home *** CD-ROM | disk | FTP | other *** search
Information Presentation Facility markup | 1993-12-12 | 23.1 KB | 634 lines |
- .* Help file for PMChaos. (C) Copyright Matthew Austern, 1993.
- .*
- .* Permission granted to use, distribute, and modify, provided that this
- .* notice remains intact. If you distribute a modified version, you must
- .* identify your modifications as such.
- .*
- .*
- :userdoc.
- .***************************************************
- .* This is the introductory panel.
- .***************************************************
- :h1 res=1. PM Chaos: Extended Help
- .*
- :p.
- :i1 id=calc.calculation
- :hp4.PM Chaos:ehp4. is a simulation of a simple chaotic system: the
- :hp4.standard mapping:ehp4.. This is a simple function that takes a
- point (J,theta) into another point (J',theta'). If you keep applying
- this function again and again, you get a sequence of points. For certain
- initial conditions this sequence is a smooth trajectory, and for other
- initial conditions it is chaotic.
- :p.
- To start a calculation, click the left mouse button anywhere within the
- box of the graph. PM Chaos will begin calculating the sequence of
- points starting with the initial point you have chosen. The calculation
- continues until you stop it, either by clicking the left mouse button
- somewhere else (this will stop the first calculation and start a new
- one), by selecting :hp2.Stop!:ehp2. from the :hp2.Control:ehp2. menu,
- or by clearing the screen.
- :p.:hp4.Related information: :ehp4.
- :ul.
- :li.:link reftype=hd res=100. The standard mapping :elink.
- :li.:link reftype=hd res=200. Using the program :elink.
- :eul.
- .***************************************************
- .* Here is the section that describes the physics.
- .***************************************************
- :h1 res=100. Physics of the standard mapping
- :i1. phase space
- :i1. trajectory
- :i1. Hamiltonian
- :i1 id=Map.mapping
- :i2 refid=Map.area-preserving
- :p.
- The standard mapping is a simplified set of equations that has many of the
- same qualitative topological properties as do actual physical systems
- in classical mechanics.
- :p.
- The evolution of a classical mechanical system is given by a set of
- differential equations determined by the Hamiltonian.
- It is numerically easier, however, to work with a difference equation,
- that is, one that doesn't evolve continuously, but where, given
- a point, there is a function that just gives you the next point in
- the sequence.
- :p.
- If you don't know much classical mechanics, you may want to skip the
- next three paragraphs. You don't need to understand them in order to
- use the program.
- :p.
- Consider a time-independent Hamiltonian with two degrees of freedom,
- i.e., two canonical coordinates and two canonical momenta. The state
- of the system is represented by a point in the four-dimensional
- :hp4.phase space:ehp4., and the time evolution of the system from some
- initial state is a trajectory in phase space. We can choose some
- arbitrary two-dimensional surface in this phase space, a
- :hp4.surface of section:ehp4., and study the successive intersections of a
- trajectory with that surface. This gives us a set of difference
- equations on a two-dimensional reduced phase space.
- :p.
- A time-independent Hamiltonian leads to a conserved energy; this means
- that a trajectory must lie in some three-dimensional subspace of the
- original four-dimensional phase space. It also means that the
- mapping given by the surface of section (a canonical transformation)
- is area-preserving, that is, that any region of the two-dimensional
- reduced phase space gets mapped to a region of equal area. If the
- Hamiltonian is :hp4.integrable:ehp4.
- (i.e., if there exists a constant of the motion other than the total
- energy), then motion is actually in a two-dimensional subspace of
- phase space. In that case, the successive points in the surface of
- section lie on closed curves in the reduced phase space.
- :p.
- This is most easily seen in angle-action variables. In that case, the
- mapping equation for an integrable system is
- :font facename=Courier.
- :lines align=left.
- J' = J
- theta' = theta + f J.
- :elines.
- :font facename=default.
- The standard mapping is very similar to this: it is a near-integrable
- area-preserving mapping in angle-action coordinates.
