To test pw.x, edit "environment_variables" in the QE directory, go to the PW/example directory, and execute
$ run_all_examples
or in one of example* directories, execute
run_example
to see how the code works.
Let us set the path to pw.x as
PW_DIR=${HOME}/QE/src/qe-6.2.1/bin/pw.x
and
PW=${PW_DIR}/pw.x
(the path depends on your environment and version of QE) Let us use the following input file ("si.scf.in") as an example
&control calculation = 'scf' restart_mode = 'from_scratch', pseudo_dir = '/home/hamada/QE/pseudo/', outdir = './tmp' prefix = 'si' / &system ibrav = 2 celldm(1) = 10.1555 nat = 2 ntyp = 1 ecutwfc = 25.0 nbnd = 8 / &electrons diagonalization = 'david' conv_thr = 1.0e-10 mixing_beta = 0.2 / ATOMIC_SPECIES Si 0.000 Si.pz-vbc.UPF ATOMIC_POSITIONS (crystal) Si 0.0000 0.0000 0.0000 Si 0.2500 0.2500 0.2500 K_POINTS (automatic) 4 4 4 1 1 1
and run pw.x by executing
mpirun -np 4 $PW < si.scf.in > si.scf.out
Note the command and options change depending on the environment.