Ps-i version 2.4 manual
About Ps-i 2.4.
Ps-i 2.2 is an environment for study of agent-based simulations.
The design of Ps-i 2.0 had the following goals in mind:
- the model implemented in the program should be changeable by end users
- 99% of the program's codebase should be shared between Windows and Linux (Unix) versions
- full functionality of the program should be available under Linux to facilitate fast development
- the featureset of the program should encompass the featureset of the first version.
To achieve these goals the following design decisions were made:
- the model description is external to the program and is contained in model configuration file
(usually with extension ".mdl")
- the user interface was implemented using Tcl/Tk library which allowed all of the code (except for two startup files) to
be shared between Linux (Unix) and Windows versions
- the core of the model consists of the library of functions and the data related to the model being
currently run; the dependencies between library functions are weak - that is they are due to the particular
form of the data structures and not the algorithms implemented in the model.
Version 2.2 builds upon its precursor with several improvements:
- simplified model specification file syntax
- improved user interface
- ability to specify a number of parameters, easily changeable from
- faster runs with routine optimization, speculative evaluation and
- faster field display
- the ability to save and restore program runs
- the ability to import landscape files from Ps-i 1.0 and 1.5
- the ability to run Tcl/Tk scripts
The following improvements were incorporated in 2.4.0:
- selection tool allows to select areas using geometrical figures and
- effect tool allows to change attributes of agents in the area created by
selection tool according to user-defined expressions
- improved interactivity
- support for tcl scripts embedded in model specification files
- hash functions that can be used to generate repeatable random sequences
- templatized creation of new model specification files (ABIR model,
- dynamic addition of attributes
Ps-i 2.4 model configuration file.
The model file consists of the following sections:
Model configuration files are commonly stored with extension .mdl.
It is generally recommended that a novice user takes an existing configuration file and use it as a template
for constructing description of his/her model.
Note that the snapshot files (with extension .snp) have identical syntax,
but are not meant to be edited by the end user.
Ps-i 2.4 scripting interface
Ps-i 2.4 has the ability to load Tcl/Tk scripts and execute scripts embedded in model
specification files and snapshots. These files are commonly stored
with extension .scp. All standard Tcl/Tk commands are available to the user.
In addition, there are a number of commands specific to Ps-i 2.4: