Puppy Linux Discussion Forum

[tombh]

Here is a particle simulator called Pixies I have been making.

I had the original idea some 12 years ago when I was 14 and started it in Quick Basic. Then when I started using Puppy, C seemed so much more accessible so I rewrote Pixies in C for the increased speed. It uses an equation called the Lennard-Jones Potential (see images) to derive the forces between particles given their distances form each other.

The project is not finished, there are some functions that don't work and an energy leak bug.

Particles are added by clicking in the black box with the left mouse button. Particles and settings can be added/adjusted in real time. Solids, liquids and gasses can all be simulated with the right settings.

The Control Centre is made up of two areas -- Environment settings and Individual Particle settings. The latter is a little more complicated in that it has two modes -- Creation mode and Selector mode. Creation mode causes mouse clicks to add particles and Selector mode causes mouse clicks to select the nearest particle for adjustment.

Static particles and thus static 'containers' can be made by creating/selecting particles with the 'static radio toggle'.

I haven't had the time to do anything with it for ages, but I put it up here in case anybody finds it fun or useful.

Enjoy

[Lobster]

thank for releasing this
might be required for DIDO (the final part of the Tmxxine project)
http://tmxxine.com/wik/wikka.php?wakka=DIDOhardwareProject

[Sage]

We used to listen to all this kind of simulation thing back in the Sixties & Seventies when John Enderby was still prof in Physics down at Bristol.
All very pretty, but.....
Simulations depend upon selecting 'realistic' input parameters, in this case pair potentials. Ultimately, these rely for their integrity upon experimental data. In other words, the whole rapidly descends into an exercise in circular logic. Put in realistic data - you get out plausible answers. Bigger and better computers don't help. More efficient code doesn't help. Even 'improved' modelling doesn't help, because, as Stephen Hawking readily admits, ultimately all models derive from the intangible intuition of the human consciousness. Fallible and limited, indeed! It is now considered that because human experience will never be capable of phenomenalising dimensions beyond the third, a complete comprehension of the space-time continuum can never be achieved.
But don't let all that put you off having fun and spending the departmental budget!

[Lobster]

[Sage]

[Sage]

PS. Those leakages. They never go away. Your model must, by definition, refer to an empirical unbounded infinite ensemble of particles. In a real simulation, your computer, however large, will always be bounded and exhibit edge effects. It is not sufficient for particles leaving the box to be accounted for by re-entry at the opposite edge.
Your calculation will also be bounded in time. It isn't permissible to allow it to 'stop' or even 'start' because this imposes unrealistic offsets, which, however small, are finite and aggregate through massive iteration.
It is also difficult to the point of impossibility to represent the entire spectrum of allowable properties (usually temperature - Boltzmann distributions) for individual particles. Goodness knows what 'corrections' are needed for 'uncertainty', 'duality' and all those more esoteric factors!

[Flash]

Don't forget to include acceleration, e.g. due to gravity. I'm not kidding. It would be useful for examining how mixed gases act in the atmosphere.

[tombh]

Of course this is simulation of physical reality on, what is now considered, a relatively macroscopic scale! Nevertheless I must admit that the inspiration behind it is no less than a desire to get closer to the inner most workings of existence If one could somehow recreate reality with the simplicity of one equation then all one would need do is, understand that equation, and the universe would be your oyster. If only!

Yeah, those leakages can never be plugged, no matter how accurate one is, the exponential proliferation of even the smallest discrepancies will always multiply into tangible deviations. Though, one must of course be careful not to throw the baby out with the bath water -- a distorted representation is fundamentally different to outright fabrication. There certainly are implicit shortcomings with conceptualisation, thought and theory but that cannot then also mean that they are utterly redundant. I worry when the question of reality no longer excites me, to be perpetually struck by that which is unprecedented is perfectly within my grasp. So often I just want to retire to the conclusion that it's all too complicated and must therefore be inexplicable -- but isn't that just another subtle and unjustifiable explanation?

I'm sometimes saddened that I won't get to see a lot of the future! So much to see, sure, ways of life far beyond our current frame of reference. My comfort though is that newness is always newness, it's always something that has no frame of reference. And that's nothing new! It's always been and always will be like that!

Happy Days

PS. There's a gravity slider already in there -- which of course accelerates all particles equally regardless of their mass

[Sage]

[tombh]

Wave theory simulator! Goodness I might apply for funding, mind you whilst I'm at it I might as well go the whole hog and propose support for infinite dimensions and string theory. Well I suppose that's what a theory is, a set of rules that can be applied to simulate reality. Does string theory explain the random popping into existence of fundamental particles? Mind you can anything ever explain how the big bang happened in the first place? That was a rather significant popping into existence I must say!

Is g like a local gravitational constant and G a universal one or something? My simulator doesn't account for an expanding universe at the moment but you can change the colours of the particles if that's any consolation!