<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello,<div><br><div><div>Il giorno 28/lug/2011, alle ore 23.03, chengyu yang ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">Dear All,<br>         I am trying to calculate the complex bands and the transmission of a (5,5) defectless carbon nanotube using PWCOND.x, however, the calculation process is very slow and I can see it kind of stopped at the point:  ngper, shell number =         2809         299.<br></blockquote><div><br></div><div>Your value of ngper is quite large for this kind of calculations, you can't afford it without using a lot of processors in a parallel calculation. Moreover,  as far as I know the calculation of the complex bands is not completely parallelized at the moment, hence if your leads have a very large cross section and contain really a lot of atoms, I'm afraid that the calculation is hardly feasible with the current implementation.</div><div><br></div><div>In your case, the calculation should be feasible with 8-16 processors in parallel (if nodes have enough memory), but only if you use USPP, so that you will be able to reduce the ecutwfc down to 30-35 Ry.</div><div><br></div><div>In the PWcond input file I would reduce epsproj to 10^-5 or 10^-6, depending on the level of accuracy required (but you should do a small test on this).</div><div><br></div><div><br></div><div>HTH</div><div><br></div><div>GS</div><div><br></div><br><blockquote type="cite">
         My input files are like this:<br><br>  ##################################################################################<br>scf input file:<br><br>&CONTROL<br>                 calculation = 'scf' ,<br>
                restart_mode = 'from_scratch' ,<br>                       prefix = '55' ,<br> /<br> &SYSTEM<br>                       ibrav = 6,<br>                   celldm(1) = 21.764541128,celldm(3)=0.213765379<br>
                         nat = 20,<br>                        ntyp = 1,<br>                     ecutwfc = 75 ,<br> /<br> &ELECTRONS<br>                    conv_thr = 1.0d-8 ,<br>                 mixing_beta = 0.7 ,<br>
 /<br>ATOMIC_SPECIES<br>    C   12.01100  C.pz-vbc.UPF <br><br>ATOMIC_POSITIONS angstrom<br><br>  C        3.409595     0.000000    -1.231179<br>  C        3.113484     1.389805    -1.231179<br>  C        2.758420     2.004110    -0.000000<br>
  C        1.701954     2.954436    -0.000000<br>  C        1.053623     3.242718    -1.231179<br>  C       -0.359664     3.390572    -1.231179<br>  C       -1.053623     3.242718    -0.000000<br>  C       -2.283903     2.531625    -0.000000<br>
  C       -2.758420     2.004110    -1.231179<br>  C       -3.335768     0.705684    -1.231179<br>  C       -3.409595     0.000000    -0.000000<br>  C       -3.113484    -1.389805    -0.000000<br>  C       -2.758420    -2.004110    -1.231179<br>
  C       -1.701954    -2.954436    -1.231179<br>  C       -1.053623    -3.242718     0.000000<br>  C        0.359664    -3.390572     0.000000<br>  C        1.053623    -3.242718    -1.231179<br>  C        2.283903    -2.531625    -1.231179<br>
  C        2.758420    -2.004110     0.000000<br>  C        3.335768    -0.705684     0.000000<br><br><br>  <br><br>K_POINTS automatic <br> 1 1 5 0 0 0<br><br><br>###############################################################################<br>
<br><a href="http://pwcond.in/">pwcond.in</a> file:<br><br><br>&inputcond<br>    prefixl='55'<br>    band_file ='bands.cnt55'<br>    ikind=0<br>    energy0=4.d0<br>    denergy=-0.1d0<br>    ewind=3.d0<br>
    epsproj=1.d-4<br>    delgep = 1.d-9<br>    cutplot = 3.d0<br> /<br>    1<br>    0.0 0.0 1.0<br>    5<br><br>###########################################################<br>and the output file:<br><br>     GEOMETRY:<br>
<br>     lattice parameter (a_0)   =      21.7645  a.u.<br>     the volume                =    2203.8697 (a.u.)^3<br>     the cross section         =     473.6953 (a.u.)^2<br>     l of the unit cell        =       0.2138 (a_0)<br>
     number of atoms/cell      =           20<br>     number of atomic types    =            1<br><br>     crystal axes: (cart. coord. in units of a_0)<br>               a(1) = (  1.0000  0.0000  0.0000 )  <br>               a(2) = (  0.0000  1.0000  0.0000 )  <br>
