The software package CODICA is a tool for the data analysis of acquisition or demagnetisation curves of remanent magnetisation, developed by Ramon Egli. It consists of the package CODICA (COercivity DIstribution CAlculator) and the package GECA (GEneralised Coercivity Analyser).

What does CODICA do?
CODICA eliminates efficiently measurement noise from acquisition or demagnetisation curves of remanent magnetisation (based on rescaling procedures) and calculates then the derivative (also called coercivity distribution or coercivity spectrum).
GECA models the previously calculated coercivity distribution with a linear combination of special generalised functions. A Pearson's X ² goodness of fit test evaluates the number of functions required for the best-fit and an error estimation allows to calculate the confidence limit for each model parameter.

Requirements
Both progammes are written in Mathematica, a programming language similar to other traditional computer languages such as C, Pascal or FORTRAN. The usage of CODICA implies that Mathematica is installed on your computer. CODICA has been developed for Mathematica under Windows, but with small code modifications it is also compatible with Mathematica for Linux/Unix.  Two releases are available, currently, operating with two different versions of Mathematica. Release 1 for Mathematica under Linux/Unix is available, too.

Installation
1. Install Mathematica on your computer.
2. Download the zip-file from below and unpack it.
3. Open the file install.txt, which is located in the folder Install, read it and follow the instructions.

Download
Both releases can be downloaded following the links below.

Release 1 (2002) Mathematica v.3.0 or later for Windows must be installed in your computer.
The zip file contains: installation instructions (in file install.txt), CODICA 2.3  and GECA 1.1 (both in file Codica.m), manuals (pdf-format) and examples.

r1.zip (3.2 Mb)

Release 1L (2003) Mathematica v.3.0 or later for Linux/Unix must be installed in your computer.
The tar.gz file contains: installation instructions (in file install.txt), CODICA 2.3  and GECA 1.1 (both in file Codica.m), manuals (pdf-format) and examples.

r1L.tar.gz (3.2 Mb)

Release 2 (2004) Mathematica v.5.0 for Windows must be installed in your computer.
The zip file contains: installation instructions (in file install.txt), CODICA 3.0 and GECA 2.0 (both in file Codica.m), manuals (pdf-format) and examples.

  r2.zip (3.3 Mb)

Manuals only
Here you can download the reference manuals of both programmes in pdf-format:

  CODICA 3.0 (2004) (1.5 Mb)
  GECA 2.0 (2004)   (1.7 Mb)

Notice
Both programmes are still at the stage of development. Any kind of suggestions are welcome. Do not hesitate to contact the author by e-mail: eglix007@umn.edu.

References
CODICA
R. Egli, Analysis of the field dependence of remanent  magnetization  curves, Journal  of Geophysical   Research,   108   (B2),   2081,   doi 10.1029/2002JB002023, 2003.

GECA
R. Egli, Analysis of the field dependence of remanent  magnetization  curves, Journal  of Geophysical   Research,   108   (B2),   2081,   doi 10.1029/2002JB002023, 2003.

Heslop, D.,  Dekkers, M.J., Kruiver, P.P. and  I. H. M. van Oorschot, Analysis of isothermal remanent magnetization acquisition curves using the expectation-maximization algorithm, Geophysical Journal International,148, 58-64, 2002.

Kruiver P.P.,  Dekkers M.J. and D. Heslop, Quantification of magnetic coercivity components by the analysis of acquisition curves of isothermal remanent magnetisation, Earth and Planetary Science Letters, 189, 269-276, 2001.