According to http://www.ebi.ac.uk/~zerbino/velvet/, velvet can be multithreaded. But how to do it? When I do

```
./velveth

Usage:
./velveth directory hash_length {[-file_format][-read_type][-separate|-interleaved] filename1 [filename2 ...]} {...} [options]
```

My question is how to run velveth multithreaded? Where is the multi-thread flag (usually `-t` or `-p`)? I'm running 1.2.10.
<p>For threading to work, Velvet has to be installed with <code>make &#39;OPENMP=1&#39;</code>. Then you can control threading via <code>export OMP_NUM_THREADS=7</code>. See <a href="https://helix.nih.gov/Applications/velvet_manual.pdf">Velvet Manual</a> Section 2.3.6.</p>
