def find_max_in_range(fname, frange):
    f = open(fname)
    n_max = 0

    f.seek(frange[0])

    while f.tell() < frange[1]:
        n = f.readline()

        if int(n) > n_max:
            n_max = int(n)

    f.close()

    return n_max

---

def find_file_ranges(fname, chunks):
    f = open(fname)

    f.seek(0,2)
    fsize = f.tell()

    ranges = []
    chunk_size = fsize // chunks
    start = 0
    for i in range(chunks):
        f.seek(start + chunk_size)
        l = f.readline()
        end = min(start + chunk_size + len(l) - 1, fsize)
        ranges.append( (start, end) )
        start = end + 1

    f.close()
    return ranges

---

from multiprocessing import Pool

def find_max_in_range_wrapper(args):
    max_in_range = find_max_in_range(args[0],
                                     args[1])
    print("Chunk %i-%i done. Max: %i" %
        (args[1][0], args[1][1], max_in_range))
    return max_in_range 

---

franges = find_file_ranges(fname, nchunks)

print("Dividing the file into %i chunks:" % nchunks)

for frange in franges:
    print("  %i - %i" % (frange[0],frange[1]))
print("\n")

p = Pool(nchunks)
args = zip([fname]*nchunks, franges)
res = p.map(find_max_in_range_wrapper, args)

print("\n")
print("Maximum: %i" % (max(res)))

---

>>> l = [1, 2, 3, 4]
>>> map(lambda x: x*x, l)
[1, 4, 9, 16]
>>> filter(lambda x: x % 2 == 0, l)
[2, 4]
>>> reduce(lambda x, y: x + y, l, 0)
10
>>> 

---

franges = find_file_ranges(fname, nchunks)

print("Dividing the file into %i chunks:" % nchunks)

for frange in franges:
    print("  %i - %i" % (frange[0],frange[1]))
print("\n")

p = Pool(nchunks)
args = zip([fname]*nchunks, franges)
res = p.map(find_max_in_range_wrapper, args)

print("\n")
print("Maximum: %i" % (reduce(max, res)))