How to generate a JPEG file from the Lorenz program

What is a CGI program?

A CGI program is an executable (a real executable - not a HTML page) that runs on a WEB server (Apache 2 or similar) normally reacting on HTML forms or simple links and generating an answer page that the user sees as a reaction on clicking on a link.

Be warned: this is not a simple procedure. We do not consider here the build process for the various programs (the source contains hints for building the executables). We neither explain how a typical WEB server handles CGI requests.

Steps executed by the CGI program

The steps executed in the following text will be executed automatically in the background - no need for you to execute them manually. But if you need similar procedure then this might be helpful. BTW: If you execute program Lorenz1EH.f90 directly on you laptop then the procedure to generate a JPEG diagram is much simpler (but similar).


You find all source code (FORTAN, C++, C, shell script, gnuplot macro) in this ZIP file.


The following diagram shows the steps executed in a CGI program after having clicked on the "start calculation" button in the parameter form.