# A Virtual Machine (based on Quantum Mobile) to automatically compute Wannier functions

We provide here a Virtual Machine Appliance (i.e., an importable Virtual 
Machine) to be run with the VirtualBox software.

The Virtual Machine contains a fully working installation of AiiDA, 
Quantum Espresso, Wannier90, and the workflows to compute automatically 
Wannier functions using the SCDM method.

## How to use the VM

### Download and start the Virtual Machine
- Download/get the virtual machine image (file with '.ova' extension in the
  archive entry)
- Install Virtual Box 6.0.0 or later from www.virtualbox.org
- Import the virtual machine image into Virtualbox (this will require about 
  10GB of disk space), using `File => Import Appliance` inside the 
  Virtualbox software.
- Configure the hardware settings of your virtual machine:
  - select the imported VM in VirtualBox
  - press on the `Settings` button
  - choose the `System` tab
  - under `Motherboard` give at leat 10GB of RAM (if you have them in your 
    machine). Less RAM, beside making the machine quite slow, might not be 
    enough for the quantum simulations to run
  - under `Processor`, give 2 CPUs (or 3 for a bit better usability)
- **NOTE**: often the user interface becomes *very* slow after a few minutes of
  usage (the terminal works fine, but dragging windows can start to take tens of
  seconds). You can follow the next step, that seems to provide a good workaround
  solving the issue: under the `Display` tab, change the `Graphics Controller`
  value to `VMSVGA` (this might be fixed in recent versions of VirtualBox)
- in any case, make sure that 3D acceleration is active in the `Display` tab
- Start the virtual machine.
  (Note: when the virtual machine starts, if needed, you can use the following
  credentials: username: `max`, password: `moritz`)

### Run your simulation
Follow the instructions in the file `tutorial-with-screenshots-VM.pdf`, that
also contains screenshots guiding you through all steps.