               a(3) = (  0.0000  0.0000  0.2138 )  <br><br><br>   Cartesian axes<br><br>     site n.     atom                  positions (a_0 units)<br>          1           C   tau(  1)=(  0.2960  0.0000  0.1069  )<br>          2           C   tau(  2)=(  0.2703  0.1207  0.1069  )<br>
          3           C   tau(  3)=(  0.2395  0.1740  0.2138  )<br>          4           C   tau(  4)=(  0.1478  0.2565  0.2138  )<br>          5           C   tau(  5)=(  0.0915  0.2816  0.1069  )<br>          6           C   tau(  6)=( -0.0312  0.2944  0.1069  )<br>
          7           C   tau(  7)=( -0.0915  0.2816  0.2138  )<br>          8           C   tau(  8)=( -0.1983  0.2198  0.2138  )<br>          9           C   tau(  9)=( -0.2395  0.1740  0.1069  )<br>         10           C   tau( 10)=( -0.2896  0.0613  0.1069  )<br>
         11           C   tau( 11)=( -0.2960  0.0000  0.2138  )<br>         12           C   tau( 12)=( -0.2703 -0.1207  0.2138  )<br>         13           C   tau( 13)=( -0.2395 -0.1740  0.1069  )<br>         14           C   tau( 14)=( -0.1478 -0.2565  0.1069  )<br>
         15           C   tau( 15)=( -0.0915 -0.2816  0.2138  )<br>         16           C   tau( 16)=(  0.0312 -0.2944  0.2138  )<br>         17           C   tau( 17)=(  0.0915 -0.2816  0.1069  )<br>         18           C   tau( 18)=(  0.1983 -0.2198  0.1069  )<br>
         19           C   tau( 19)=(  0.2395 -0.1740  0.2138  )<br>         20           C   tau( 20)=(  0.2896 -0.0613  0.2138  )<br><br>     nr1s                      =          120<br>     nr2s                      =          120<br>
     nr3s                      =           27<br>     nrx1s                     =          120<br>     nrx2s                     =          120<br>     nrx3s                     =           27<br>     nr1                       =          120<br>
     nr2                       =          120<br>     nr3                       =           27<br>     nrx1                      =          120<br>     nrx2                      =          120<br>     nrx3                      =           27<br>
<br> _______________________________<br>  Radii of nonlocal spheres: <br><br>     type       ibeta     ang. mom.          radius (a_0 units)<br>          C       1         0                    0.0593<br>----- General information -----<br>
<br>----- Complex band structure calculation -----<br><br>     nrx                       =          120<br>     nry                       =          120<br>     nz1                       =           11<br><br><br>     energy0               =         4.0E+00<br>
     denergy               =        -1.0E-01<br>     nenergy               =          5<br>     ecut2d                =         7.5E+01<br>     ewind                 =         3.0E+00<br>     epsproj               =         1.0E-04<br>
<br><br>     number of k_|| points=    1<br>                       cryst. coord. <br>        k(    1) = (   0.0000000   0.0000000), wk =   1.0000000<br>----- Information about left lead ----- <br><br>     nocros                   =           10<br>
     noins                    =           10<br>     norb                     =           30<br>     norbf                    =           30<br>     nrz                      =           27<br><br>      iorb      type   ibeta   ang. mom.   m       position (a_0)<br>
        1        1       1        0        1   taunew(   1)=(  0.2395  0.1740  0.0000)<br>        2        1       1        0        1   taunew(   2)=(  0.1478  0.2565  0.0000)<br>        3        1       1        0        1   taunew(   3)=( -0.0915  0.2816  0.0000)<br>
        4        1       1        0        1   taunew(   4)=( -0.1983  0.2198  0.0000)<br>        5        1       1        0        1   taunew(   5)=( -0.2960  0.0000  0.0000)<br>        6        1       1        0        1   taunew(   6)=( -0.2703 -0.1207  0.0000)<br>
        7        1       1        0        1   taunew(   7)=( -0.0915 -0.2816  0.0000)<br>        8        1       1        0        1   taunew(   8)=(  0.0312 -0.2944  0.0000)<br>        9        1       1        0        1   taunew(   9)=(  0.2395 -0.1740  0.0000)<br>
       10        1       1        0        1   taunew(  10)=(  0.2896 -0.0613  0.0000)<br>       11        1       1        0        1   taunew(  11)=(  0.2960  0.0000  0.1069)<br>       12        1       1        0        1   taunew(  12)=(  0.2703  0.1207  0.1069)<br>
       13        1       1        0        1   taunew(  13)=(  0.0915  0.2816  0.1069)<br>       14        1       1        0        1   taunew(  14)=( -0.0312  0.2944  0.1069)<br>       15        1       1        0        1   taunew(  15)=( -0.2395  0.1740  0.1069)<br>
       16        1       1        0        1   taunew(  16)=( -0.2896  0.0613  0.1069)<br>       17        1       1        0        1   taunew(  17)=( -0.2395 -0.1740  0.1069)<br>       18        1       1        0        1   taunew(  18)=( -0.1478 -0.2565  0.1069)<br>
       19        1       1        0        1   taunew(  19)=(  0.0915 -0.2816  0.1069)<br>       20        1       1        0        1   taunew(  20)=(  0.1983 -0.2198  0.1069)<br>       21        1       1        0        1   taunew(  21)=(  0.2395  0.1740  0.2138)<br>
       22        1       1        0        1   taunew(  22)=(  0.1478  0.2565  0.2138)<br>       23        1       1        0        1   taunew(  23)=( -0.0915  0.2816  0.2138)<br>       24        1       1        0        1   taunew(  24)=( -0.1983  0.2198  0.2138)<br>
       25        1       1        0        1   taunew(  25)=( -0.2960  0.0000  0.2138)<br>       26        1       1        0        1   taunew(  26)=( -0.2703 -0.1207  0.2138)<br>       27        1       1        0        1   taunew(  27)=( -0.0915 -0.2816  0.2138)<br>
       28        1       1        0        1   taunew(  28)=(  0.0312 -0.2944  0.2138)<br>       29        1       1        0        1   taunew(  29)=(  0.2395 -0.1740  0.2138)<br>       30        1       1        0        1   taunew(  30)=(  0.2896 -0.0613  0.2138)<br>
    k slab    z(k)  z(k+1)     crossing(iorb=1,norb)<br>    1   0.0000 0.0079 0.0079   111111111100000000000000000000<br>    2   0.0079 0.0158 0.0079   111111111100000000000000000000<br>    3   0.0158 0.0238 0.0079   111111111100000000000000000000<br>
    4   0.0238 0.0317 0.0079   111111111100000000000000000000<br>    5   0.0317 0.0396 0.0079   111111111100000000000000000000<br>    6   0.0396 0.0475 0.0079   111111111100000000000000000000<br>    7   0.0475 0.0554 0.0079   111111111111111111110000000000<br>
    8   0.0554 0.0633 0.0079   111111111111111111110000000000<br>    9   0.0633 0.0713 0.0079   000000000011111111110000000000<br>   10   0.0713 0.0792 0.0079   000000000011111111110000000000<br>   11   0.0792 0.0871 0.0079   000000000011111111110000000000<br>
   12   0.0871 0.0950 0.0079   000000000011111111110000000000<br>   13   0.0950 0.1029 0.0079   000000000011111111110000000000<br>   14   0.1029 0.1108 0.0079   000000000011111111110000000000<br>   15   0.1108 0.1188 0.0079   000000000011111111110000000000<br>
   16   0.1188 0.1267 0.0079   000000000011111111110000000000<br>   17   0.1267 0.1346 0.0079   000000000011111111110000000000<br>   18   0.1346 0.1425 0.0079   000000000011111111110000000000<br>   19   0.1425 0.1504 0.0079   000000000011111111110000000000<br>
   20   0.1504 0.1583 0.0079   000000000011111111111111111111<br>   21   0.1583 0.1663 0.0079   000000000011111111111111111111<br>   22   0.1663 0.1742 0.0079   000000000000000000001111111111<br>   23   0.1742 0.1821 0.0079   000000000000000000001111111111<br>
   24   0.1821 0.1900 0.0079   000000000000000000001111111111<br>   25   0.1900 0.1979 0.0079   000000000000000000001111111111<br>   26   0.1979 0.2058 0.0079   000000000000000000001111111111<br>   27   0.2058 0.2138 0.0079   000000000000000000001111111111<br>
<br>        k(    1) = (   0.0000000   0.0000000), wk =   1.0000000<br><br> ngper, shell number =         2809         299<br>####################################################################################<br>the output file stopped  there, and I couldn't see the process. Maybe it takes long time cause I found it took 1 hour to calculate a transmission.<br>
I don't quite understand the parameters setting, I have adjusted the ewind, epsproj, nzl, according to the postings on this forum. However, <br>the result seemed not change. <br><br>I appreciate everyone who could give me some advice.<br>
Thank you!<br><br>Regards.<br><br>Chengyu Yang<br>Material Science and Engineering,<br> University of Central Florida, USA<br><br><br>     <br>
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