![\includegraphics[angle=-90,width=0.32\textwidth]{schema.ps.gz}](img2.png)
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Ralf Stephan
Copyright ©2000 Ralf Stephan
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, with the Invariant Sections being "About the first version", "First Version Thanks", "Conclusions about the first version", and "GNU Free Documentation License", with no Front-Cover Texts, and with no Back-Cover Texts.
A copy of the license is included in the section entitled "GNU Free Documentation License".
This version verbosely introduces the original code in Sections Board through Makefile . The Debugging Section deals with debugging of this
version but shouldn't provoke general interest. With few exceptions, the code
was written in the order you see it. Disclaimer: The order the stuff is
presented here should be no dogma for the reader's development work. R.S.,
April 2000
Tools used for pictures and text include but were not limited to noweb, LATEX, xfig, The Gimp, LATEX2HTML, and Amaya-2.2.
Kudos to all authors of the software I needed for this. R.S., April 2000
Picture a small ball on a planar slope, rolling down and hitting a nail of the same size, erectly sticking in the ground. Following that, there is a 50-50 chance that it will roll on down either of the two sides. Soon it will hit the next nail center, with the same chances of moving on to the left or right.
Presume that the nails are standing evenly-spaced in a triangular area, with
the first nail the top corner of the triangle, and on the symmetry axis. So
you can see rows of 1,2,3,4
nails, all symmetrical to the same
axis.
Now, if you let enough balls pass this parcourt, and collect them, where they fall, in tubes, you would get a picture of the so-called gaussian curve (referring to its discoverer) or bell curve (referring to its shape). The bell curve is ubiquitous in nature and/or is used extensively in statistics. Its mathematical formula is derived from the function in this figure.
Graphically, the user will see the whole area as a cartesian plane with pixel chunks replaced by images for nicer look. It suffices to have balls and nails on the board, other agents aren't needed for this demo.
Another issue would be speed: the demonstration should be timed good enough to be realistically and visually pleasing.
![\includegraphics[angle=-90,width=0.5\textwidth]{curve.ps.gz}](img4.png)
![\includegraphics[angle=0,width=4cm]{sshot2.ps.gz}](img6.png)
![\includegraphics[angle=0,width=2.5cm]{sshot4.ps.gz}](img7.png)
![\includegraphics[angle=0,width=4cm]{sshot3.ps.gz}](img8.png)
Board, the Balls, the Nails, the
Nail, the Ball:
ObserverSwarm
that can be replaced by a BatchSwarm, for example.
So Board handles the graphics as well as the geometry here, and
for that, it communicates with all other classes.
Nails is the class that, from the Board viewpoint,
contains information about the Nail agents.
Nail is an agent that does nothing. This means, its methods are
mostly empty.
Ball is an agent that acts through simple rules ("gravity",
"balance", "being stuck" etc.) in the environment.
Balls. We
might see other classes popping into existence as necessary.
Board, and to some
extent with each other.
Board.h and
Board.m, so the code chunks that follow go into these. In the
last subsection, we'll join all the chunks together.
GUISwarm which itself is a subclass of Swarm that
represents a general container for agents, giving them common time and memory,
so we inherit Board in the
<Board declaration head>= @interface Board: GUISwarm
within Board.h. To use GUISwarm like this, we also
need to
<Import the GUISwarm interface>= #import <simtoolsgui/GUISwarm.h>
The following code chunks describe the file Board.m. At the top,
the class header file is included and the implementation started.
<Import header, start implementation>= #import "Board.h" @implementation Board
To create the Board object, a class method is needed.
Class methods can be invoked by sending a message to the class itself, not to
one of the objects instantiated from it, and one of their usages are factory
methods. The method is implemented within Board.m and it simply
invokes the super class' create: method. Class methods are
prefixed with a plus character.
<Board::create definition>=
+ create: aZone
{
return [super create: aZone];
}
Board happens all in two
methods named buildObjects and buildActions,
respectively. First, a message is sent to the GUISwarm parent
class of Board to give it the opportunity to build its objects,
for example the controlPanel which is a globally accessible
object. Then we wait for the user to click a button on the control panel, and
quit if it's the Quit button.
