• This role is for a QA Engineer for our Budapest software engineering and quality assurance team. This candidate will be responsible for test planning, development and execution as part of our next-generation equity portfolio analytics product-development team.
• This role would suit a person who has experience in using HP/Mercury QTP, Test Director, VB and MATLAB to test highly quantitative applications products, and who has a broad appreciation of the institutional investment domain. The person will be expected to work closely with our software engineers in Budapest and with our product managers and application developers in multiple global locations. We are seeking someone with an inquisitive nature, attention to detail,  a keen interest in application quality, and experience with test-driven development practices.

Requirements:

• Bachelors Degree in Computer Science or related discipline. Masters Degree preferred.
• Quality Assurance engineering experience on the Windows XP/Vista platform.
• Experience with test-case development, test automation, HP/Mercury QTP.
• Excellent communications skills and English fluency
• Proven ability to work independently and within a team environment.

laszlo_spiller@kellyservices.hu

% cd /apps/matlab/r2006b/etc
The folder might be different from yours. But you need to go to the /etc folder and then run lmstat -a to show all info.
% ./lmstat -a

Type ./lmstat --help if you want to use other options

Gampang bangeeeee…ttzz!

Pertama cari software yang namanya “MATLAB”, mudah loh nyarinya, bisa nyari di tempat software, nyari ke temen dekat anda atau berkunjung ke www.mathworks.com

Langkah kedua, install tuh software jangan di kukut ( soalnya ga bakalan beranak ato jadi duit ), kalo udah di install jangan di diemin juga, so…. Cepet bertindak. Caranya klik star >> all program >> matlab.

Langkah ke tiga lihat soal integral yang ada baik-baik, misalnya soal integralnya seperti ini :            [gallery](“…<:’+)(&%$#@..!!”)

Tenang sie, ngak usah panic, kan ada matlab !!

Langkah ke empat :

Di command window pada matlab ketik :’

            >> y = inline (' x.^6+x.^5-x.^3+x.^2-x') terus enter, naaah hasilnya :

y =

               Inline function:

               y(x) = x.^6+x.^5-x.^3+x.^2-x

perintah inline di matlab yaitu untuk menampung fungsi integral, sedangkan untuk menghitung nilai integralnya sendiri matlab menyediakan fungsi quad. Ok!!! Setelah integralnya di simpan di variable y, langkah selanjutnya ketikan perintah ini:

            >> hasil = quad(y,-1,2)

              hasil =

    26.6786

(y,-1,2) artinya y = fungsi integral yang diroses, -1 = batas bawah dari integral, dan 2 = batas atas dari integral.

Waooww.. selesai sudaaah…he..he…

aku masih lagi dalam keadaan malas. malas nak pergi belajar. malas nak daftar semester baru di UTP. aku selesa hidup mcm 2 bulan lepas. tidur, makan, bangun, main dan tidur lagi. walaupun tidak berduit, tapi hati aku tenang. hidup kat UTP ni sengsara, otak kena jalan 24/7. tambah-tambah aku dah semester terakhir di UTP.

lihat saja kotak-kotak itu, malas nak kemas. malas nak packing...

kalau boleh nak duduk rileks-rileks je...

dah la tu, semester ni aku kena belajar MatLab. apa kejadah bendanya pun aku tatau. tapi demi fyp aku, aku terpaksa memaksa diri aku untuk beli software original pirated (ubah gaya hidup). yang tu je aku mampu. aku download ebooks kat laman web untuk mempelajari dengan lebih mendalam tentang MatLab (Read : Liar!) dan seterusnya berjaya men-graduate-kan diri. hehe...

tapi-kan, aku ada jugak tengok DEBAT antara Anwar dgn Shabery tadi. dah sah-sah la karisma dan kepimpinan Anwar yang mengatasi Shabery. tapi ada gak 1-2 soalan yang Anwar tak jawab. biasalah, masa terhad, ataupun memang Anwar takleh jawab. dan ada betulnya kata Shabery tadi. Anwar dulu pun orang B*b* Negara jugak (Read : BN), dia pun pernah kutuk Nik Aziz gak, ada gak masalah dia dgn empangan Pergau dulu. Tapi, sekarang dia dah berubah, so hopefully, dia akan terus memacu Malaysia ke arah yang lebih baik.

aku tatau lah kenapa mamat Shabery tu. tak reti-reti, ada 2 benda yang dapat aku simpulkan tentang kebodohan mamat ni:

1. Si Anwar bukan salahkan PETRONAS atau nak guna Dana PETRONAS. si Anwar tu ckp, pengurusan DANA NEGARA yang tidak cekap dan Pemimpin-pemimpin B*b* Negara yang patut dipersalahkan, lemah!
2. Jangan serang peribadi, jangan serang peribadi! walaupun aku ada jugak bersetuju sikit-sikit. Ia mengingatkan kita bagaimana Anwar serang PAS masa dia jadi tali barut B*b* Negara dulu-dulu.

