find_prime.py

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"""
This example demonstrates how Python code can be run in a browser, which
is for many things faster than CPython. We run the exact same code to find
the n-th prime on both Python and JS and measure the performance.
"""

from time import perf_counter

from flexx import app


def find_prime(n):
    primes = []

    def isprime(x):
        if x <= 1:
            return False
        elif x == 2:
            return True
        for i in range(2, x//2+1):
            if x % i == 0:
                return False
        return True

    t0 = perf_counter()
    i = 0
    while len(primes) < n:
        i += 1
        if isprime(i):
            primes.append(i)
    t1 = perf_counter()
    print(i, 'found in ', t1-t0, 'seconds')


class PrimeFinder(app.Model):

    def find_prime_py(self, n):
        find_prime(n)

    def find_prime_js(self, n):
        self.call_js('_find_prime(%i)' % n)

    class JS:

        def _find_prime(self, n):
            find_prime(n)


if __name__ == '__main__':

    # Create app instance
    finder = app.launch(PrimeFinder, 'app or chrome-app')

    finder.find_prime_py(2000)  # 0.7 s
    finder.find_prime_js(2000)  # 0.2 s

    app.run()