<Handle control panel>=
[super buildObjects];
[controlPanel setStateStopped];
if ([controlPanel getState] == ControlStateQuit)
return nil;
Balls and Nails
must be instantiated. In a more sophisticated swarm simulation, one
would create an object (for example, a ModelSwarm) that separates
the display from the simulated world -- here, there is no such object, so
imports of the respective header files are necessary.
<Import Balls, Nails headers>= #import "Balls.h" #import "Nails.h"
Declare a handle at the top of the method for nails:
<nails declaration>= id nails;
And declare a handle as a private member of the Board class in
Board.h because it is needed later when scheduling is done.
<balls declaration>= id balls;
Now set the handles.
<Create Balls, Nails objects>= balls = [Balls create: [self getZone]]; nails = [Nails create: [self getZone]];
Board
are shown as pixmaps, this step can be skipped here (soon, we'll see that this is wrong so
expect the code to change a bit later).
So, the next thing to build is a Raster object and to draw it. It
seems safe to say that the Raster represents mainly the
simulation window frame and its colormap. The handle declaration goes into the
header file.
<worldRaster declaration>= id <ZoomRaster> worldRaster;
The string representation has the authority
for the board dimensions, only the worldRaster zoom factor is
adapted experimentally later. The rest of the
code should be self-explanatory.
<Create, set, draw worldRaster>=
worldRaster = [ZoomRaster createBegin: self];
SET_WINDOW_GEOMETRY_RECORD_NAME (worldRaster);
worldRaster = [worldRaster createEnd];
[worldRaster setZoomFactor: 4];
[worldRaster setWidth: [StringRepresentation getSizeX]
Height: [StringRepresentation getSizeY]];
[worldRaster setWindowTitle: "Balls and Nails"];
[worldRaster pack]; // draw the window.
Here, the first usage of createBegin: instead of
create: can be seen. Also, self is given as the
Zone. That is possible because Board inherits from
Zone through GUISwarm through
Swarm.
The message pair createBegin:/createEnd is used for
creating objects whenever a distinction is necessary between messages to
objects 'still not scheduled' and those to objects 'in schedule'. Messages in
between such pairs help swarm with doing simulation efficiently, and
might provide the user with improved memory usage stats in the future.
In other swarm applications, the grid containing the agents, as well as
all other non-graphical objects like values, is inside its own
Swarm to separate computation and graphics. But, as said, we put
it all into Board for convenience.
We choose a Grid2d that can contain arbitrary int values or
pointers. Nails and balls are pointers to the respective agents, and empty
space is 0.
The declaration is written at the buildObject method's top.
<Local world declaration>= id <Grid2d> world;
In the method's body, the grid is then created and sent to Balls
where it's needed by the agents.
<Create world grid>=
world = [Grid2d create: self
setSizeX: [StringRepresentation getSizeX]
Y: [StringRepresentation getSizeY]];
[balls buildObjects];
[nails buildObjects];
[balls setWorld: world];
The StringRepresentation has authority of the world´s size
and content. Its interface should be imported at the Board class
implementation´s top, too.
<Import StringRepresentation interface>= #import "StringRepresentation.h"
As the handle is used later when events are scheduled, its declaration as a
private member is put into the class header. According to the choice of the
grid, this will be an Object2dDisplay.
<boardDisplay declaration>= id <Object2dDisplay> boardDisplay;
The interfaces of the display and grid classes reside in
<space.h> so this header is best imported from the
Board header, too.
<Import space interfaces>= #import <space.h>
Let's create the display.
<Create world display>=
boardDisplay = [Object2dDisplay create: self
setDisplayWidget: worldRaster
setDiscrete2dToDisplay: world
setDisplayMessage: M(drawSelfOn:)];
Usually, the display will look through its grid and if there is an object, it
will be sent the drawSelfOn: message to display itself. Another
strategy would have been to give the grid a collection of to-be-displayed
objects.
buildObjects method:
<Board::buildObjects definition>=
- buildObjects
{
<nails declaration>
<Local world declaration>
<Handle control panel>
<Create Balls, Nails objects>
<Create, set, draw worldRaster>
<Create world grid>
<Create world display>
return self;
}
The method has to return an id because it has to conform to this
interface which is inherited from the Swarm superclass. It
doesn't seem a bad idea to generally return self so that messages
could be chain grouped.
buildActions, the main event loop of the simulation is
scheduled and, for that, an ActionGroup object is needed.
One can say that this is like a list of tasks to be worked on, with their own
schedule, e.g. every timestep of the simulation. It is possible to randomize
tasks in an ActionGroup by allowing them random order within one
step, but this is not useful with the main schedule. But
ActionGroups can be nested, and later some agent schedules can be
randomized if necessary.
The other object to be created is the displaySchedule itself; it
needs to know the frequency it's running on, and the ActionGroup
to schedule.
The handles of both objects are declared in the Board.h header
file:
<Action, schedule declarations>= id displayActions; id displaySchedule;
The reader might note that it's not strictly necessary to give a protocol that the handle conforms to. Known messages to known objects might be handled differently by swarm than those to unknown ones but there doesn't seem much overhead. A side effect of this is that the necessary imports can be kept out of the header file and put on top of the implementation file:
<Import ActionGroup, Schedule interfaces>= #import <activity.h>
First, the method sends a message to the super class of Board to
build the control panel and balls actions. Then it creates the first object
and adds the members of the action list. The first three actions cause the
content of the frame to be displayed efficiently -- no actual erase happens
but positional changes of the agents should be handled.
The last action consists of sending a message to the Tk library to render all graphical changes. Obviously, these actions have to happen in the right order on every step so they can't be randomized. The setting up of the schedule object completes this method.
<Board::buildActions definition>=
- buildActions
{
[super buildActions];
[balls buildActions];
displayActions = [ActionGroup create: self];
[displayActions createActionTo: worldRaster message: M(erase)];
[displayActions createActionTo: boardDisplay message: M(display)];
[displayActions createActionTo: worldRaster message: M(drawSelf)];
[displayActions createActionTo: actionCache message: M(doTkEvents)];
displaySchedule = [Schedule create: self setRepeatInterval: 1];
[displaySchedule at: 0 createAction: displayActions];
return self;
}
Schedule is
activated, as well as those of other objects that have one, including the
super class. The swarm context comes from the main function.
Nails don't need a schedule, they don't move.
<Board::activateIn definition>=
- activateIn: swarmContext
{
[super activateIn: swarmContext];
[balls activateIn: self];
[displaySchedule activateIn: self];
return [self getSwarmActivity];
}
The returned Activity object isn't used in this simulation.
<Board.m>= <Import ActionGroup, Schedule interfaces> <Import StringRepresentation interface> <Import header, start implementation> <Board::create definition> <Board::buildObjects definition> <Board::buildActions definition> <Board::activateIn definition> @end
and, from pieces all over the section, the interface file.
<Board.h>=
<Import the GUISwarm interface>
<Import space interfaces>
<Import Balls, Nails headers>
<Board declaration head>
{
<balls declaration>
<worldRaster declaration>
<boardDisplay declaration>
<Action, schedule declarations>
}
+ create: aZone;
- buildObjects;
- buildActions;
- activateIn: swarmContext;
@end
This completes the description of the Board class.
List of Balls, and activates
their scheduling. It handles messages from Board and uses the
StringRepresentation of the model start positions to set the
Ball positions.
Balls.hBalls.h looks like this:
<Balls.h>=
#import <objectbase/Swarm.h>
#import <collections.h>
@interface Balls: Swarm
{
id <List> theBalls;
id ballsActions, ballsSchedule;
}
+ create: aZone;
- buildObjects;
- setWorld: aWorld;
- buildActions;
- activateIn: swarmContext;
@end;
Balls.mBalls implementation draws resources from several other
classes. The file has the following structure 1:
<Balls.m>= #import <activity.h> #import "Balls.h" #import "Ball.h" #import "Position.h" #import "StringRepresentation.h" @implementation Balls <Balls::create definition> <Balls::buildObjects definition> <Balls::setWorld definition> <Balls::buildActions definition> <Balls::activateIn definition> @end
Creating the object consists of creating its superclass, a minimal create method.
<Balls::create definition>=
+ create: aZone
{
return [super create: aZone];
}
The list is created and filled within the buildObjects method.
The information is readily available from the
StringRepresentation of the initial board.
As the Position objects are never
dropped (to free their memory etc.) elsewhere, this has to be done here.
