:orphan:

.. _find_prime.py:

find_prime.py
=============

.. code-block:: py
    :linenos:


    """
    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()