On Saturday 02 March 2013 11:31, Varadharajan Srinivasan wrote: > For instance, if I try the following input file : > [...] &system > ibrav= 2, celldm(1) = 10.35, nat= 2, ntyp= 1, > ecutwfc= 20.0, > ecutrho=80.0, > nr3 = 28 [...] > I get the following in the output (24 instead of the 28 that I ask for) > > Dense grid: 3383 G-vectors FFT dimensions: ( 24, 24, 24)
you have to set all three FFT dimensions, not just one. See Modules/griddim.f90, subroutine realspace_grids_init. By the way, in your case the system has three crystal axis of the same length. You shouldn't set them to different FFT dimensions. While the main code should still work, there will be at least some cases in which symmetrization will not work if the FFT grid breaks the symmetry of the crystal. P. --- Paolo Giannozzi, IOM-Democritos and DCFA, Univ. Udine
