CalC ("Calcium Calculator") is a modeling tool for simulating intracellular calcium diffusion and buffering. CalC solves continuous reaction-diffusion PDEs describing the entry of calcium into a volume through point-like channels, and its diffusion, buffering and binding to calcium receptors. CalC is free software distributed under the terms of version 3 of the GNU General Public License.

Installation instructions:

•  CalC version 7.0 implements cooperative (2-to-1) Ca2+ buffers: version fork into 6.x & 7.x
•  CalC version x.4 implements binary file output
•  CalC version x.6 implements non-linear membrane pump
•  CalC version x.7 implements spherical enclosures and obstacles
•  CalC version x.7.2 implements space-dependent calcium uptake
•  CalC version x.8 implements arbitrary volume shapes and 2D surface plots
•  CalC version x.9.1 important bug fix! (thanks to Christian Stricker!)
•  CalC version x.9.7 allows to target membrane buffers to specific volume(s) or obstacles(s)
•  CalC version x.10.1 allow cross-platform plots using freeglut OpenGL library.
•  CalC version x.10.7 allows 2nd surface Ca2+ flux to implement both NCX & PMCA Ca2+ extrusion.
CalC versions 6.x.x mirror versions 7.x.x, but allow simple (one binding site) Ca2+ buffers only, and therefore run faster; use them whenever cooperative buffers with two binding sites are not needed

NEW: CalC versions x.10.1 and higher allow direct window plots using cross-platform freeglut OpenGL library.
If using Windows OS, place the freeglut.dll dynamic library in the same folder with the executable provided below.
VersionCa2+ buffer type Source (all platforms) Stand-alone executables
7.10.8 Jun 25, 2024 Two Ca2+-binding sites Zip | Tar | GitHub Win_64 macOS M1 macOS x86
6.10.7 Apr 5, 2023 One Ca2+-binding site Zip | Tar | GitHub Win_64 macOS M1 macOS x86
[ Link to full descriptions of all CalC release updates ]

CalC Description and Features:

CalC uses a variation of the Alternating Direction Implicit (ADI) finite difference method, which is very CPU-time efficient, and accurate to 2nd order in time and space. Time-step is varied adaptively during the simulation.
CalC is provided on an as-is basis, but I will respond to any bug reports or technical questions, as soon as I can. If you use CalC in your published work, please cite our 2002 Biophys J article, and please send me a reference for inclusion in the CalC publication list upon publication.

CalC is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the license, or (at your option) any later version. CalC is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the license file for more details.

Supported in part by the National Science Foundation grants 0417416, 0817703 and 1517085. However, NSF bears no responsibility for any findings, recommendations or conclusions provided by this material.
Last modified: Jun 25, 2024             Maintained by Victor Matveev