def main():
print "testing hash functions..."
kmer1 = dna("ATCGATCGATCGATCG")
kmer2 = dna("ATCGATCGATCGATCG")
K = 16
assert hash_forward(kmer1) == hash_forward(kmer2)
h1, r1 = hash_forward(kmer1)
h2, r2 = hash_forward(kmer2)
assert kmer1 == hash_reverse(h1, K)
assert hash_reverse(r1, K) == "CGATCGATCGATCGAT"
assert hash_reverse(r1, K) == hash_reverse(r2, K)
assert hash_reverse(h1, K) == hash_reverse(h2, K)
def hash_reverse(hashval, K):
val = long(hashval) & 3L
bases = [""] * K
bases[-1] = bits_to_base(val)
hashval = long(hashval)
for i in xrange(1, K):
hashval = hashval >> 2L
val = hashval & 3L
bases[-i - 1] = bits_to_base(val)
return dna("".join(bases))
def rand_dna(L):
s = bases * (L // 4)
random.shuffle(s)
return dna(''.join(s))
