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#+AUTHOR: Dr. John A.R. Williams #+EMAIL: J.A.R.Williams@aston..ac.uk #+LINK: hs http://www.lispworks.com/reference/HyperSpec//%s #+STARTUP: showall * Summary Lisp Educational Network Simulator (LENS) is a discrete event simulation framework written in Common Lisp. It provides a generic architecture for modelling in problem domains where the system may be represented by the exchanging of messages between entities. It is being used to develop simulations for research into Wireless Sensor Networks. ** Why Use LENS? LENS is easier to extend and develop for than other network simulators. The decision to write a new network simulator in |LISP| was based upon a number of observations: - Simulation environments require a core model and a means for specifying particular simulations at run time. Most simulators have the core model written in a compiled language (e.g. C++) for efficiency and have a separate embedded run time interpreter (e.g. Tcl or a domain specific language) for describing the particular simulation. |LISP| provides the full language and compiler environment at run-time so there is no need for this separation. - Users of a simulator will want to describe their problem in a way which matches their particular domain. |LISP| is an extensible language which is especially good for writing domain specific languages. - LISP enables introspection of all aspects of the simulated system while it is running without any additional programming. Most other simulators provide only limited introspection capabilities which have to be explicitly programmed in. - In modern LENS the simulations are run in a separate thread to the normal Common Lisp read-eval loop so the user can probe or modify the simulation even while it is running. The architecture of LENS is inspired by the [[http://www.omnetpp.org/ [OMNET++]] simulator framework written in C++ however may aspects of that design become simpler when implemented in LISP. ** Dependences LENS has been developed using the SBCL <http://sbcl.sourceforge.net/> Common Lisp implementation. Implementation specific features are accessed through a thin compatibility layer in `core/compatibility.lisp` which is the only file that should need changed to port it to other implementations. Currently the only implementation feature used is threading so porting is a minimal task. If you do port LENS to another implementation please send me the changes to encorporate back into the main distribution. LENS is dependant on the following additional Common Lisp libraries - asdf: http://www.cliki.net/asdf - Closer-MOP: http://common-lisp.net/project/closer/ - split-sequence: http://www.cliki.net/SPLIT-SEQUENCE - trivial-gray-streams: http://www.cliki.net/trivial-gray-streams - data-format-validation : http://www.cliki.net/CL-DATA-FORMAT-VALIDATION - clrs : https://github.com/willijar/clrs ** Installation LENS is available from the GIT repository. You can clone and install LENS like this: : cd ~/src/ : git clone https://github.com/willijar/LENS.git ** How to Use 1. The file =lens.asd= provides the asdf system definition for LENS. You should place a symbolic link to this file in a system definition directory where ASDF can find it. Similarly for 2. Load LENS with #+BEGIN_SRC lisp (asdf:operate 'asdf:load-op :lens) #+END_SRC 3. Load the simulation system you want with #+BEGIN_SRC lisp (asdf:operate 'asdf:load-op :simulation-system-name) #+END_SRC e.g. =(asdf:operate 'asdf:load-op :lens.samples)= for the provided example `samples` network. 4. Make the simulation package your current package #+BEGIN_SRC lisp (asdf:operate 'asdf:load-op :simulation-package-name) #+END_SRC e.g. =(in-package :lens.samples)= for the provided example networks. 5. Load and run a simulation configuration from a configuration file #+BEGIN_SRC lisp (run-simulations "configuration-file.ini" :config "section-name") #+END_SRC e.g. =(run-simulations +tictoc+ :config "TicToc2")= will run the sample simulation specified by section "TicToc2" in the samples configuration file (=+tictoc+= is defined in the =:lens.samples= package to point to this file) ** Feedback If you have have questions, remarks, or ideas about LENS or want to submit a bug report then please email me at <mailto:J.A.R.Williams@aston.ac.uk>