quantum-espresso/examples

These are basic instructions on how to run the examples contained
within the "examples" directory of the PWscf distribution (same
directory where this README file should be).

1) Edit the file "environment_variables" in the "examples" directory
   and set the following variables as needed:

     BIN_DIR = path of compiled PWscf executables
     PSEUDO_DIR = path of pseudopotentials required by the examples
     TMP_DIR = temporary directory to be used by the examples

   If you have downloaded the full PWscf distribution, you may set
   BIN_DIR = $TOPDIR/bin and PSEUDO_DIR = $TOPDIR/pseudo, where
   $TOPDIR is the root of the PWscf source tree.  (Accordingly, the
   examples directory should be $TOPDIR/examples.)  To have the
   executables in $TOPDIR/bin, you must have run "make links" after
   compiling.

   TMP_DIR must be a temporary storage area you have read/write access
   to, is large enough to host the temporary files produced by the
   PWscf programs, and possibly offers high I/O performance (no NFS).

2) Check that the directory specified by PSEUDO_DIR contains the
   following files:    

     Al.vbc.UPF, As.gon.UPF, Cu.pz-d-rrkjus.UPF, CUS.RRKJ3.UPF,
     CuUS.RRKJ3.UPF, Fe.pz-nd-rrkjus.UPF, Ni.pbe-nd-rrkjus.UPF,
     NiUS.RRKJ3.UPF, O.LDA.US.RRKJ3i.UPF, Si.vbc.UPF, H.vbc.UPF,
     Pb.vdb.UPF, O.vdb.UPF, Ti.vdb.UPF

   If any of these are missing, you may not be able to run some of the
   examples.  You can download the missing ones from the web at the
   address: http://www.pwscf.org/pseudo.htm

3) ONLY FOR PARALLEL ARCHITECTURES: to run parallel jobs, your machine
   may require that executable programs be run through a driver
   program such as "poe" or "mpiexec".  For example on an IBM SP4,
   pw.x could be run on 4 processors this way:

     poe pw.x -procs 4 < file.in > file.out

   If this is the case, you must edit again the file
   "environment_variables" and set the PARA_PREFIX and PARA_POSTFIX
   variables as needed.  Parallel executables will be run by a command
   like this:

     $PARA_PREFIX pw.x $PARA_POSTFIX < file.in > file.out

   Thus, in the example above, you should set PARA_PREFIX="poe" and
   PARA_POSTFIX="-procs 4".

   Also, if the machine does not support interactive use, you should
   write the commands specified below in a batch script, and run it
   through the batch queuing system installed on that machine.

4) To run a specific example: cd to the corresponding directory (i.e.,
   example01) and execute:

     ./run_example

   A subdirectory "results" is produced which collects the input and
   output files generated by the calculation.  The results can be
   compared to those in the "reference" subdirectory coming with this
   distribution.

   The reference results where generated on a 1.7 GHz Pentium IV using
   Intel compiler (ifc) v.6 and MKL libraries v.5.1.
   On different architectures the precise numbers could be slightly
   different (in particular if different FFT dimensions are
   automatically selected) but not in any significant way.

5) To check the generated results against those in the "reference"
   directory coming with this distribution, execute:

     ./check_example example_dir

   from the "examples" directory.
   "example_dir" is the directory of the example that you want to
   check (i.e., ./check_example example01).  You can specify multiple
   directories.

   Note: at the moment "check_example" is in early development and
   known not to work in many cases, in particular you should only run
   it on examples 1 to 4.

6) To run all the examples in one go, execute:

     ./run_all_examples

   from the "examples" directory.

7) To restore the examples subdirectories to their original content,
   run the "make_clean" script.  For each example, this removes the
   subdirectory "results" together with all files apart from "README",
   and "run_example".  If additional subdirectories have been created
   they are not deleted.

-----------------------------------------------------------------------

                   LIST AND CONTENT OF THE EXAMPLES

example01:
    This example shows how to use pw.x to calculate the total energy
    and the band structure of four simple systems: Si, Al, Cu, Ni.

example02:
    This example shows how to use pw.x and ph.x to calculate phonon
    frequencies at Gamma and X for Si in diamond structure.

example03:
    This example shows how to use pw.x to compute the equilibrium
    geometry of a simple molecule, CO, and of an Al (001) slab.
    In the latter case the relaxation is performed in two ways:
    1) using the quasi-Newton BFGS algorithm
    2) using a damped dynamics algorithm.

example04:
    This example shows how to use pw.x to perform molecular dynamics
    for 2- and 8-atom cells of Si starting with compressed bonds along
    (111).

example05:
    This example shows how to use pw.x and postprocessing codes to
    make a contour plot in the [110] plane of the charge density for
    Si, and to plot the band structure of Si.

example06:
    This example shows how to calculate interatomic force constants in
    real space for AlAs in zincblende structure.

example07:
    This example shows how to calculate electron-phonon interaction
    coefficients at X for fcc Al.

example08:
    This example shows how to use pw.x to calculate the DOS of Ni.

example09:
    This example shows how to use pw.x and phcg.x to calculate the
    normal modes of a molecule (SiH4) at Gamma.

example10:
    This example shows how to calculate the polarization via Berry
    Phase in PBTiO3 (contributed by the Vanderbilt Group in Rutgers
    University).

example11:
    This example shows how to calculate the total energy of an
    isolated atom in a supercell with fixed occupations.
    Two examples: LDA energy of Al and sigma-GGA energy of O.

example12:
    This example shows how to use pw.x and pwcond.x to calculate the
    complex bands and the transmission coefficient of an open quantum
    system.

example13:
    This example shows how to use pw.x to calculate the total energy
    and the band structure of four simple systems in the non-collinear
    case: Fe, Cu, Ni, O.

example14:
    This example shows how to use pw.x, ph.x and d3 to calculate the
    third-order expansion coefficients of the total energy of Si.

example15:
    This example shows how to use pw.x, ph.x, and ram.x to calculate
    the Raman tensor for AlAs.

example16:
    This example shows a calculation of STM maps.

example17:
    This example shows how to use pw.x to calculate the minimum energy
    path (MEP) in the collinear proton transfer reaction H2+H => H+H2.

example18:
    This example shows how to use cp.x to perform molecular dynamics
    simulation of SiO2.

example19:
    This example shows how to use par2.x to perform molecular dynamics
    simulation of H2O.

example20:
    This example shows how to use par2.x to perform molecular dynamics
    simulation of NH3.

example21:
    This example shows how to use par2.x to perform molecular dynamics
    simulation of medium to large systems.