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1#
2# Copyright (C) 2001-2012 Python Software Foundation. All Rights Reserved.
3# Modified and extended by Stefan Krah.
4#
5
6# Usage: ../../../python bench.py
7
8
9import time
10from test.support.import_helper import import_fresh_module
11
12C = import_fresh_module('decimal', fresh=['_decimal'])
13P = import_fresh_module('decimal', blocked=['_decimal'])
14
15#
16# NOTE: This is the pi function from the decimal documentation, modified
17# for benchmarking purposes. Since floats do not have a context, the higher
18# intermediate precision from the original is NOT used, so the modified
19# algorithm only gives an approximation to the correctly rounded result.
20# For serious use, refer to the documentation or the appropriate literature.
21#
22def pi_float():
23    """native float"""
24    lasts, t, s, n, na, d, da = 0, 3.0, 3, 1, 0, 0, 24
25    while s != lasts:
26        lasts = s
27        n, na = n+na, na+8
28        d, da = d+da, da+32
29        t = (t * n) / d
30        s += t
31    return s
32
33def pi_cdecimal():
34    """cdecimal"""
35    D = C.Decimal
36    lasts, t, s, n, na, d, da = D(0), D(3), D(3), D(1), D(0), D(0), D(24)
37    while s != lasts:
38        lasts = s
39        n, na = n+na, na+8
40        d, da = d+da, da+32
41        t = (t * n) / d
42        s += t
43    return s
44
45def pi_decimal():
46    """decimal"""
47    D = P.Decimal
48    lasts, t, s, n, na, d, da = D(0), D(3), D(3), D(1), D(0), D(0), D(24)
49    while s != lasts:
50        lasts = s
51        n, na = n+na, na+8
52        d, da = d+da, da+32
53        t = (t * n) / d
54        s += t
55    return s
56
57def factorial(n, m):
58    if (n > m):
59        return factorial(m, n)
60    elif m == 0:
61        return 1
62    elif n == m:
63        return n
64    else:
65        return factorial(n, (n+m)//2) * factorial((n+m)//2 + 1, m)
66
67
68print("\n# ======================================================================")
69print("#                   Calculating pi, 10000 iterations")
70print("# ======================================================================\n")
71
72to_benchmark = [pi_float, pi_decimal]
73if C is not None:
74    to_benchmark.insert(1, pi_cdecimal)
75
76for prec in [9, 19]:
77    print("\nPrecision: %d decimal digits\n" % prec)
78    for func in to_benchmark:
79        start = time.time()
80        if C is not None:
81            C.getcontext().prec = prec
82        P.getcontext().prec = prec
83        for i in range(10000):
84            x = func()
85        print("%s:" % func.__name__.replace("pi_", ""))
86        print("result: %s" % str(x))
87        print("time: %fs\n" % (time.time()-start))
88
89
90print("\n# ======================================================================")
91print("#                               Factorial")
92print("# ======================================================================\n")
93
94if C is not None:
95    c = C.getcontext()
96    c.prec = C.MAX_PREC
97    c.Emax = C.MAX_EMAX
98    c.Emin = C.MIN_EMIN
99
100for n in [100000, 1000000]:
101
102    print("n = %d\n" % n)
103
104    if C is not None:
105        # C version of decimal
106        start_calc = time.time()
107        x = factorial(C.Decimal(n), 0)
108        end_calc = time.time()
109        start_conv = time.time()
110        sx = str(x)
111        end_conv = time.time()
112        print("cdecimal:")
113        print("calculation time: %fs" % (end_calc-start_calc))
114        print("conversion time: %fs\n" % (end_conv-start_conv))
115
116    # Python integers
117    start_calc = time.time()
118    y = factorial(n, 0)
119    end_calc = time.time()
120    start_conv = time.time()
121    sy = str(y)
122    end_conv =  time.time()
123
124    print("int:")
125    print("calculation time: %fs" % (end_calc-start_calc))
126    print("conversion time: %fs\n\n" % (end_conv-start_conv))
127
128    if C is not None:
129        assert(sx == sy)
130