<Balls::buildObjects definition>=
- buildObjects
{
id pos;
theBalls = [List create: [self getZone]];
[StringRepresentation resetToChar: '0'];
while ((pos = [StringRepresentation getNextPos]) != nil)
{
Ball* ball = [Ball create: [self getZone]];
[ball setX: [pos getX] Y: [pos getY]];
[theBalls addFirst: ball];
[pos drop];
}
return self;
}
Readers might note that StringRepresentation behaves like an
iterator, returning all Position objects that can be linked to
the 0 character. It's also a class that consists entirely of
class methods. On another eMail tip by Paul E Johnson, the
List::addFirst method is used instead of addLast,
since the order of balls in the list doesn't matter.
The setWorld message is received from the board when
world creation is finished. Every single ball needs a handle to
it because they are assumed to access world independently. So we
send it with the setWorld message to all of them.
<Balls::setWorld definition>=
- setWorld: aWorld
{
[theBalls forEach: M(setWorld:) : aWorld];
return self;
}
Like in the Board implementation, there are Actions
and a Schedule to be built2.
<Balls::buildActions definition>=
- buildActions
{
ballsActions = [ActionGroup create: self];
[ballsActions createActionForEach: theBalls message: M(step)];
ballsSchedule = [Schedule createBegin: self];
[ballsSchedule setRepeatInterval: 1];
ballsSchedule = [ballsSchedule createEnd];
[ballsSchedule at: 0 createAction: ballsActions];
return self;
}
In the activateIn method, the schedule of all balls is added to
the caller's activity.
<Balls::activateIn definition>=
- activateIn: swarmContext
{
[ballsSchedule activateIn: swarmContext];
return self;
}
List of Nails, and sets their
positions. It handles messages from Board and uses the
StringRepresentation of the model start positions to set the
Nail positions.
The difference to Balls is that nails are never put into the
simulation schedule since they don't move, so there are no
buildActions and activateIn: methods needed. For
the same reason, nails need not access the world -- except for drawing the
first time but then they get it as parameter with the drawSelfOn:
message --, and so setWorld: isn't needed, as well.
The header file Nails.h looks like this:
<Nails.h>=
#import <objectbase/SwarmObject.h>
#import <collections.h>
@interface Nails: SwarmObject
{
id <List> theNails;
}
+ create: aZone;
- buildObjects;
@end;
And the implementation file can be adapted from Balls.m with the
abovementioned changes:
<Nails.m>=
#import "Nails.h"
#import "Nail.h"
#import "Position.h"
#import "StringRepresentation.h"
@implementation Nails
+ create: aZone
{
return [super create: aZone];
}
- buildObjects
{
id pos;
theNails = [List create: [self getZone]];
[StringRepresentation resetToChar: '1'];
while ((pos = [StringRepresentation getNextPos]) != nil)
{
id nail = [Nail create: [self getZone]];
[nail setX: [pos getX] Y: [pos getY]];
[theNails addLast: nail];
[pos drop];
}
return self;
}
@end
step message each turn. So, the header
looks like this:
<Ball.h>=
#import <objectbase/SwarmObject.h>
#import <space.h> // for Raster protocol
@interface Ball: SwarmObject
{
unsigned x,y;
id <Grid2d> world;
}
+ create: aZone;
- (void) setX: (unsigned) X Y: (unsigned) Y;
- setWorld: aWorld;
- (void) step;
- drawSelfOn: (id <Raster>) aRaster;
@end;
The implementation is straightforward but there is more to say about the
step and drawSelfOn: methods.
<Ball.m>=
#import <random.h>
#import "Ball.h"
@implementation Ball
+ create: aZone
{
return [super create: aZone];
}
- (void) setX: (unsigned) X Y: (unsigned) Y
{
x = X;
y = Y;
}
- setWorld: aWorld
{
world = aWorld;
return self;
}
<Ball::step definition>
<Ball::drawSelfOn definition>
@end
step method is the heart of its
behaviour. Balls are presented with a cartesian world consisting of other
balls, nails, and empty space. The world can (and should only)
be queried and set through the getObjectAtX:Y: and
putObject:atX:Y: methods.
