### Build QE with CMake (CPU)

Source: https://context7.com/qef/q-e/llms.txt

Recommended for complex configurations. This example shows a CPU build using CMake, specifying compilers, installation prefix, and enabling Scalapack and HDF5.

```bash
mkdir build && cd build

# CPU build
cmake -DCMAKE_Fortran_COMPILER=mpif90 \
      -DCMAKE_C_COMPILER=mpicc \
      -DCMAKE_INSTALL_PREFIX=/opt/qe \
      -DQE_ENABLE_SCALAPACK=ON \
      -DQE_ENABLE_HDF5=ON \
      ..
make -j8
make install
# Executables in build/bin/ or /opt/qe/bin/ after install
```

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

### Install Quantum ESPRESSO using make

Source: https://gitlab.com/qef/q-e/-/blob/develop/README.md

Use this method for a quick installation on CPU-based machines. Ensure you are in the directory containing the installation files. 'make -jN' can be used for parallel compilation.

```bash
./configure [options]
make all
```

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

### Install GUI Directories

Source: https://gitlab.com/qef/q-e/-/blob/develop/GUI/CMakeLists.txt

Installs the Guib, PWgui, and QE-modes directories to the share/GUI location.

```cmake
install(DIRECTORY Guib PWgui QE-modes
    DESTINATION
        share/GUI
    USE_SOURCE_PERMISSIONS)
```

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

### Install README File

Source: https://gitlab.com/qef/q-e/-/blob/develop/GUI/CMakeLists.txt

Installs the README file to the share/GUI directory.

```cmake
install(FILES README
    DESTINATION
        share/GUI)
```

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

### Configure QEHeat Installation

Source: https://gitlab.com/qef/q-e/-/blob/develop/QEHeat/examples/README.md

Run the configure script to set up the build environment for QEHeat. This is a standard step in Quantum Espresso installations.

```bash
> ./configure
```

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

### Autopilot Example Syntax

Source: https://gitlab.com/qef/q-e/-/blob/develop/CPV/Doc/autopilot_guide.md

An example demonstrating how to configure dynamic parameter changes for temperature, timestep, and save interval at specific simulation steps.

```plaintext
AUTOPILOT
  ON_STEP = 200 : tempw = 500.0
  ON_STEP = 200 : dt = 3.0
  ON_STEP = 250 : ISAVE = 50
ENDRULES
```

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

### Install Phonon Libraries and Executables

Source: https://gitlab.com/qef/q-e/-/blob/develop/PHonon/CMakeLists.txt

Installs the necessary phonon libraries and all defined phonon executables using the qe_install_targets macro.

```cmake
qe_install_targets(
    # Libraries
    qe_phonon_ph
    qe_phonon_phaux
    qe_phonon_gamma
    qe_phonon_fd
    # Executables
    ${PH_EXE_TARGETS})
```

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

### Install COUPLE Targets

Source: https://gitlab.com/qef/q-e/-/blob/develop/COUPLE/CMakeLists.txt

Installs the built targets, including the 'qe_couple' library and its associated files, to the appropriate locations based on the CMake installation prefix.

```cmake
qe_install_targets(qe_couple)
```

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

### Example INI Configuration File

Source: https://gitlab.com/qef/q-e/-/blob/develop/test-suite/testcode/docs/configuration_files.md

Demonstrates the ini format for configuration files with sections and variables.

```ini
[section_1]
a = 2
b = test_option

[section_2]
v = 4.5
hello = world
```

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

### Install HDF5 5.10.4

Source: https://gitlab.com/qef/q-e/-/blob/develop/test-suite/buildbot/Udine_farm/README.txt

Steps to download, configure, build, and install HDF5 version 5.10.4. Ensure the configure script uses the correct prefix and enables Fortran support if needed.

```bash
wget https://support.hdfgroup.org/ftp/HDF5/releases/hdf5-1.10/hdf5-1.10.4/src/hdf5-1.10.4.tar.gz
./configure --prefix=/home/buildbot/local/hdf5-104-gcc102 --enable-fortran
make -j 4
make install
```

