Simulating a simple analog computer?

[maly]

Hi, anyone into analog computing? I was wondering if there is an example of a simple virtual analog computer somewhere (open source), I can't seem to find one. I'm interested in basic principles of advancing the state of the network, as you must do on a digital computer. I found some complex simulators (SPICE and variants), but that seems like an overkill for my needs - just basic ideal adders, multipliers, integrators, delays and maybe a few others.

 

[Tom.G]

Here are a few links for some ideas. The edn.com article has a download using LTSPICE and ijee.ie has a suggestion to use a spreadsheet.
These, and many more, were found doing a Google searches for:
analog computer simulation
virtual analog computer

http://www.edn.com/design/analog/4376400/A-virtual-analog-computer-for-your-desktop

http://www.ijee.ie/articles/Vol18-6/IJEE1324.pdf

Also MATLAB has SIMULINK which is an analog computer simulation.

 

[maly]

Thanks, Tom, the spreadsheat computer looks useful because they show a bit of code. I'm specifically interested in how these simulators work internally (that is why the preference for open source). On a mechanical or electronic analog computer, all processes happen simultaneously, but then on a digital computer we have to simulate this by having state A, and then advancing to a state B by applying a small timestep, and it seems to matter if we go around the network advancing the state of every element in sequence, or if we store the complete state and then advance every element given only the previous states. I'm a bit confused how this works, and how well it scales to larger networks.