So how to organize the logic within? Easy: get information, decide, move. For the balls, there seem to be several cases:
That's all. Here is the
<Ball::step definition>=
- (void) step
{
id pos1Object, pos2Object;
pos1Object = [world getObjectAtX: x Y: y+1];
if (pos1Object == nil)
{
[world putObject: nil atX: x Y: y];
[world putObject: self atX: x Y: y+1];
return;
}
pos1Object = [world getObjectAtX: x-1 Y: y+1];
pos2Object = [world getObjectAtX: x+1 Y: y+1];
if (pos1Object && pos2Object) return;
[world putObject: nil atX: x Y: y];
if (pos1Object)
[world putObject: self atX: x+1 Y: y+1];
else if (pos2Object)
[world putObject: self atX: x-1 Y: y+1];
else
if ([uniformIntRand getIntegerWithMin: 0 withMax: 1])
[world putObject: self atX: x-1 Y: y+1];
else
[world putObject: self atX: x+1 Y: y+1];
}
drawPoint message to the raster doesn't suffice. The pixmap has
to be loaded from a file, and it should be taken care that this happens only
once. So, the static handle ballPixmap is used for holding it.
Remember, all static variables exist only once in memory, and are initialized
to 0/nil, so the following idiom works nicely.
<Ball::drawSelfOn definition>=
- drawSelfOn: (id <Raster>) aRaster
{
static id ballPixmap;
if (ballPixmap == nil)
{
ballPixmap = [Pixmap createBegin: [self getZone]];
[ballPixmap setDirectory: [arguments getAppDataPath]];
[ballPixmap setFile: "ball.png"];
ballPixmap = [ballPixmap createEnd];
[ballPixmap setRaster: aRaster];
}
[aRaster draw: ballPixmap X: x Y: y];
return self;
}
Ball´s methods is needed. This is the header:
<Nail.h>=
#import <objectbase/SwarmObject.h>
@interface Nail: SwarmObject
{
unsigned x,y;
}
+ create: aZone;
- (void) setX: (unsigned) x Y: (unsigned) y;
- drawSelfOn: aWorld;
@end;
and here goes the implementation:
<Nail.m>=
#import <gui.h>
#import "Nail.h"
@implementation Nail
+ create: aZone
{
return [super create: aZone];
}
- (void) setX: (unsigned) X Y: (unsigned) Y
{
x = X;
y = Y;
}
- drawSelfOn: (id <Raster>) aRaster
{
static id nailPixmap;
if (nailPixmap == nil)
{
nailPixmap = [Pixmap createBegin: [self getZone]];
[nailPixmap setDirectory: [arguments getAppDataPath]];
[nailPixmap setFile: "nail.png"];
nailPixmap = [nailPixmap createEnd];
[nailPixmap setRaster: aRaster];
}
[aRaster draw: nailPixmap X: x Y: y];
return self;
}
@end
<StringRepresentation.h>=
#import "Position.h"
@interface StringRepresentation
{}
+ (unsigned) getSizeX;
+ (unsigned) getSizeY;
+ (void) resetToChar: (char) aChar;
+ (Position*) getNextPos;
@end;
The implementation file starts with the actual string array which serves as the database for the class, and can be easily changed with any fixed-width font text editor.
<SR database>=
#import "StringRepresentation.h"
#include <string.h>
@implementation StringRepresentation
static char *str[] = {
" 100000000000001 ",
" 110000000000011 ",
" 1100000000011 ",
" 11000000011 ",
" 110000011 ",
" 1100011 ",
" 11011 ",
" ",
" 1 ",
" 1 1 ",
" 1 1 1 ",
" 1 1 1 1 ",
" 1 1 1 1 1 ",
" 1 1 1 1 1 1 ",
" 1 1 1 1 1 1 1 ",
" 1 1 1 1 1 1 1 1 ",
" ",
"1 1 1 1 1 1 1 1 1 1",
"1 1 1 1 1 1 1 1 1 1",
"1 1 1 1 1 1 1 1 1 1",
"1 1 1 1 1 1 1 1 1 1",
"1 1 1 1 1 1 1 1 1 1",
"1 1 1 1 1 1 1 1 1 1",
"1111111111111111111"};
Outside of the resetToChar method, there are additional statics
declared, and set within for later use.
<SR resetToChar definition>=
static char activeChar = '0';
static int currentX, currentY;
+ (void) resetToChar: (char) aChar
{
activeChar = aChar;
currentX = currentY = 0;
}
getNextPos searches through the string array to find the position
of the next occurence of activeChar, returning a
Position object or nil.