- .*
- .* End of this panel. Now some links...
- .*
- :ul.
- :li.:link reftype=hd res=101. Equations of the standard mapping :elink.
- :li.:link reftype=hd res=104. Where to learn more :elink.
- :eul.
- .***************************************************
- .* Here is the panel with the actual equations.
- .***************************************************
- :h1 res=101. The standard mapping
- :i1. J
- :i1. theta
- :i1 id=K.K
- :i2 refid=K.defining equation of
- :i2 refid=Map.standard
- :i2 refid=calc.equations of
- :p.
- The standard mapping is given by the equations
- :font facename=Courier.
- :lines align=left.
- J' = J + K sin(theta)
- theta' = theta + J', mod(2 pi).
- :elines.
- :font facename=default.
- :p.
- It is defined for J and theta in the range (0, 2 pi).
- :ul.
- :li.:link reftype=hd res=102. Significance of K :elink.
- :eul.
- .***************************************************
- .* This panel defines what K means.
- .***************************************************
- :h1 res=102. The K factor
- :i2 refid=K.significance of
- :i1. stochasticity
- :i1. fixed points
- :i1. separatrices
- :p.
- K is the stochasticity parameter. For K=0, the standard mapping is
- integrable, and the action variable, J, is a constant of the motion.
- For K>0 there are some regions of stochasticity, but they are isolated
- when K is small, and J is nearly constant for many trajectories. For
- any K<1 there are separatrices dividing the screen into at least two
- regions. That is: if the motion begins near J=0, it will never end up
- near J=2 pi.
- :p.
- Motion becomes globally stochastic at
- :link refid=transition reftype=fn.K=1:elink..
- At this point, the last separatrix disappears,
- and there is nothing separating the J<pi and J>pi regions.
- :fn id=transition.
- Actually, the transition isn't exactly at K=1. The approximate value is
- K=0.9716. See
- A.J. Lichtenberg and M.A. Lieberman,
- :hp1. Regular and Stochastic Motion, :ehp1.
- for more details.
- :efn.
- .*
- .*
- :p.
- For any value of K there are still some :hp4.islets of stability:ehp4.,
- but they become more and more isolated, and motion becomes more and
- more chaotic, as K increases. Note that there are always at least two
- fixed points: (J,theta) = (0,pi), and (J,theta) = (2pi,pi). For
- K<4, these fixed points are stable.
- :p.
- This program limits K to the range 0<K<3, because motion with larger
- values of K is too disordered to be very interesting.
- .*
- .* End of the K panel. Now some links.
- .*
- :p.
- :hp4.Related information: :ehp4.
- :ul.
- :li.:link reftype=hd res=220. Setting K :elink.
- :li.:link reftype=hd res=101. Equations of the standard mapping :elink.
- :li.:link reftype=hd res=100. Discussion of the physics :elink.
- :eul.
- .***************************************************
- .* Here is the panel with the bibliography.
- .***************************************************
- :h1 res=104. References
- :i1. references
- :i1. Lichtenberg, A. J.
- :i1. Lieberman, M. A.
- :i1. Goldstein, H.
- :p.
- The standard mapping is Equation 4.1.3 of
- :lm margin=8.
- :rm margin=7.
- :font facename='Tms Rmn'.
- :p.
- A. J. Lichtenberg and M. A. Lieberman,
- :hp1. Regular and Stochastic Motion, :ehp1.
- New York: Springer-Verlag, 1983.
- :lm margin=1.
- :rm margin=1.
- :font facename=default.
- :p.
- Section 4.1b describes the standard mapping in detail; chapter 3 discusses
- mappings in general. This book is somewhat advanced, and assumes that you
- already know about Hamiltonian dynamics, angle-action variables, and
- so on. If you don't, the standard reference is
- :lm margin=8.
- :rm margin=7.
- :font facename='Tms Rmn'.
- :p.
- H. Goldstein,
- :hp1. Classical Mechanics (second edition), :ehp1.
- Reading: Addison-Wesley, 1980.