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

### Execute Post-Installation Command

Source: https://gitlab.com/qef/q-e/-/blob/develop/GUI/CMakeLists.txt

Executes the 'make init' command within the PWgui directory after installation. Output and errors are suppressed.

```cmake
install(CODE
    "execute_process(
        COMMAND make init
        WORKING_DIRECTORY ${CMAKE_INSTALL_PREFIX}/share/GUI/PWgui
        OUTPUT_QUIET
        ERROR_QUIET)")
```

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

### Install QE Targets

Source: https://gitlab.com/qef/q-e/-/blob/develop/Modules/CMakeLists.txt

Installs the 'qe_modules' and 'qe_modules_c' targets. This makes the built libraries available for use by other projects or for deployment.

```cmake
qe_install_targets(qe_modules qe_modules_c)
```

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

### cppp.x Input Namelist Example

Source: https://gitlab.com/qef/q-e/-/blob/develop/CPV/Doc/INPUT_CPPP.html

This is an example of the &INPUTPP namelist used to configure the cppp.x utility. Specify parameters to control output, file handling, and data processing.

```fortran
&INPUTPP
  ...
  cppp_input_parameter
  ...
/

```

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

### Install Quantum ESPRESSO using CMake

Source: https://gitlab.com/qef/q-e/-/blob/develop/README.md

Recommended for versions 3.14 or later. It is strongly advised to specify Fortran and C compilers using CMAKE_Fortran_COMPILER and CMAKE_C_COMPILER. Parallel compilation is supported with 'make -jN'. The 'make install' command requires CMAKE_INSTALL_PREFIX to be set.

```bash
mkdir ./build
cd ./build
cmake -DCMAKE_Fortran_COMPILER=mpif90 -DCMAKE_C_COMPILER=mpicc [-DCMAKE_INSTALL_PREFIX=/path/to/install] ..
make [-jN]
[make install]
```

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

### Install pp.py Script

Source: https://gitlab.com/qef/q-e/-/blob/develop/EPW/CMakeLists.txt

Installs the pp.py Python script to the bin directory, renaming it to epw_pp.py.

```cmake
install(PROGRAMS bin/pp.py TYPE BIN RENAME epw_pp.py)
```

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

### Install PP targets

Source: https://gitlab.com/qef/q-e/-/blob/develop/PP/CMakeLists.txt

Installs the defined PP libraries and executables. This command makes the compiled targets available for use after the build process.

```cmake
qe_install_targets(
    # Libraries
    qe_pp
    # Executables
    ${PP_EXE_TARGETS})
```

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

### Install GWW Libraries and Executables

Source: https://gitlab.com/qef/q-e/-/blob/develop/GWW/CMakeLists.txt

Installs the GWW module's libraries and executables to the appropriate locations in the build system.

```cmake
qe_install_targets(
    # Libraries
    qe_gww
    qe_gww_pw4gww
    qe_gww_bse
    qe_gww_head
    qe_gww_minpack
    qe_gww_simple
    qe_gww_simplebse
    qe_gww_simpleip
    # Executables
    ${GWW_EXE_TARGETS})
```

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

### Configure Quantum ESPRESSO with Specific CUDA Details

Source: https://gitlab.com/qef/q-e/-/blob/develop/README_GPU.md

Example of configuring Quantum ESPRESSO using CUDA_HOME, compute capability 70, and runtime version 11.0.

```bash
./configure --with-cuda=$CUDA_HOME --with-cuda-cc=70 --with-cuda-runtime=11.0
```

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

### Build QE with configure + make

Source: https://context7.com/qef/q-e/llms.txt

Standard CPU build using the traditional `configure` script. Ensure MPI and optional libraries like Scalapack and HDF5 are correctly specified.

```bash
# Configure with MPI and optional libraries
./configure --enable-parallel \
            --with-scalapack=yes \
            --with-hdf5=/path/to/hdf5 \
            MPIF90=mpif90 CC=mpicc

make all -j8          # builds pw.x, cp.x, ph.x, pp.x, neb.x, ...
# Binaries linked under bin/
ls bin/
# pw.x  cp.x  ph.x  pp.x  dos.x  projwfc.x  bands.x  neb.x  epw.x  hp.x ...
```

