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Ab initio Calculations Using Q-Espresso Code

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How to download and install PWTK package

Abderrahmane REGGAD November 25, 2024

1 What is PWTK

PWTK stands for PWSCF TOOLKIT.

PWTK is a Tcl scripting interface for Quantum ESPRESSO, aiming at providing a flexible and productive framework.

With PWTK, one can automate calculations and glue together different computational tasks, where outputs of preceding calculations serve as inputs for subsequent calculations.

(PWTK, standing for PWscf ToolKit, got its name from the consideration that it initially supported only the PWscf subset of Quantum ESPRESSO programs. Moreover, the name “Quantum ESPRESSO” did not yet exist at the time the PWTK project was initiated.)

 

2 Simple example

Here is a simple example: a comparison between the pw.x input file and the corresponding PWTK script.

pw.x input file: scf.si.in PWTK script file: si.pwtk 
 &CONTROL
  calculation = 'scf'
       outdir = 'Si_example/'
   pseudo_dir = '/home/tone/pw/pseudo/'
 /

 &SYSTEM
        ibrav = 2
    celldm(1) = 10.2
          nat = 2
         ntyp = 1
      ecutwfc = 18.0
      ecutrho = 72.0
 /

 &ELECTRONS
     conv_thr = 1d-7
 /

ATOMIC_SPECIES
   Si  1.00  Si.vbc 

ATOMIC_POSITIONS alat 
   Si    0.00  0.00  0.00    
   Si    0.25  0.25  0.25    

K_POINTS automatic 
   4 4 4   1 1 1

CONTROL {
  calculation = 'scf' 
       outdir = 'Si_example/'
   pseudo_dir = '/home/tone/pw/pseudo/'
} 
 
SYSTEM {
        ibrav = 2
    celldm(1) = 10.2
          nat = 2
         ntyp = 1
      ecutwfc = 18.0 
      ecutrho = 4*18.0 
}

ELECTRONS {
      conv_thr = 1d-7
}

ATOMIC_SPECIES {
   Si  1.00  Si.vbc 
}
ATOMIC_POSITIONS alat {
   Si    0.0   0.0   0.0
   Si    1/4   1/4   1/4
}
K_POINTS automatic {
  4 4 4   1 1 1 
}

runPW scf.si.in
This calculation is run as: This calculation is run as: 
pw.x < scf.si.in > scf.si.out &

pwtk si.pwtk > si.log &

The syntax of the PWTK scripts is similar to QE input file, but notice that both Fortran namelists (e.g. &CONTROL) and cards (e.g. ATOMIC_SPECIES) are enclosed with curly braces (e.g. CONTROL { ... }).

The last line of the above PWTK script, runPW scf.si.in, requests the pw.x calculation. Upon execution, PWTK will:

  • construct the scf.si.in input file (the output will be written to scf.si.out),
  • create the outdir temporary directory if the directory does not exist
  • run the pw.x calculation.

At a simplistic level of the above example, there is no advantage of using PWTK, but the advantage becomes evident once multiple calculations are performed (see example 1.5).

For detailed information check this link PWTK

How to install required Tcl packages in GNU/Linux

For Debian-based linux distros:

sudo apt install tcl tcllib tcl-tclreadline tcl-thread

3 Downloading

 Version 3.2
(Release date: 11 November 2024, release notes)

QE-emacs modes

To make the writing of PWTK scripts a bit easier, consider installing QE-emacs-modes.

 

4 Installing

No compilation is required. Just download and untar the tarball, and add the location of the PWTK package (its root directory) to your PATH.

You can also download the package using the following command

$ wget http://pwtk.ijs.si/download/pwtk-3.0.tar.gz
$ sudo tar zxvf pwtk-3.0.tar.gz

 Then open the ~/.bashrc file with editor (say emacs) and add the following snippet: 

export PATH=/home/alkhawarizmi/abinitio/pwtk-3.2:$PATH

 


 References:

http://www-k3.ijs.si/kokalj/internal/pwtk-3.0rc12/doc/tutorial.html 

https://pwtk.ijs.si/install.html

https://pwtk.ijs.si/download.html 

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