- :lm margin=1.
- :rm margin=1.
- :font facename=default.
- :p.
- .*************************************************************
- .*************************************************************
- .** And here is the actual program documentation. **
- .*************************************************************
- .*************************************************************
- :h1 res=200. Using PM Chaos
- :i2 refid=calc.starting a
- :i1. changing window size
- :p.
- At the most basic level, using PM Chaos is very simple. Just click
- the left mouse button anywhere within the graph on the main screen.
- PM Chaos will use the point you have selected as the initial conditions
- for a calculation. It will then begin calculating a sequence of points
- and displaying them on the screen; each point is determined from the last
- by a simple :link reftype=hd res=101.equation:elink..
- If you click the left mouse button in the graph while a calculation is
- in progress, it will stop the old calculation and start a new one.
- :p.
- The :hp2.Control:ehp2. menu contains
- a command to stop a calculation that is in progress, a
- command to clear the screen (if there is a calculation in progress,
- clearing the screen will stop it), and a command to quit the program.
- You can also quit the program by selecting :hp2.Close:ehp2.
- from the system menu.
- :p.
- Normally, the points get displayed very quickly. In
- :link reftype=hd res=240. slow motion mode:elink., however,
- the points are display slowly enough so that you can see the
- progress of the calculation explicitly.
- :p.
- You can resize PM Chaos's window in any of the normal ways that
- you can resize any
- Presentation Manager:link refid=TM reftype=fn.**:elink. window:
- either by using the sizing border, or by using the minimize
- and maximize buttons at the upper right-hand corner of the window,
- or by selecting :hp2.Size:ehp2. from the system menu.
- .*
- :fn id=TM.
- Presentation Manager is a trademark of the IBM Corporation.
- :efn.
- .*
- :p.
- That's really all you need to know to use PM Chaos. There are a number
- of additional options that you can select, though.
- :ul.
- :li.:link reftype=hd res=210. Choosing the color :elink.
- :li.:link reftype=hd res=220. Setting K :elink.
- :li.:link reftype=hd res=230. Changing the range of the graph :elink.
- :eul.
- .*
- .*
- .***************************************************
- .* Here's the panel on using the color dialog.
- .***************************************************
- :h1 res=210. Choosing the color
- :i1. color
- :p.
- You can change the color that PM Chaos will use to display results. You
- can mix different colors on the same plot; that is, you can display the
- results of a calculation in one color, and the results of the next
- calculation in a different color. This is a convenient way to distinguish
- trajectories that lie close to each other.
- :p.
- You choose the color by using the color dialog, which you get to by selecting
- :hp2.Colors:ehp2. from the :hp2.Options:ehp2. menu.
- :p.
- The color dialog displays sixteen different colors, each of which has
- a button next to it. Click on the color that you would like to use
- for the next calculation.
- :p.
- When you click on the :hp2.OK:ehp2. button, the color for the next
- calculation will be changed. If there is already a calculation in
- progress, it will stop. If you click on the :hp2.Cancel:ehp2.
- button, then the current color will not be changed, and the
- calculation in progress (if any) won't be stopped.
- .*
- .*
- .***************************************************
- .* Here's the help panel for the K factor dialog.
- .***************************************************
- :h1 res=220. Setting K
- :i2 refid=K.setting
- :p.
- The :link reftype=hd res=101.equation:elink. for the standard mapping
- depends on the :link reftype=hd res=102.K:elink. factor,
- which deterines the degree of stochasticity. Essentially, the
- larger K is, the more chaotic is the behavior of the system.
- If K=0, the system is completely regular. If K is much larger than 1,
- the system is so chaotic that it is no longer very interesting.
- :p.
- You can change the value of K by using the K factor dialog, which you
- get to by selecting :hp2.Set K:ehp2. from the :hp2.Options:ehp2. menu.
- :p.
- This dialog box uses a slider. You can change the value of K by dragging
- the slider arm; you can also use the buttons to the left of the slider,
- or you can use the arrow keys on the keyboard. The value you have selected
- is displayed just above the slider control.