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

### Data Tagging Example

Source: https://gitlab.com/qef/q-e/-/blob/develop/test-suite/testcode/docs/verification.md

Use a data tag to identify specific lines in output files for comparison. The first numerical entry on lines starting with the tag is validated against the benchmark.

```text
[QA] Energy = 1.23456 eV
```

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

### Install KS Solver Targets

Source: https://gitlab.com/qef/q-e/-/blob/develop/KS_Solvers/CMakeLists.txt

Installs all defined KS solver libraries as targets in the build system. This makes them available for use by other parts of the project or for installation.

```cmake
qe_install_targets(
    qe_kssolver_davidson
    qe_kssolver_davidsonrci
    qe_kssolver_cg
    qe_kssolver_paro
    qe_kssolver_dense
    qe_kssolver_rmmdiis
    qe_kssolver_direct)
```

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

### Install LAX Target

Source: https://gitlab.com/qef/q-e/-/blob/develop/LAXlib/CMakeLists.txt

Installs the LAX library target.

```cmake
qe_install_targets(qe_lax)
```

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

### Install TDDFPT Targets

Source: https://gitlab.com/qef/q-e/-/blob/develop/TDDFPT/CMakeLists.txt

Installs the TDDFPT library and all defined executables.

```cmake
qe_install_targets(
    # Libraries
    qe_tddfpt
    # Executables
    ${TDDFPT_EXE_TARGETS})
```

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

### Install EPW Targets

Source: https://gitlab.com/qef/q-e/-/blob/develop/EPW/CMakeLists.txt

Installs various EPW executables and libraries to the appropriate locations.

```cmake
qe_install_targets(
    # Libraries
    qe_epw
    # Exacutables
    qe_epw_exe
    qe_epw_nscf2supercond_exe
    qe_zg_exe
    qe_zg_disca_exe
    qe_zg_pp_disca_exe
    qe_zg_bands_unfold_exe
    qe_zg_pp_spctrlfn_exe
    qe_zg_epsilon_Gaus_exe)
```

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

### Set Runtime Environment Variables for QE

Source: https://context7.com/qef/q-e/llms.txt

This example demonstrates setting key environment variables that control the runtime behavior of Quantum ESPRESSO executables, such as scratch directory, pseudopotential location, and OpenMP thread count.

```bash
# Directory for scratch/temporary files (overrides outdir in input if set)
export ESPRESSO_TMPDIR=/scratch/$USER/qe_tmp

# Directory to search for pseudopotential files (overrides pseudo_dir in input)
export ESPRESSO_PSEUDO=/opt/pseudo/SSSP

# Number of OpenMP threads per MPI rank
export OMP_NUM_THREADS=2

# Example: run pw.x using env vars
mkdir -p $ESPRESSO_TMPDIR
mpirun -np 8 pw.x -i silicon_scf.in > silicon_scf.out

```

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

### Install DFT-D3 Targets

Source: https://gitlab.com/qef/q-e/-/blob/develop/dft-d3/CMakeLists.txt

Installs the defined DFT-D3 targets, making them available for use in other parts of the project or for deployment.

```cmake
qe_install_targets(qe_dftd3)
```

