
A001223=A000040.pairwise(operator.sub)
A077800=Sequence(itertools2.flatten(math2.twin_primes()))
A001097=A077800.unique()
A001359=Sequence(itertools2.itemgetter(math2.twin_primes(),0),desc="Lesser of twin primes.")
A006512=Sequence(itertools2.itemgetter(math2.twin_primes(),1),desc="Greater of twin primes.")
A037074=Sequence(map(math2.mul,math2.twin_primes()), desc="Numbers that are the product of a pair of twin primes")
def count_10_exp(iterable):
"""generates number of iterable up to 10^n."""
l=10
c=0
for n in iterable:
if n>l:
def _hash_result(result):
return math2.num_from_digits(itertools2.flatten(result), 2)
A000720=Sequence(
1,
lambda n:len(math2.sieve(n+1,oneisprime=True)),
lambda n:True, #all integers are in this sequence.
desc="pi(n), the number of primes <= n. Sometimes called PrimePi(n)"
)
"""
A018239=A006862.filter(
math2.is_prime,
desc='Primorial primes: form product of first k primes and add 1, then reject unless prime.'
)
A001223=A000040.pairwise(operator.sub)
A077800=Sequence(itertools2.flatten(math2.twin_primes()))
A001097=Sequence(itertools2.unique_sorted(A077800))
A001359=Sequence(itertools2.itemgetter(math2.twin_primes(),0),desc="Lesser of twin primes.")
A006512=Sequence(itertools2.itemgetter(math2.twin_primes(),1),desc="Greater of twin primes.")
A037074=Sequence(six.moves.map(math2.mul,math2.twin_primes()), desc="Numbers that are the product of a pair of twin primes")
def count_10_exp(iterable):
"""generates number of iterable up to 10^n."""
l=10
c=0
for n in iterable:
if n>l:
