[Pw_forum] the efficiency problem of transmission calculation by pwcond.x

[Wang Qinjing]

Hi all

I am doing transmission calculation by pwcond.x. I have 2 question about the efficiency of it.

(1) The most severe problem was that I felt the transmission calculation by pwcond.x was too 
slow. As an example, the system contains a 6-atom lead and about 100-atom scattering region. T
he kx and ky was 8 and 1 respectively. The input file for pwcond.x is as follows:

----------------
&inputcond
    outdir='./outdir',
    prefixl='lead'
    prefixs='cen',
    tran_file='trans.0'
    ikind = 1,
    energy0=2.0d0,
    denergy=-0.2d0
    ewind=4.d0,
    epsproj=1.d-7,
    nz1 = 10,
 /
   5
   0.0000000   0.0000000   0.2500000
   0.1250000   0.0000000   0.5000000
   0.2500000   0.0000000   0.5000000
   0.3750000   0.0000000   0.5000000
  -0.5000000   0.0000000   0.2500000
   21
------------------

It took about 1 hour to get a transmission value for a certain energy on a 8-node parallel cluster
with 1 G memory, 2.5 GHz CPU and infiniband. Is it a reasonable one?

(2) I notice that the time needed for the transmission is linear proportional to the number of 
energy points. That means if the time needed for a single energy point is 1 hour, it will take 
20 hours for 20 energy points. This is different with some other scientific softwares. Is it natural
for pwcond.x?

Thank you in advance

Best wishes

Wang


------------------------------------
王秦镜，复旦大学物理系研究生
Wang Qinjing, Physics Department, 
Fudan University
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