On Thu, 23 Nov 2006, wang yanchao wrote: WY> Dear users: WY> when I used run_pp to caculate the densety of charge,I found a qustion WY> that the number of points are 55 55 55 in output file.but in fact what I WY> input the nx,ny,nz is100,100,100.then I read the code of PP,I found that 55 WY> 55 55 is nr1+1 nr2+1 nr3+1.I think "nr" is the K_point.In fact I
nr1,nr2,nr3 (and its siblings nr1s,nr2s,nr3s and nr1b,nr2b,nr3b) are traditionally the grid dimensions of the real space meshes on which the density is stored (e.g. for evaluating the functionals or computing forces). see, e.g., Modules/input_parameters.f90 this is independent of your k-point selection. WY> ,however,caculated the K_point is gamma.This make me confused.In an addtion WY> ,I found the value of nx,ny nz is limited in code of PP.the max value is WY> 64.I do not know the reson why it choose this value.If you know ,please tell WY> me .Thank you in advance. unless you need a specific real space resolution, you should stick with the grid dimensions used in your pw.x calculations. for tighter (or coarser) grids the code interpolates via fourier transforms (as the real space density is usually generated from the g-space representation when needed). hope that helps, axel. WY> -- ======================================================================= Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu http://www.cmm.upenn.edu Center for Molecular Modeling -- University of Pennsylvania Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323 tel: 1-215-898-1582, fax: 1-215-573-6233, office-tel: 1-215-898-5425 ======================================================================= If you make something idiot-proof, the universe creates a better idiot.
