How to extract the raw data of phonon dispersion curves, the generated curve is being denoted by stars which do not give an idea how it is connected?
Kindly please provide inputs on the same .
If you’d got as far as looking at example 5 you would have seen the answer to this. If all else fails, read the document that comes with the code. 
Sure,
In the output phonon dispersion curve of example 5, the following negative frequencies are observed,
1 -0.000018
1 -0.000017
1 -0.000014
Is it fine to have above negative values while defining the dynamic stability of the system. Because literature say that no negative frequencies must be there. Kindly clarify
Computers don’t work to infinite precision and so you need to use your judgement to assess whether something is numerically close to zero or a physically significant imaginary mode.