APBS (Adaptive Poisson-Boltzmann Solver) is a software package for the numerical solution of the Poisson-Boltzmann equation (PBE), one of the most popular continuum models for describing electrostatic interactions between molecular solutes in salty, aqueous media. APBS was designed to efficiently evaluate electrostatic properties for a wide range of length scales to enable the investigation of molecules with tens to millions of atoms.
The iAPBS package provides a C/C++ and Fortran interface to the APBS library through a single function call. The interface code can be compiled as a library (libiapbs.a) which can be linked with a Fortran or C/C++ application thus making most of APBS functionality available from within any C/C++/Fortran code.