PSF

PSF is an acronym that can refer to several different concepts depending on the context. Among its most common meanings are the Python Software Foundation, the point spread function in optics and imaging, and the Protein Structure File used in molecular dynamics software.

The Python Software Foundation is a nonprofit organization dedicated to advancing and sustaining the Python programming language. It coordinates development and governance, hosts conferences such as PyCon, supports educational initiatives, and maintains licensing infrastructure, including the Python Software Foundation License (PSFL), which applies to Python's distribution and related works.

In optics and imaging, the point spread function describes how an imaging system responds to a distant or infinitesimal point of light. The PSF characterizes the distribution of light in the image plane and directly affects resolution and deconvolution outcomes. Atmospheric turbulence, aberrations, and sampling influence the PSF, and accurate PSF models are essential in astronomy and microscopy.

In computational chemistry and biophysics, a Protein Structure File is a topology file that defines atoms, residues, bonds, angles, and dihedrals for a molecular system. The PSF is used together with coordinate and parameter files by software such as CHARMM, NAMD, and VMD to simulate molecular dynamics and analyze structural properties.