cms.ft.bit_reverse_compare のソースコード

import sys
import time


val10 = 0b1100011011000110110001101100011110001101100011011000110110001101
niter = 100000




def bit_reverse(val):
    ret = 0
    while 1:
        v0 = val & 0b001
        ret = ret | v0
        val = val >> 1
        if val == 0:
            break
        else:
            ret = ret << 1
    return ret





def bit_reverse_nobitop(val):
    ret = 0
    while 1:
        v0 = val % 2
        ret = ret + v0
        val = val // 2
        if val == 0:
            break
        else:
            ret = ret * 2
    return ret





def bit_reverse_nobitop2(val):
    ret = 0
    while 1:
        v0 = val % 2
        ret += v0
        val //= 2
        if val == 0:
            break
        else:
            ret *= 2
    return ret





def main():
    global val10, niter

    if len(sys.argv) > 1:
        val10 = int(sys.argv[1], 2)
    if len(sys.argv) > 2:
        niter = int(sys.argv[2])

    print("")
    print("Base 10 input: ", val10)
    print("Base 2: {:b}".format(val10))

    print("")
    print("by bitwise operation")
    vrev = bit_reverse(val10)
    print("reversed in Base 10 =", vrev)
    print("         in Base 2  = {:b}".format(vrev))

    print("without bitwise operation")
    vrev = bit_reverse_nobitop(val10)
    print("reversed in Base 10 =", vrev)
    print("         in Base 2  = {:b}".format(vrev))

    print("")
    print("Time for {} iterations".format(niter))

    st = time.time()
    for _ in range(niter):
        bit_reverse(val10)
    et = time.time()
    print("by bitwise operation     : {} s".format(et - st))

    st = time.time()
    [bit_reverse(val10) for _ in range(niter)]
    et = time.time()
    print("by bitwise operation (list incl): {} s".format(et - st))

    st = time.time()
    for _ in range(niter):
        bit_reverse_nobitop(val10)
    et = time.time()
    print("without bitwise operation: {} s".format(et - st))

    st = time.time()
    for _ in range(niter):
        bit_reverse_nobitop2(val10)
    et = time.time()
    print("without bitwise operation #2: {} s".format(et - st))

    print("")



if __name__ == "__main__":
    main()