optimize segment length

[williamstark01]

This is the length distribution for "LTR" repeat type:

Would it make sense to increase the segments length to ~3000 or even ~4000 so that the repeats are contained in the segments more loosely, i.e. less of them are split and there is longer non-repeat sequences around them?

[yangtcai]

It's right, maybe we can test length range from 2k to 4k, and we can see which length will have better performance :D