- :p.
- When you click on the :hp2.OK:ehp2. button, the value of K will be
- changed, and the screen will be cleared. If you click on the
- :hp2.Cancel:ehp2. button, then the current value of K will remain
- unchanged, and the calculation in progress (if any) won't be stopped.
- .*
- .*
- .***************************************************
- .* Here's the general panel for setting the range.
- .***************************************************
- :h1 res=230. Setting the range
- :i1 id=range.range
- :i1 id=zoom.zooming
- :p.
- You can change the range of the graph, so that you can look more closely
- at some particular part of it. There are three ways to change the range.
- No matter which method you use, however, changing the range will stop
- any calculation that may be in progress, and will clear the screen.
- :ul.
- :li.:link reftype=hd res=231. Zooming out :elink.
- :li.:link reftype=hd res=232. Zooming in :elink.
- :li.:link reftype=hd res=233. Using the range dialog :elink.
- :eul.
- .*
- .***************************************************
- .* Using the zoom out option.
- .***************************************************
- :h1 res=231. Zooming out
- :i2 refid=range.zooming out
- :i2 refid=zoom.out
- :p.
- If you select :hp2.Zoom Out:ehp2. from the :hp2.Range:ehp2.
- menu, then the graph will be set to the maximum possible range: both
- axes will go from 0 to 2 pi.
- :p.
- Doing this will clear the screen; if there is a calculation in progress,
- it will be stopped.
- .*
- .***************************************************
- .* Using the zoom out option.
- .***************************************************
- :h1 res=232. Zooming in
- :i2 refid=range.zooming in
- :i1. zoom rectangle
- :i2 refid=zoom.in
- :p.
- To zoom in to a particular region of the graph, you must first define a
- :hp2.zoom rectangle:ehp2.. You do this with the right mouse button.
- :p.
- Move the mouse pointer to somewhere within the graph, and then move
- the mouse while holding down the right mouse button. You will see a
- rectangle on the screen: one corner of it will be at the point where you
- first began to hold down the right mouse button, and the other will be
- at the current posigion of the mouse. The rectangle will continue to
- move around as long as you're holding down the right mouse button.
- :p.
- When you release the right mouse button, the zoom rectangle will
- remain in position. If you select :hp2.Zoom In:ehp2. from the
- :hp2.Range:ehp2. menu, then the range of the graph will be set to
- be the region outlined by the zoom rectangle. Doing this will clear
- the screen; if there is a calculation in progress, it will be stopped.
- :p.
- The zoom rectangle will be cleared if you start a calculation, if you
- clear the screen, or if you press the right mouse button to define a
- different zoom rectangle.
- .*
- .***************************************************
- .*
- :h1 res=233. Using the range dialog
- :i2 refid=range.dialog box
- :p.
- The simplest way to set the range is usually with the :link reftype=hd
- res=231.Zoom Out:elink. or the :link reftype=hd res=232.Zoom In:elink.
- options. If you want to type the ranges in explicitly,
- though, the range dialog allows you to do that. You get to the range
- dialog by selecting :hp2.Set Ranges:ehp2. from the :hp2.Range:ehp2.
- menu.
- :p.
- The range dialog has four entry fields: the minimum and maximum values
- of the range for each of the two coordinate axes. You can type in a
- number in each of those entry fields.
- :p.
- For each axis, the minimum value must be at least 0 and the maximum must
- be no greater than 2pi. Also, of course, the maximum must be
- greater than the minimum...
- :p.
- When you click on the :hp2.OK:ehp2. button, the range will be
- changed to the value you have typed in, and the screen will be
- cleared. If you click on the :hp2.Cancel:ehp2. button, then the
- range will remain unchanged, and the calculation in progress (if any)
- won't be stopped.
- .*
- .* The next two panels deal with slow motion mode.
- .*
- :h1 res=240. Slow motion mode
- :i1 id=Slow.Slow motion mode
- :p.
