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#!/usr/bin/env ruby
# generate random DNA sequence of approx. the given totallength, such that the
# sequence are ordered according to their length, with the shortest sequences
# coming first. Stefan Kurtz, September 2012
if ARGV.length != 1
STDERR.puts "Usage: #{$0} <totallength>"
exit 1
end
srand=37739292920
def randseq(width,len)
seq = ""
currentwidth=0
0.upto(len-1) do |idx|
r = rand(3)
cc = ['a','c','g','t'][rand(4)]
seq += "#{cc}"
if currentwidth < width
currentwidth+=1
else
seq += "\n"
currentwidth=0
end
end
return seq.chomp
end
totallength = ARGV[0].to_i
currentlen = 100
currentseqnum = 0
seqnumofthislength = 1 + rand(10)
sumlen = 0
seqnum = 0
while sumlen < totallength
puts ">sequence #{seqnum} of length #{currentlen}\n#{randseq(70,currentlen)}"
seqnum+=1
sumlen += currentlen
if currentseqnum < seqnumofthislength
currentseqnum+=1
else
currentseqnum=0
seqnumofthislength = 1 + rand(10)
currentlen += 43
end
end
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