update from O'Reilly repo

20-concurrency/primes/py36/primes.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+
+import math
+
+PRIME_FIXTURE = [
+    (2, True),
+    (142702110479723, True),
+    (299593572317531, True),
+    (3333333333333301, True),
+    (3333333333333333, False),
+    (3333335652092209, False),
+    (4444444444444423, True),
+    (4444444444444444, False),
+    (4444444488888889, False),
+    (5555553133149889, False),
+    (5555555555555503, True),
+    (5555555555555555, False),
+    (6666666666666666, False),
+    (6666666666666719, True),
+    (6666667141414921, False),
+    (7777777536340681, False),
+    (7777777777777753, True),
+    (7777777777777777, False),
+    (9999999999999917, True),
+    (9999999999999999, False),
+]
+
+NUMBERS = [n for n, _ in PRIME_FIXTURE]
+
+# tag::IS_PRIME[]
+def is_prime(n: int) -> bool:
+    if n < 2:
+        return False
+    if n == 2:
+        return True
+    if n % 2 == 0:
+        return False
+
+    root = math.floor(math.sqrt(n))
+    for i in range(3, root + 1, 2):
+        if n % i == 0:
+            return False
+    return True
+# end::IS_PRIME[]
+
+if __name__ == '__main__':
+
+    for n, prime in PRIME_FIXTURE:
+        prime_res = is_prime(n)
+        assert prime_res == prime
+        print(n, prime)

20-concurrency/primes/py36/procs.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+
+"""
+procs.py: shows that multiprocessing on a multicore machine
+can be faster than sequential code for CPU-intensive work.
+"""
+
+# tag::PRIMES_PROC_TOP[]
+import sys
+from time import perf_counter
+from typing import NamedTuple
+from multiprocessing import Process, SimpleQueue, cpu_count  # <1>
+from multiprocessing import queues  # <2>
+
+from primes import is_prime, NUMBERS
+
+class PrimeResult(NamedTuple):  # <3>
+    n: int
+    prime: bool
+    elapsed: float
+
+JobQueue = queues.SimpleQueue  # <4>
+ResultQueue = queues.SimpleQueue  # <5>
+
+def check(n: int) -> PrimeResult:  # <6>
+    t0 = perf_counter()
+    res = is_prime(n)
+    return PrimeResult(n, res, perf_counter() - t0)
+
+def worker(jobs: JobQueue, results: ResultQueue) -> None:  # <7>
+    while True:
+        n = jobs.get()  # <8>
+        if n == 0:
+            break
+        results.put(check(n))  # <9>
+# end::PRIMES_PROC_TOP[]
+
+# tag::PRIMES_PROC_MAIN[]
+def main() -> None:
+    if len(sys.argv) < 2:  # <1>
+        workers = cpu_count()
+    else:
+        workers = int(sys.argv[1])
+
+    print(f'Checking {len(NUMBERS)} numbers with {workers} processes:')
+
+    jobs: JobQueue = SimpleQueue() # <2>
+    results: ResultQueue = SimpleQueue()
+    t0 = perf_counter()
+
+    for n in NUMBERS:  # <3>
+        jobs.put(n)
+
+    for _ in range(workers):
+        proc = Process(target=worker, args=(jobs, results))  # <4>
+        proc.start()  # <5>
+        jobs.put(0)  # <6>
+
+    while True:
+        n, prime, elapsed = results.get()  # <7>
+        label = 'P' if prime else ' '
+        print(f'{n:16}  {label} {elapsed:9.6f}s')  # <8>
+        if jobs.empty():  # <9>
+            break
+
+    elapsed = perf_counter() - t0
+    print(f'Total time: {elapsed:.2f}s')
+
+if __name__ == '__main__':
+    main()
+# end::PRIMES_PROC_MAIN[]