- In slow motion mode, a calculation is done slowly enough so that you
- can see the points calculated one at a time. This lets you see,
- explicitly, how the mapping function takes one point into another.
- :p.
- When a calculation is in progress in slow motion mode, the current point
- is displayed prominently in the graph window, and its coordinates are
- displayed in a separate window.
- :p.
- You can :link reftype=hd res=241.set the speed:elink. of
- slow motion mode by selecting the
- :hp2.Delay Time:ehp2. item from the Options menu.
- :p.
- You can turn slow motion mode on or off by selecting the
- :hp2.Slow Motion:ehp2. item from the Options menu. If a calculation
- is in progress when you turn slow motion mode on or off, it will
- be stopped.
- .*
- .*
- :h1 res=241. Setting the slow motion speed
- :i2 refid=Slow.Setting speed
- :p.
- In slow motion mode, PM Chaos pauses for a specified length of time
- after displaying each new point. Selecting the
- :hp2.Delay Time:ehp2. item from the Options menu will display
- a dialog box that allows you to set that length of time.
- This delay time has no effect unless you are in slow motion mode.
- :p.
- The delay time is specified in units of 1/10 seconds. So, for example,
- if you want a delay of 1 second, you type in a delay time of 10.
- The delay time must be a non-negative integer. You may specify a delay
- time of 0, but doing that isn't very useful.
- :p.
- When you click on the :hp2.OK:ehp2. button, the delay time will be
- changed. If there is a calculation in progress, and if it is using
- slow motion mode, it will be stopped. If you click on the
- :hp2.Cancel:ehp2. button, then the delay time will remain unchanged.
- .*
- .*************************************************************
- .*************************************************************
- .** That's pretty much it. What remains is a bit of fluff: **
- .** key assignments, brief descriptions of menu items, and **
- .** so on. **
- .*************************************************************
- .*************************************************************
- :h1 res=300. The Control menu
- :p.
- The :hp2.Control:ehp2. menu contains the following options:
- :ul.
- :li.:link reftype=hd res=301. Stop! :elink.
- :li.:link reftype=hd res=302. Clear Screen :elink.
- :li.:link reftype=hd res=303. Exit :elink.
- :eul.
- .***********
- :h1 res=301. Stop!
- :i2 refid=calc.stopping a
- :p.
- This menu option stops the calculation that is in progress. If there isn't
- any calculation in progress, this option is disabled.
- :p.
- Another way to stop a calculation in progress, without using the menu,
- is to click the mouse somewhere :hp1.outside:ehp1. the borders of the graph.
- .***********
- :h1 res=302. Clear Screen
- :p.
- This option clears the screen. If a calculation is in progress, it is
- stopped.
- .***********
- :h1 res=303. Exit
- :p.
- Use this option to quit PM Chaos. When you select it, the program will
- display a dialog box asking if you really want to quit; click on the
- :hp2.Yes:ehp2. button if you do.
- :p.
- You can also quit PM Chaos by selecting :hp2.Close:ehp2. from the system menu.
- .*
- .***************************************************
- .*
- :h1 res=310. The Options menu
- :p.
- The :hp2.Options:ehp2. menu contains the following choices:
- :ul.
- :li.:link reftype=hd res=311. Slow Motion:elink.
- :li.:link reftype=hd res=241. Delay Time:elink.
- :li.:link reftype=hd res=210. Colors:elink.
- :li.:link reftype=hd res=220. Set K :elink.
- :eul.
- .*
- .*
- .*
- :h1 res=311. Slow Motion
- :p.
- :i2 refid=Slow.toggling
- Use this option to turn :link reftype=hd res=240.slow motion mode:elink. on
- or off.
- :p.
- If there is a check mark next to this menu item, that means that
- slow motion mode has been selected. If there is no check mark, then
- slow motion mode has not been selected.
- :p.
- If a calculation is in progress, turning slow motion mode on or off will
- end it.
- .*
- .***************************************************
- .*
- :h1 res=320. The Range menu
- :p.
