Input overview

KPP basically handles two types of input files: Kinetic description files and auxiliary files. Kinetic description files are in KPP syntax and described in the following sections. Auxiliary files are described in the section entitled Auxiliary files and the substitution preprocessor.

KPP kinetic description files specify the chemical equations, the initial values of each of the species involved, the integration parameters, and many other options. The KPP preprocessor parses the kinetic description files and generates several output files. Files that are written in KPP syntax have one of the suffixes .kpp, .spc, .eqn, or def.

The following general rules define the structure of a kinetic description file:

  • A KPP program is composed of KPP sections, KPP commands, and Inlined code. Their syntax is presented in BNF description of the KPP language.

  • Comments are either enclosed between the curly braces “{” and “}”, or written in a line starting with two slashes and a space “// “.

  • Any name given by the user to denote an atom or a species is restricted to be less than 32 character in length and can only contain letters, numbers, or the underscore character. The first character cannot be a number. All names are case insensitive.

The kinetic description files contain a detailed specification of the chemical model, information about the integration method and the desired type of results. KPP accepts only one of these files as input, but using the #INCLUDE command, code from separate files can be combined. The include files can be nested up to 10 levels. KPP will parse these files as if they were a single big file. By carefully splitting the chemical description, KPP can be configured for a broad range of users. In this way the users can have direct access to that part of the model that they are interested in, and all the other details can be hidden inside several include files. Often, the atom definitions (atoms.kpp) are included first, then species definitions (*.spc), and finally the equations of the chemical mechanism (*.eqn).