Not sure what the problem with the "cube" file is. FFT arrays obey periodic boundary conditions: the index runs from 1 to nr, and f(nr+1) => f(1) . Is this the problem?
About the denser grid: I don't think it is that simple. Either you perform a Fourier interpolation (have a look at code "voronoy.f90" in v.4.1.3) or you perform a local interpolation in real space. P. On Mon, 2013-02-18 at 16:56 +0100, Thomas Gruber wrote: > Hallo all, > > I have two problems: > 1. I like to have the charge_density.xsf/*.cube with output_format=5/6, > but with a denser grid than the FFT grid. nx,ny,nz are ignored in this > case. They work for output_format=3 with an orthorhombic box, but I want > my unit cell. > > 2. The output format for *.xsf works fine, but not for *.cube. For xsf > the data_grid is x+1,y+1,z+1, but not for cube (x,y,z). The *.cube also > needs x+1,y+1,z+1 to get the write volume, atom positions and no offset > along the unit cell surface for the charge density. I tried to correct > the cube.f90 in PP but the charge density data is still not correct. I > increased nr# by 1 in each case: > > WRITE(ounit,*) 'Cubfile created from PWScf calculation' > WRITE(ounit,*) ' Total SCF Density' > ! origin is forced to (0.0,0.0,0.0) > WRITE(ounit,'(I5,3F12.6)') nat, 0.0d0, 0.0d0, 0.0d0 > WRITE(ounit,'(I5,3F12.6)') nr1+1, (alat*at(i,1)/dble(nr1),i=1,3) > WRITE(ounit,'(I5,3F12.6)') nr2+1, (alat*at(i,2)/dble(nr2),i=1,3) > WRITE(ounit,'(I5,3F12.6)') nr3+1, (alat*at(i,3)/dble(nr3),i=1,3) > > DO i=1,nat > nt = ityp(i) > ! find atomic number for this atom. > at_num = atomic_number(trim(atm(nt))) > at_chrg= dble(at_num) > ! at_chrg could be alternatively set to valence charge > ! positions are in cartesian coordinates and a.u. > ! > ! wrap coordinates back into cell. > tpos = matmul( transpose(bg), tau(:,i) ) > tpos = tpos - nint(tpos - 0.5d0) > inpos = alat * matmul( at, tpos ) > WRITE(ounit,'(I5,5F12.6)') at_num, at_chrg, inpos > ENDDO > > DO i1=1,nr1+1 > DO i2=1,nr2+1 > WRITE(ounit,'(6E13.5)') (rho(i1,i2,i3),i3=1,nr3+1) > ENDDO > ENDDO > > Can someone give me the correction for cube.f90 and a way to increase > the data_grid density for the output_format=5/6? > > Sincerely, > > Thomas Gruber > -- Paolo Giannozzi, IOM-Democritos and University of Udine, Italy