- The :hp2.Range:ehp2. menu contains the following choices:
- :ul.
- :li.:link reftype=hd res=232. Zoom In :elink.
- :li.:link reftype=hd res=231. Zoom Out :elink.
- :li.:link reftype=hd res=233. Set Ranges :elink.
- :eul.
- :p.:hp4.Related information: :ehp4.:p.
- :link reftype=hd res=230. General comments about the range. :elink.
- .*
- .*************************************************************
- .** Finally, key assignments. **
- .*************************************************************
- .*
- :h1 res=400. Key assignments
- :p.
- For on-line help, and for tasks like switching between windows,
- PM Chaos uses the same keys as any other Presentation
- Manager:link refid=TM reftype=fn.**:elink. program. Additionally,
- PM Chaos defines some accelerator keys of its own for commonly used
- tasks.
- :fn id=TM.
- Presentation Manager is a trademark of the IBM Corporation.
- :efn.
- .*
- :ul.
- :li.:link reftype=hd res=401. PM Chaos keys :elink.
- :li.:link reftype=hd res=402. Help keys :elink.
- :li.:link reftype=hd res=403. System and window keys :elink.
- :eul.
- .*
- .***************************************************
- .*
- :h1 res=401. PM Chaos key assignments
- .*:lines align=center.
- .*:hp4. PM Chaos keys: :ehp4.
- .*:elines.
- .*
- :p.
- :dl tsize=8 break=none compact.
- :dthd.:hp7.Key :ehp7.
- :ddhd.:hp7.Action :ehp7.
- :dt. Esc
- :dd. Stop!
- :dt. Alt+C
- :dd. Clear Screen
- :dt. Alt+X
- :dd. Exit
- :dt. C
- :dd. Colors
- :dt. K
- :dd. Set K
- :dt. <
- :dd. Zoom In
- :dt. >
- :dd. Zoom Out
- :dt. R
- :dd. Set Ranges
- :edl.
- .*
- .***************************************************
- .*
- :h1 res=402. On-line help key assignments
- :p.
- .*:lines align=center.
- .*:hp4. Help keys :ehp4.
- .*:elines.
- .*
- :dl tsize=12 break=none compact.
- :dthd.:hp7.Key :ehp7.
- :ddhd.:hp7.Action :ehp7.
- :dt. F1
- :dd. Get help
- :dt. F2
- :dd. Extended help (from within help)
- :dt. F9
- :dd. Keys help (from within help)
- :dt. F11
- :dd. Help index (from within help)
- :dt. Shift+F10
- :dd. Using help (from within help)
-
- :edl.
- .*
- .***************************************************
- .*
- :h1 res=403. System and window key assignments
- .*:lines align=center.
- .*:hp4. System and window keys :ehp4.
- .*:elines.
- :p.
- :dl tsize=5 break=all.
- .*:dthd.:hp4.Key :ehp4.
- .*:ddhd.:hp4.Action :ehp4.
- :dt. Alt+F9
- :dd. Minimize the window
- :dt. Alt+F10
- :dd. Maximize the window
- :dt. Alt+Esc
- :dd. Switch to the next program
- :dt. Ctrl+Esc
- :dd. Switch to the Task List
- :dt. Shift+Esc or Alt+Spacebar
- :dd. Go to or from the system menu
- :dt. F10 or Alt
- :dd. Go to or from the action bar
- :dt. Underlined letter
- :dd. Move among the choices on the action bar and pull-down menus
- :dt. Arrow keys
- :dd. Move among the choices on the action bar and pull-down menus
- :edl.
- .*
- .*
- .*
- :index.
- :euserdoc.
- .*
- .* The document per se has now ended.
- .* This last little bit of gunk is for the benefit of Emacs.
- .*
- .* Local Variables:
- .* mode: text
- .* comment-column: 0
- .* comment-start: ".*"
- .* comment-start-skip: "^\\.\\*"
- .* comment-end: ""
- .* End:
-
-