source code
# The Computer Language Benchmarks Game
# http://benchmarksgame.alioth.debian.org/
# Contributed by Sokolov Yura
$last = 42.0
def gen_random (max,im=139968,ia=3877,ic=29573)
(max * ($last = ($last * ia + ic) % im)) / im
end
alu =
"GGCCGGGCGCGGTGGCTCACGCCTGTAATCCCAGCACTTTGG"+
"GAGGCCGAGGCGGGCGGATCACCTGAGGTCAGGAGTTCGAGA"+
"CCAGCCTGGCCAACATGGTGAAACCCCGTCTCTACTAAAAAT"+
"ACAAAAATTAGCCGGGCGTGGTGGCGCGCGCCTGTAATCCCA"+
"GCTACTCGGGAGGCTGAGGCAGGAGAATCGCTTGAACCCGGG"+
"AGGCGGAGGTTGCAGTGAGCCGAGATCGCGCCACTGCACTCC"+
"AGCCTGGGCGACAGAGCGAGACTCCGTCTCAAAAA"
iub = [
["a", 0.27],
["c", 0.12],
["g", 0.12],
["t", 0.27],
["B", 0.02],
["D", 0.02],
["H", 0.02],
["K", 0.02],
["M", 0.02],
["N", 0.02],
["R", 0.02],
["S", 0.02],
["V", 0.02],
["W", 0.02],
["Y", 0.02],
]
homosapiens = [
["a", 0.3029549426680],
["c", 0.1979883004921],
["g", 0.1975473066391],
["t", 0.3015094502008],
]
def make_repeat_fasta(id, desc, src, n)
puts ">#{id} #{desc}"
v = nil
width = 60
l = src.length
s = src * ((n / l) + 1)
s.slice!(n, l)
puts (s.scan(/.{1,#{width}}/).join("\n"))
end
def make_random_fasta(id, desc, table, n)
puts ">#{id} #{desc}"
rand, v = nil,nil
width = 60
chunk = 1 * width
prob = 0.0
table.each{|v| v[1]= (prob += v[1])}
for i in 1..(n/width)
puts (1..width).collect{
rand = gen_random(1.0)
table.find{|v| v[1]>rand}[0]
}.join
end
if n%width != 0
puts (1..(n%width)).collect{
rand = gen_random(1.0)
table.find{|v| v[1]>rand}[0]
}.join
end
end
n = (ARGV[0] or 27).to_i
make_repeat_fasta('ONE', 'Homo sapiens alu', alu, n*2)
make_random_fasta('TWO', 'IUB ambiguity codes', iub, n*3)
make_random_fasta('THREE', 'Homo sapiens frequency', homosapiens, n*5)