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

### CP Simulation Input Example

Source: https://gitlab.com/qef/q-e/-/blob/develop/CPV/Doc/user_guide.md

Configuration for a CP simulation of a Benzene Molecule. This includes control, system, electrons, ions, and cell parameters, along with atomic species and positions.

```fortran
&control
   title = 'Benzene Molecule',
   calculation = 'cp',
   restart_mode = 'from_scratch',
   ndr = 51,
   ndw = 51,
   nstep = 100,
   iprint = 10,
   isave = 100,
   tstress = .TRUE.,
   tprnfor = .TRUE.,
   dt    = 5.0d0,
   etot_conv_thr = 1.d-9,
   ekin_conv_thr = 1.d-4,
   prefix = 'c6h6',
   pseudo_dir='/scratch/benzene/',
   outdir='/scratch/benzene/Out/'
 /
 &system
    ibrav = 14,
    celldm(1) = 16.0,
    celldm(2) = 1.0,
    celldm(3) = 0.5,
    celldm(4) = 0.0,
    celldm(5) = 0.0,
    celldm(6) = 0.0,
    nat = 12,
    ntyp = 2,
    nbnd = 15,
    ecutwfc = 40.0,
    nr1b= 10, nr2b = 10, nr3b = 10,
    input_dft = 'BLYP'
 /
 &electrons
    emass = 400.d0,
    emass_cutoff = 2.5d0,
    electron_dynamics = 'sd'
 /
 &ions
    ion_dynamics = 'none'
 /
 &cell
    cell_dynamics = 'none',
    press = 0.0d0,
  /
  ATOMIC_SPECIES
  C 12.0d0 c_blyp_gia.pp
  H 1.00d0 h.ps
  ATOMIC_POSITIONS (bohr)
  C     2.6 0.0 0.0
  C     1.3 -1.3 0.0
  C    -1.3 -1.3 0.0
  C    -2.6 0.0 0.0
  C    -1.3 1.3 0.0
  C     1.3 1.3 0.0
  H     4.4 0.0 0.0
  H     2.2 -2.2 0.0
  H    -2.2 -2.2 0.0
  H    -4.4 0.0 0.0
  H    -2.2 2.2 0.0
  H     2.2 2.2 0.0

```

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

### Run FFT Test Program

Source: https://gitlab.com/qef/q-e/-/blob/develop/FFTXlib/README.md

Execute the compiled FFT test program using mpirun. The example demonstrates setting parameters like energy cutoff, lattice parameter, number of bands, and number of task groups.

```bash
mpirun -np 4 ./fft_test.x -ecutwfc 80 -alat 20  -nbnd 128 -ntg 4
```

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

### Install LR Modules Target

Source: https://gitlab.com/qef/q-e/-/blob/develop/LR_Modules/CMakeLists.txt

Installs the 'qe_lr_modules' target. This makes the compiled library available for use by other parts of the project or for external linking.

```cmake
qe_install_targets(qe_lr_modules)

```

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

### Configure fd.x Executable

Source: https://gitlab.com/qef/q-e/-/blob/develop/PHonon/CMakeLists.txt

Sets up the fd.x executable by defining its source file and linking required libraries for phonon calculations.

```cmake
set(src_fd_x FD/fd.f90)
qe_add_executable(qe_phonon_fd_exe ${src_fd_x})
set_target_properties(qe_phonon_fd_exe PROPERTIES OUTPUT_NAME fd.x)
target_link_libraries(qe_phonon_fd_exe
    PRIVATE
        qe_pw
        qe_modules
        qe_phonon_fd
        qe_phonon_ph
        qe_fftx)
```

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

### Wannier90 Pre-processing and Interface

Source: https://gitlab.com/qef/q-e/-/blob/develop/KCW/examples/example05.1/nspin4_noSOC_MAG/1_wannier/README.md

Prepare for Wannierization by running the pre-processing step for Wannier90 and interfacing it with Quantum ESPRESSO's output.

```bash
cd occ
wannier90.x -pp wann
pw2wannier90.x -in pw2wan.p2wi | tee pw2wan.p2wo
```

```bash
cd ../emp
wannier90.x -pp wann
pw2wannier90.x -in pw2wan.p2wi | tee pw2wan.p2wo
```

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

### Compile FFTXlib Test Program

Source: https://gitlab.com/qef/q-e/-/blob/develop/FFTXlib/README.md

Compile the test program for FFTXlib by navigating to the FFTXlib directory and running 'make TEST'. This assumes QE is already configured for parallel execution.

```bash
make TEST
```

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

### Run ph.x for Phonon Calculation Workflow

Source: https://context7.com/qef/q-e/llms.txt

Executes the SCF calculation followed by the phonon calculation at the Gamma point.

```bash
# Step 1: SCF
mpirun -np 4 pw.x -i ch4_scf.in > ch4_scf.out
# Step 2: Phonons at Gamma
mpirun -np 4 ph.x -i ch4_ph.in > ch4_ph.out
# Output contains phonon frequencies in cm^-1 and THz

```