[Pw_forum] Single q-point calculation

[Bipul Rakshit]

I am doing phonon calculation of graphene.

on running ph.x, with 6x6x1 q-grid it gives me a set of points

    * Dynamical matrices for ( 6, 6, 1,)  uniform grid of q-points
     (   7q-points):
       N         xq(1)         xq(2)         xq(3)
       1   0.000000000   0.000000000   0.000000000
       2   0.000000000   0.192450090   0.000000000
       3   0.000000000   0.384900179   0.000000000
       4   0.000000000  -0.577350269   0.000000000
       5   0.166666667   0.288675135   0.000000000
       6   0.166666667   0.481125224   0.000000000
       7   0.333333333   0.577350269   0.000000000
*
in my output file.
I just want to ask, that is it wise to run the calculation using ldisp =true(
graph.ph.in), which calculate the phonon frequencies one by one or

Seven different calculations, using the above seven different q-points,
using single q-point calculation (graph-singleq.ph.in)

Is both the ways gives final result same?

Because the latter method takes less time, than previous.


thanks




--
Bipul Rakshit
Research Fellow,
S N Bose Centre for Basic Sciences,
Salt Lake,
Kolkata 700 098
India
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