<SR getNextPos definition>=
+ (Position*) getNextPos
{
char c;
while (currentY < sizeof(str)/sizeof(char*))
{
while ((c = str[currentY][currentX++]) != 0)
if (c == activeChar)
return [Position create: scratchZone
withX: currentX Y: currentY];
currentX = 0;
++currentY;
}
return nil;
}
The last two methods calculate the dimensions of the representation.
<SR dimensions calculation>=
- (unsigned) getSizeX
{
int i, max=0;
for (i=0; i<sizeof(str)/sizeof(char*); i++)
{
int len = strlen (str[i]);
if (len > max) max = len;
}
return max;
}
- (unsigned) getSizeY { return sizeof(str)/sizeof(char*); }
At last, the whole file:
<StringRepresentation.m>= <SR database> <SR resetToChar definition> <SR getNextPos definition> <SR dimensions calculation>
<Position.h>=
#import <objectbase/SwarmObject.h>
@interface Position: SwarmObject
{
unsigned theX, theY;
}
+ create: aZone withX: (unsigned) x Y: (unsigned) y;
- (unsigned) getX;
- (unsigned) getY;
@end;
<Position.m>=
#import "Position.h"
@implementation Position
+ create: aZone withX: (unsigned) x Y: (unsigned) y
{
Position* obj;
obj = [super create: aZone];
obj->theX = x;
obj->theY = y;
return obj;
}
- (unsigned) getX { return theX; }
- (unsigned) getY { return theY; }
main.m is the entrance into the simulation, and the only thing to
do here is to initSwarm and create the Board.
<main.m>=
#import <simtools.h> // for initSwarm
#import "Board.h"
int main (int argc, const char **argv)
{
Board *theBoard;
initSwarm (argc, argv);
theBoard = [Board create: globalZone];
[theBoard buildObjects];
[theBoard buildActions];
[theBoard activateIn: nil];
[theBoard go];
return 0;
}
Makefile consists of the variable part and several targets.
<Makefile>= <Makefile variables> <all target> <src target> <dvi target> <html target> <tarball target>
The first part defines variables to be used later. This code could be adapted easily for other apps by replacing variable content -- it suffices to set the application name, and its objects.
<Makefile variables>= ifeq ($(SWARMHOME),) # please set your SWARMHOME in your environment or put it here: SWARMHOME= endif BUGADDRESS=ralf@ark.in-berlin.de APPLICATION=bell OBJECTS=main.o Board.o Balls.o Nails.o Ball.o Nail.o Position.o StringRepresentation.o APPLIBS= APPDIR=$(APPLICATION) SOURCES=$(addsuffix .m, $(basename $(OBJECTS))) HEADERS=$(addsuffix .h, $(basename $(OBJECTS))) HEADERS:=$(filter-out main.h,$(HEADERS)) PATCHES:=$(shell noroots $(APPLICATION).nw | grep patch | sed 's/[<>]//g'\ | sort +1 -n -t-)
After that, the generic swarm Makefile is included and the
all target set.
<all target>= include $(SWARMHOME)/etc/swarm/Makefile.appl all: $(APPLICATION)
For the src target, several noweb tools and
patch are used to extract the Objective-C source.
<src target>=
src:
@echo extracting original source files
@for i in $(SOURCES) $(HEADERS) $(PATCHES);\
do notangle -R$$i $(APPLICATION).nw |cpif $$i;\
done
@for i in $(PATCHES); do echo $$i:; patch <$$i; done
@echo done
To produce the dvi file, the LATEX source is extracted and compiled, and everything needed put into the DVI directory.
<dvi target>=
dvi:
@mkdir -p DVI
rm -f $(APPLICATION).aux $(APPLICATION).toc
noweave -n -x -latex $(APPLICATION).nw >body.tex
latex $(APPLICATION).tex
latex $(APPLICATION).tex
latex $(APPLICATION).tex
cp $(APPLICATION).dvi *.ps.gz *.ps.bb DVI
The HTML page is produced with LATEX2HTML, put into the HTML directory, and made HTML-4.0 (transitional) conformant with Amaya-2.2.
