From: Zooko O'Whielacronx zooko@zooko.com <zooko@zooko.com>
Date: Sat, 14 Apr 2007 17:54:43 +0000 (+0530)
Subject: pyfec: import a copy of mathutil.py from the pyutil library
X-Git-Url: https://git.rkrishnan.org/vdrive/%22file:/frontends/%22doc.html/%22news.html/...?a=commitdiff_plain;h=28e60f04edf87dbe66f78042cbc41e237488f2c5;p=tahoe-lafs%2Fzfec.git

pyfec: import a copy of mathutil.py from the pyutil library

darcs-hash:cee8657901117d8dd821c69a274715655ee062fd
---

diff --git a/pyfec/fec/util/mathutil.py b/pyfec/fec/util/mathutil.py
new file mode 100644
index 0000000..de95a6a
--- /dev/null
+++ b/pyfec/fec/util/mathutil.py
@@ -0,0 +1,92 @@
+# Copyright (c) 2005-2007 Bryce "Zooko" Wilcox-O'Hearn
+# mailto:zooko@zooko.com
+# http://zooko.com/repos/pyutil
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this work to deal in this work without restriction (including the rights
+# to use, modify, distribute, sublicense, and/or sell copies).
+
+"""
+A few commonly needed functions.
+"""
+
+import math
+
+def div_ceil(n, d):
+    """
+    The smallest integer k such that k*d >= n.
+    """
+    return (n/d) + (n%d != 0)
+
+def next_multiple(n, k):
+    """
+    The smallest multiple of k which is >= n.
+    """
+    return div_ceil(n, k) * k
+
+def pad_size(n, k):
+    """
+    The smallest number that has to be added to n so that n is a multiple of k.
+    """
+    if n%k:
+        return k - n%k
+    else:
+        return 0
+
+def is_power_of_k(n, k):
+    return k**int(math.log(n, k) + 0.5) == n
+
+def next_power_of_k(n, k):
+    p = 1
+    while p < n:
+        p *= k
+    return p
+
+def ave(l):
+    return sum(l) / len(l)
+
+def log_ceil(n, b):
+    """
+    The smallest integer k such that b^k >= n.
+
+    log_ceil(n, 2) is the number of bits needed to store any of n values, e.g.
+    the number of bits needed to store any of 128 possible values is 7.
+    """
+    p = 1
+    k = 0
+    while p < n:
+        p *= b
+        k += 1
+    return k
+
+def linear_fit_slope(ps):
+    """
+    @param ps a sequence of tuples of (x, y)
+    """
+    avex = ave([x for (x, y) in ps])
+    avey = ave([y for (x, y) in ps])
+    sxy = sum([ (x - avex) * (y - avey) for (x, y) in ps ])
+    sxx = sum([ (x - avex) ** 2 for (x, y) in ps ])
+    if sxx == 0:
+        return None
+    return sxy / sxx
+
+def permute(l):
+    """
+    Return all possible permutations of l.
+
+    @type l: sequence
+    @rtype a set of sequences
+    """
+    if len(l) == 1:
+        return [l,]
+
+    res = []
+    for i in range(len(l)):
+        l2 = list(l[:])
+        x = l2.pop(i)
+        for l3 in permute(l2):
+            l3.append(x)
+            res.append(l3)
+
+    return res
+
diff --git a/pyfec/setup.py b/pyfec/setup.py
index 24ba55c..3081ef6 100755
--- a/pyfec/setup.py
+++ b/pyfec/setup.py
@@ -63,7 +63,7 @@ setup(name='pyfec',
       url='http://zooko.com/repos/pyfec',
       license='GNU GPL',
       platform='Any',
-      packages=['fec', 'fec.test'],
+      packages=['fec', 'fec.util', 'fec.test'],
       classifiers=trove_classifiers,
       ext_modules=[Extension('_fec', ['fec/fec.c', 'fec/_fecmodule.c',], extra_link_args=extra_link_args, extra_compile_args=extra_compile_args, undef_macros=undef_macros),],
       )