1. specmicp
  2. SpecMiCP



SpecMiCP / ReactMiCP


SpecMiCP is a speciation solver to find the equilibrium state of a chemical system. The system is based on a mixed complementarity formulation of the equilibrium condition for minerals.

For a mineral with volume fraction Sm, the equilibrium condition is :

Sm >= 0, -log(IAPm/K) >= 0, -Sm*log(IAPm/K) = 0

where IAPm is the ion activity product and K the equilibrium constant. This condition is reformulated using the penalized Fischer-Burmeister C-function and the system is solved using a semismooth method.

ReactMiCP is a reactive transport solver built on top of specmicp. It uses the operator splitting approach to couple transport and chemistry.


SpecMiCP is not (yet) a program but a set of libraries that can be used to solve specific problems.

The following modules are already available :

  • specmicp : core of the library, set the system, and solve it
  • reactmicp : the reactive transport solver
  • database : manage the database, parse it from a file, swap the basis, select the correct species, ...
  • micpsolver : Solve a Mixed Complementarity problem
  • odeint : integration methods for solving ordinary differential equations (for problem involving kinetics for example)
  • dfpm : a finite element module

The micpsolver and odeint modules can be use independantly.

Examples of use are provided in the examples directory.

Using SpecMiCP


To build and install SpecMiCP/ReactMiCP see the INSTALL file. To learn how to use the API the best is to look at the examples. The starting point should be the leaching in CO2-saturated examples : examples/reactmicp/saturated_react/carbonation.cpp. This file is heavily commented. Example of use of the Python interface can be found in the tests/cython directory.

Use in your own project

A cmake module can be used to find SpecMiCP in your own project. It will be installed at


The python module can be used directly if it is in your python path.


The API is documented with Doxygen and the documentation can be generated with the command :

make doc

A (maybe outdated) version of the doc can be found here.


The code is in development and the API is not considered stable yet.

Python binding

A python binding is available at the following address :



SpecMiCP is developped by F. Georget (fabieng aT princeton DoT edu). It is part of my Ph.D. work. The purpose of the PhD is to develop a reactive transport model to model the coupling between hydration, drying and carbonation in cement paste.

This Ph.D. is funded by Princeton university, Lafarge and the CSTB.

References :

  • F. Georget, J. H. Prévost, and R. J. Vanderbei. A speciation solver for cement paste modeling and the semismooth Newton method . Cement and Concrete Research, 68(0):139--147, 2015.
  • F. Georget, J. H. Prévost and B. Huet Validation of a reactive transport solver based on a semismooth speciation solver (submitted to Computational Geosciences)

A list of the references used in the code can be found in the documentation.