<html target>=
html:
rm -rf $(APPLICATION) HTML
mkdir HTML
noweave $(NOWEBOPTS) -latex+html $(APPLICATION).nw >body.tex
latex2html -split 0 -no_navigation $(APPLICATION).tex
cp $(APPLICATION)/$(APPLICATION).html $(APPLICATION)/*.png \
$(APPLICATION)/$(APPLICATION).css HTML
rm -rf $(APPLICATION)
amaya HTML/$(APPLICATION).html
For the tarball, a helper directory is created and the wanted files copied into that before archiving.
<tarball target>=
tarball:
rm -rf $(APPDIR)
mkdir $(APPDIR)
cp *.h *.m *.png *.ps.* Makefile $(APPLICATION).tex\
$(APPLICATION).nw README $(APPDIR)
cp -dpR HTML DVI $(APPDIR)
tar cvfz $(APPDIR).tar.gz $(APPDIR)
rm -rf $(APPDIR)
patches-1
and so on. Patches are presented in unified format which should be the
easiest to read. You can get yourself such patches by using revision control
systems like cvs or rcs, or by giving the command
diff -u oldfile newfile. In the src target of the Makefile section the
corresponding steps are shown to apply the patches to the hitherto written
first version files.
bt command) reveals it happened when
trying to setRaster in Ball::drawSelfOn:, and
further examination shows that, inside swarm, a colormap is accessed but we
never set the handle. This shows the argumentation earlier was flawed, the reason being that
there is always a colormap needed (in other cases, swarm issues a warning but
it did not in this case so a bug report with patch was sent to the bug
address).
The latter means we have to patch the start of
Board::buildObjects and include code for creating the
colormap, setting a number of colors, and giving the colormap to
worldRaster.
<patch-1>=
--- Board.m
+++ Board.m
@@ -11,11 +11,16 @@
{
id nails;
id <Grid2d> world;
-
+ id colormap;
+ int i;
+
[super buildObjects];
[controlPanel setStateStopped];
if ([controlPanel getState] == ControlStateQuit)
return nil;
+ colormap = [Colormap create: self];
+ for (i=0; i<32; i++)
+ [colormap setColor: i ToRed: 0 Green: 0 Blue: 0];
balls = [Balls create: [self getZone]];
nails = [Nails create: [self getZone]];
worldRaster = [ZoomRaster createBegin: self];
@@ -24,6 +29,7 @@
[worldRaster setZoomFactor: 4];
[worldRaster setWidth: [StringRepresentation getSizeX]
Height: [StringRepresentation getSizeY]];
+ [worldRaster setColormap: colormap];
[worldRaster setWindowTitle: "Balls and Nails"];
[worldRaster pack]; // draw the window.
world = [Grid2d create: self
<patch-2>=
--- Board.m
+++ Board.m
@@ -26,7 +26,7 @@
worldRaster = [ZoomRaster createBegin: self];
SET_WINDOW_GEOMETRY_RECORD_NAME (worldRaster);
worldRaster = [worldRaster createEnd];
- [worldRaster setZoomFactor: 4];
+ [worldRaster setZoomFactor: 16];
[worldRaster setWidth: [StringRepresentation getSizeX]
Height: [StringRepresentation getSizeY]];
[worldRaster setColormap: colormap];
We see the nail pixmaps are missing, but the balls are at the right places.
Including printf statements into the
Balls/Nails code reveals the nails are created with
the correct positions. Switching the graphics file doesn't matter: no nail
ever gets the drawSelfOn: message but for what reason?
It turns out that nail objects are never put into the world, which is the case
with balls accidentally, in their step method. A solution is to
add a setWorld: message to Nails as well, and call
it from the Board code, so we have the following patches.
