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August 29, 2015 14:16
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response to http://math.stackexchange.com/questions/1159073/ about GCD function
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import numpy as np | |
import matplotlib.pyplot as plt | |
%matplotlib inline | |
# http://stackoverflow.com/questions/11175131/code-for-greatest-common-divisor-in-python | |
def gcd(x, y): | |
while y != 0: | |
(x, y) = (y, x % y) | |
return x | |
# a hack | |
def gcdsteps(x, y): | |
c = 0 | |
while y != 0: | |
(x, y) = (y, x % y) | |
c += 1 | |
return c | |
# my work | |
X = [gcdsteps(int(1000000*np.random.random()),int(1000000*np.random.random())) for s in range(100) for t in range(100)] | |
plt.hist( X, bins = np.arange(30)) | |
plt.show() |
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bits = np.random.random(len(P)) | |
P = [2,3,5,7,11,13,17,19] | |
P = np.array(P) | |
P1, P2 = P[bits > 0.5], P[bits < 0.5] | |
def smooth(P): | |
X = [1] | |
for p in P: | |
B = [p**k for k in np.arange(6*np.log(10)/np.log(p)).astype(int)] | |
X = [x*b for x in X for b in B if(x*b) < 10**6] | |
return X | |
plt.hist([gcdsteps(s,t) for s in smooth(P1) for t in smooth(P2)], bins = np.arange(30)) | |
plt.show() | |
# or print smooth relatively prime pairs | |
# | |
# (540225, 131072, 12), | |
# (385875, 524288, 13), | |
# (275625, 524288, 11), | |
# (196875, 262144, 10), | |
A = [a for a in smooth(P1)[:] if a > 100000] | |
B = [b for b in smooth(P1)[:] if b > 100000] | |
relativelyPrime = [(s,t, gcdsteps(s,t)) for s in A for t in B if gcd(s,t) == 1 ] |
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