double-click.txt

Why nothing happens when I double click on feenox.exe?

Because by design, FeenoX does not have a Graphical User Interface.
Instead, it works like a transfer function between one or more input
files and zero or more output files:

                                 +------------+
     mesh (*.msh)  }             |            |             { terminal
     data (*.dat)  } input ----> |   FeenoX   |----> output { data files
     input (*.fee) }             |            |             { post (vtk/msh)
                                 +------------+

Recall that FeenoX is designed as a cloud-first tool, and “the cloud”
runs on Unix (essentially GNU/Linux) so FeenoX is based on the Unix
philosophy. In this world, programs act like filters (i.e. transfer
functions). They are executed from a command-line terminal. So instead
of “double clicking” the executable, one has to open a terminal and
execute it there. Without any arguments it says how to use it:

    > feenox.exe
    FeenoX v0.2.14-gbbf48c9
    a free no-fee no-X uniX-like finite-element(ish) computational engineering tool

    usage: feenox [options] inputfile [replacement arguments] [petsc options]

      -h, --help         display options and detailed explanations of command-line usage
      -v, --version      display brief version information and exit
      -V, --versions     display detailed version information

    Run with --help for further explanations.
    >

With -h it gives more information:

    > feenox.exe -h
    usage: feenox [options] inputfile [replacement arguments] [petsc options]

      -h, --help         display options and detailed explanations of command-line usage
      -v, --version      display brief version information and exit
      -V, --versions     display detailed version information

      --progress         print ASCII progress bars when solving PDEs
      --mumps            ask PETSc to use the direct linear solver MUMPS
      --linear           force FeenoX to solve the PDE problem as linear
      --non-linear       force FeenoX to solve the PDE problem as non-linear

    Instructions will be read from standard input if “-” is passed as
    inputfile, i.e.

        $ echo 'PRINT 2+2' | feenox -
        4

    The optional [replacement arguments] part of the command line mean that
    each argument after the input file that does not start with an hyphen
    will be expanded verbatim in the input file in each occurrence of $1,
    $2, etc. For example

        $ echo 'PRINT $1+$2' | feenox - 3 4
        7

    PETSc and SLEPc options can be passed in [petsc options] as well, with
    the difference that two hyphens have to be used instead of only once.
    For example, to pass the PETSc option -ksp_view the actual FeenoX
    invocation should be

        $ feenox input.fee --ksp_view

    See https://www.seamplex.com/feenox/examples for annotated examples.

    Report bugs at https://github.com/seamplex/feenox/issues
    Ask questions at https://github.com/seamplex/feenox/discussions
    Feenox home page: https://www.seamplex.com/feenox/
    >

It is explained there that the main input file has to be given as the
first argument. So go to the tests or examples directory, find a test
you like and run it:

    > cd tests
    > feenox parallelepiped.fee
    0.000295443
    >

In any case, recall once again that FeenoX is a cloud-first tool, and
Windows is not cloud-friendly, let alone cloud-first. It is time to
re-think what you expect from a finite-element(ish) tool. If you still
need a GUI, please check CAEplex.

Try to avoid Windows as much as you can. The binaries are provided as
transitional packages for people that for some reason still use such an
outdated, anachronous, awful and invasive operating system. They are
compiled with Cygwin and have no support whatsoever. Really, really, get
rid of Windows ASAP.

  “It is really worth any amount of time and effort to get away from
  Windows if you are doing computational science.”

  https://lists.mcs.anl.gov/pipermail/petsc-users/2015-July/026388.html