Hello Vinod,
Sorry for the long delay.
I have been trying to run the simulation of GW150914 given in gallery .The simulation ran succesfully .However I am only getting a partial waveform .The merger and the ringdown phase is not being captured .I am attaching both the waveform and a gnuplot showing the completing of merger . There is also another doubt I have .In the gallery while creating the job for this simulation there is a command called --define N which is set to 28 .Could someone tell me whats the purpose of that and help me understand whats going wrong ?
I cannot tell for sure since I do not know how long you ran the simulation. My first guess would be that the waveform has not yet had time to travel to the location of the detector at r=500. Since the source is the black holes at about r=0 it will take the wave about 500 time units to travel the distance of 500 space units (speed of light is c=1 in the simulation).
A second issue to consider is that if you have multiple output-NNNN directories then you have to first concatenate the output data file to have access to all data. Specialized analysis tools like kuibit, SimulationTools and PostCactus (see https://docs.einsteintoolkit.org/et-docs/Analysis_and_post-processing) will usually do this automatically but if you use your own Python or gnuplot code then you will have to do so yourself.
Yours, Roland