install ns3.21 in ubuntu16.04 error
<ol>
<li><p>When I try to "sudo apt-get install gsl-bin libgsl0-dev libgsl0ldbl" 16.04 cannot find the package libgsl0ldbl for the reason that libgsl0-dev is replaced by libgsl-dev and libgsl0ldbl is obslolete, now replaced by libgsl2. I don't know if it matters.</p></li>
<li><p>When I run the command "./build.py âenable-examples âenable-tests".
It failed with the message :</p>

<h1>Build NS-3</h1></li>
</ol>

<p>Entering directory <code>./ns-3.25'
Traceback (most recent call last):
</code>File "./build.py", line 171, in 
    sys.exit(main(sys.argv))
  File "./build.py", line 162, in main
    build_ns3(config, build_examples, build_tests, args, build_options)
  File "./build.py", line 81, in build_ns3
    run_command(cmd) # waf configure ...
  File "/home/limeng/ns3/ns-allinone-3.25/util.py", line 20, in run_command
    print(" => ", ' '.join(argv))` 
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 0: ordinal not in range(128)</p>

<p>I personally tried to do that and it didn't worth the trouble at all so I ended up installing it on Ubuntu 14.04.</p>

<p>In case you have no other choice, try watching this <a href="https://www.youtube.com/watch?v=SckgZkBg-Oc" rel="nofollow">tutorial</a></p>

python ubuntu ubuntu-16.04 ns-3