.\" $XConsortium: xgas.man,v 1.7 94/04/17 20:45:29 gildea Exp $
.TH XGAS 1 "Release 6" "X Version 11"
.SH NAME
xgas - animated simulation of an ideal gas
.SH SYNOPSIS
.B "xgas"
[-option ...]
.SH DESCRIPTION
.PP
\fIxgas\fP
is a physical simulation of an ideal gas in a heated box.
Gas molecules move around the box with velocities
dependent on their temperature.
A chamber consisting of two boxes contains the gas molecules;
the temperature of each box can be independently controlled
by a scrollbar.
When gas molecules collide with the walls, their temperature
approaches that of the box.
.PP
Use mouse button 1 to create molecules one at a time
at the cursor position.
Use mouse button 2 to create the maximum number of molecules
at the cursor position.
.SH OPTIONS
.TP 8
This is a toolkit program;
all the usual toolkit options are available.
.TP 8
.B \-as
Sets the autoStart resource.
.TP 8
.B \-ts
Sets the timeStepSize resource.
.TP 8
.B \-d
Sets the delay resource.
.TP 8
.B \-rb
Sets the randomBounce resource.
.TP 8
.B \-eq
Sets the equilibrium resource.
.TP 8
.B \-mm
Sets the maxMolecules resource.
.TP 8
.B \-fg
Sets the foreground.
.TP 8
.B \-bg
Sets the background.
.SH RESOURCES
The \fIxgas\fP program uses the following X resources:
.TP 8
.B autoStart
Starts the simulation automatically.  Good for canned demos.
.TP 8
.B timeStepSize
Specifies the simulated time duration in microseconds for each cycle of
computation.
.TP 8
.B delay
Specifies the real time interval between timestep computations.
.TP 8
.B randomBounce
In each wall collision, a molecule bounces elastically
(angle of incidence = angle of reflection).
A component of randomness is added to this angle.
RandomBounce varies from 0.0 (no randomness)
to 1.0 (completely random angle of incidence).
.TP 8
.B equilibrium
During each wall collision,
a molecule's kinetic energy approaches that
corresponding to the temperature of the wall.
If equilibrium is 1.0,
the molecule reaches the wall temperature immediately.
For values between 1.0 and 0.0,
the molecule approaches the temperature of the wall more slowly.
.TP 8
.B maxMolecules
Specifies the maximum number of molecules in the simulation.
.SH "SEE ALSO"
X(1), xwd(1)
.SH BUGS
.PP
When the chamber is resized,
molecules should be rearranged appropriately.
Instead,
the molecule arrays are reinitialized.
.SH AUTHOR
Larry Medwin