getting used/available memory

[Peter Schneider-Kamp]

Hei!

I seem to have some nice memory leaks in my modular
arithmetic module. To find out where the memory goes
I'd like to find out how much memory is occupied/free
at a given time. I did not find anything in sys or os
on first sight. Where do I have to go?

I am using python 1.5.2 on linux. The routine in
question is:

def tolong(u,m):
  R = len(u)
  v = copy.copy(u)
  n = map(long,m)
  c = []
  for j in range(R):
    if (j % 100)==0:
      print "o"
    c.append([])
    for k in range(R):
      c[j].append(mulinv(m[j],m[k]))
  for j in range(R-1):
    for k in range(j+1,R):
      v[k] = (v[k]-v[j])*c[j][k] % m[k]
  w = v[0]
  for j in range(R-1):
    w = w + v[j+1] * n[0]
    n[0] = n.pop(0) * n[0]
  return w

where m is a list of 10000 relative prime integers
below 2**31 and u is a list of 10000 integers which
are as well below 2**31. the system has 224 MB of
ram (96 + 128 swap) and after about 1000 iterations
the system runs out of memory and I have to
emergency sync and reboot.
Would using JPython fix this problem?

thanks for any advice
Peter

P.S.: The function mulinv calculates the multiplicative
      inverse of a relative to b using the forward
      version of the extended euclidean algorithm.
      as it is used in the inner loop the memory leak
      might as well be there:

def mulinv(a,b):
  s = [1,0]
  m = b
  while b > 0:
    q, r = divmod(a,b)
    s.append(s.pop(0)-q*s[0]);
    a = b
    b = r
  return s[0] % m
--
Peter Schneider-Kamp          ++47-7388-7331
Herman Krags veg 51-11        mailto:peter at schneider-kamp.de
N-7050 Trondheim              http://schneider-kamp.de