GENAPAC - A genetic algorithm for parameter calibration

The GENAPAC computer code is a genetic algorithm for parameter calibration. The code is written in FORTRAN 95. This user’s manual describes the source code and provides information to facilitate its use. This document contains an introduction (Chapter 1) which gives an overview of the general functioning of genetic algorithms. Chapter 2 provides explanations about the main program and the subroutines, whereas the Chapter 3 provides the source code. Two examples are given to demonstrate the versatility of the code in determining parameter estimates for complex problems (Chapter 4). The GENAPAC code can be coupled with any computer code such as those that solve the water flow and contaminant transport equations in soils and aquifers. For both of the two examples the HYDRUS-1D code (Šimůnek et al., 2009) for variably saturated water flow was used.