![\includegraphics[angle=-90,width=4cm]{sshot1.ps.gz}](img9.png)
<patch-3>=
--- Board.m
+++ Board.m
@@ -39,6 +39,7 @@
[balls buildObjects];
[nails buildObjects];
[balls setWorld: world];
+ [nails setWorld: world];
boardDisplay = [Object2dDisplay create: self
setDisplayWidget: worldRaster
setDiscrete2dToDisplay: world
<patch-4>=
--- Nails.m
+++ Nails.m
@@ -25,4 +25,10 @@
}
return self;
}
+
+- setWorld: aWorld
+{
+ [theNails forEach: M(setWorld:) : aWorld];
+ return self;
+}
@end
<patch-5>=
--- Nail.m
+++ Nail.m
@@ -1,4 +1,5 @@
#import <gui.h>
+#import <space.h>
#import "Nail.h"
@implementation Nail
@@ -30,6 +31,12 @@
[aRaster draw: nailPixmap X: x Y: y];
+ return self;
+}
+
+- setWorld: (id <Grid2d>) aWorld
+{
+ [aWorld putObject: self atX: x Y:y];
return self;
}
@end
Fortunately, this bug leads us to the fact that Ball doesn't put
itself into world, too, so finding the solution for the next bug
at once with the patch:
<patch-6>=
--- Ball.m
+++ Ball.m
@@ -1,4 +1,5 @@
#import <random.h>
+#import <space.h>
#import "Ball.h"
@implementation Ball
@@ -17,6 +18,7 @@
- setWorld: aWorld
{
world = aWorld;
+ [world putObject: self atX: x Y:y];
return self;
}
<patch-7>=
--- StringRepresentation.m
+++ StringRepresentation.m
@@ -4,7 +4,7 @@
@implementation StringRepresentation
static char *str[] = {
+" 100000000000001 ",
-" 100000000000001 ",
" 110000000000011 ",
" 1100000000011 ",
" 11000000011 ",
step message, so it turns out the position that ball
knows of itself isn't changed in step. The patch is easy.
<patch-8>=
--- Ball.m
+++ Ball.m
@@ -30,7 +30,7 @@
if (pos1Object == nil)
{
[world putObject: nil atX: x Y: y];
+ [world putObject: self atX: x Y: ++y];
- [world putObject: self atX: x Y: y+1];
return;
}
@@ -41,14 +41,14 @@
[world putObject: nil atX: x Y: y];
if (pos1Object)
+ [world putObject: self atX: ++x Y: ++y];
- [world putObject: self atX: x+1 Y: y+1];
else if (pos2Object)
+ [world putObject: self atX: --x Y: ++y];
- [world putObject: self atX: x-1 Y: y+1];
else
if ([uniformIntRand getIntegerWithMin: 0 withMax: 1])
+ [world putObject: self atX: --x Y: ++y];
- [world putObject: self atX: x-1 Y: y+1];
else
+ [world putObject: self atX: ++x Y: ++y];
- [world putObject: self atX: x+1 Y: y+1];
}
- drawSelfOn: (id <Raster>) aRaster
{
<patch-9>= --- StringRepresentation.m +++ StringRepresentation.m @@ -27,6 +27,13 @@ "1 1 1 1 1 1 1 1 1 1", "1 1 1 1 1 1 1 1 1 1", "1 1 1 1 1 1 1 1 1 1", +"1 1 1 1 1 1 1 1 1 1", +"1 1 1 1 1 1 1 1 1 1", +"1 1 1 1 1 1 1 1 1 1", +"1 1 1 1 1 1 1 1 1 1", +"1 1 1 1 1 1 1 1 1 1", +"1 1 1 1 1 1 1 1 1 1", +"1 1 1 1 1 1 1 1 1 1", "1111111111111111111"}; static char activeChar = '0'; static int currentX, currentY;
bell with the -s option. Even the speed of the
simulation is nice, on faster machines one would manually step through it.
What remains? At this point in time, there are still no illustrations done, so we'll finish the documentation with that and a thorough review. But the code flow that has kept us in a linear motivation, same as with the patient reader's attention hopefully, has crystallized into a small demo application that works with swarm-2 (other versions not tested). Not more did we want. R.S., April 2000
<fdl.txt>=
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This document was generated using the LaTeX2HTML translator Version 98.2 beta6 (August 14th, 1998)
Copyright © 1993, 1994, 1995, 1996, Nikos Drakos, Computer
Based Learning Unit, University of Leeds.
Copyright © 1997, 1998, Ross Moore, Mathematics
Department, Macquarie University, Sydney.
The command line arguments were:
latex2html -split 0 -no_navigation bell.tex
The translation was initiated by Ralf Stephan on 2000-05-10
step method being realistic with a
randomized schedule, we would have to add security that balls don't interfere
in the sieve part, which was too much for this little demo.