The magnon code is developed to calculate dynamic spin susceptibility based on time-dependent density functional perturbation theory. A 4 \times 4 susceptibility matrix can be calculated by solving the Sternheimer equation with corresponding perturbation of magnetic fields or electric potentials.
The code is built on top of Phonon code of Quantum Espresso (QE), partly by direcly copying/modifying subroutines from QE. A resconstruction and documentation of the code is on the way.