Explaining cache with python – Russell Ballestrini

Topic: https://russell.ballestrini.net/explaining-cache-with-python/

Comments

unverified 9y, 70d ago [edited]

instead of writing this line

for i in range( 2, x ):

Can't we use the cache to build a prime list for our advantage?

for i in primes_list:

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russell 9y, 70d ago [edited]

In this case the cache is built using a python dictionary. We can check this dictionary first before computing whether a given number is prime.

for i in range(2, x):

This syntax counts from 2 to x-1 and assigns the number to i. We have to do this to test if x is ever divisible by i without a remainder. If we ever modulus x by i and get 0 (no remainder) then x is not prime.

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russell 9y, 70d ago [edited]

Update - My new laptop is significantly faster at computing primes:

>>> from time import time
>>> from primer import Primer
>>> p = Primer()
>>> s1 = time();p.is_prime( 97352613 );e1 = time()
False
>>> s2 = time();p.is_prime( 97352613 );e2 = time()
False
>>> e1 - s1
2.10681414604187
>>> e2 - s2
0.01556706428527832

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unverified 6y, 259d ago

thanks

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