tapi kan, kenapa mulut Shabery tu berbuih-buih. kat bahagian tepi mulut dia. GELI AKU TENGOK! eeeee!

oh, mesej baru aku terima :

JAWATAN KOSONG : MENTERI PENERANGAN MALAYSIA

denggg!~

Download Link:

Numerical_Computing_with_MATLAB_-_Cleve_Moler.pdf

Download Link:

Applied_Numerical_Methods_Using_MATLAB_-_Yang_Cao_Chung_and_Morris.pdf

Once I faced a license problem with MATLAB, which cost me much more time than it should be to figure it out. There's no license manager, say, lm/ folder installed, therefore I've noway to lmdown or lmstart. I thought there's some files missed during installation or the installation isn't completely successful. I uninstalled MATLAB, reinstalled it, but nothing happened. Today, I just asked someone whether the license has expired since it was passed to me. No surprise or much surprise, the answer is yes. So I'm now having the new license on and it starts working finely. It's just that this time my MATLAB doesn't need lm command anymore...

Whatever, my iMac is setup now, no matter how well the X11 part is functioning and that's the whole story of couple days' struggling. I hate it!

• XTICKLABEL_ROTATE, par Brian Katz
• XTICKLABEL_ROTATE90, par Denis Gilbert
• Rotate XTick Labels for multi-axes, par Peter Platzer

---------------

Comment mettre une étiquette à mes points ?

x=rand(3,1);
y=rand(3,1);

figure
plot(x,y,'r+');

str=num2str([1:numel(x)].','%1d'); % ATTENTION le premier argument de NUM2STR doit être un vecteur colonne
text(x+0.01,y+0.01,str) % Le décalage de 0.01 est arbitraire ici.
------------
omment tracer une ligne dont la couleur varie ?
x = rand(3,1);
y = rand(3,1);

figure
subplot(2,1,1)
plot(x,y)

subplot(2,1,2)

patch('xdata',[x;x(end:-1:1)],...
      'ydata',[y;y(end:-1:1)],...
      'facecolor','interp', ...
      'edgecolor','interp',...
      'facevertexcdata',[y;y(end:-1:1)])
-------------
omment animer le tracé d'une courbe ?
% Génération des données
th=0:0.02:10*pi;
y=sin(th);

% Création de l'objet Figure contenant les tracés
fig=figure;

% Première objet Axes où est tracée la courbe directe
subplot(2,1,1)
% Tracé de la courbe
plot(th,y,'r-')
% Ajustement des limites de l'objet Axes
xlim([min(th) max(th)])
ylim([min(y) max(y)])

% Second objet Axes où est tracée la courbe animée
subplot(2,1,2)

% Modification de la propriété DoubleBuffer de l'objet Figure pour
% éviter le clignotement de la fenêtre
% NECESSAIRE POUR TOUTE ANIMATION
set(fig,'doublebuffer','on')

% Tracé du premier point de la courbe
% et récupération de l'identifiant (handle) p de l'objet Line crée.
p=plot(th(1),y(1),'r-');
% Ajustement des limites de l'objet Axes
xlim([min(th) max(th)])
ylim([min(y) max(y)])

% On boucle sur le nombre de points à tracer. 
% On démarre à 2 puisque le premier est déjà tracé
for n=2:numel(th)

  % Ajout des points de la courbe au fur et à mesure
  % en utilisant la combinaison SET + identifiant (handle)
  set(p,'xdata',th(1:n),'ydata',y(1:n));
  % Forçage de l'affichage du tracé
  drawnow

end
-------------
Comment récupérer les valeurs de données tracées ?
Dans tous les cas, il faut utiliser la fonction FINDOBJ pour récupérer l'identifiant de l'objet dont on veut
		récupérer les données.

Pour les objets de type Line (nuage de points ou lignes), Surface ou Mesh, on récupère les propriétés XDATA, YDATA et ZDATA

Pour les objets de type Image, on récupère la propriété CDATA

Pour les objets de type Patch, on récupère, soit les propriétés XDATA, YDATA et ZDATA, soit les propriétés VERTICES et FACES


[X,Y,Z] = peaks(20)
surf(X,Y,Z);

h=findobj('type','surf');
xx=get(h,'xdata')
yy=get(h,'ydata')

zz=get(h,'zdata')
--------------------
Comment redimensionner une image ?
La première solution consiste à utiliser la fonction IMRESIZE contenue dans l'Image Processing Toolbox.

La deuxième solution utilise l'indexage des matrices. Puisqu'une
image est une matrice 2D ou 3D (RGB), il est très simple de diminuer la
taille d'une image en jouant sur l'indexage. Par exemple, pour diminuer
par deux la taille d'une image 2D, il suffit de ne conserver qu'un pixel sur deux


img=rand(150,200); % Une image 2D aléatoire
size(img)

ans =

   150   200

img=img(1:2:end,1:2:end);

size(img)

ans =

    75   100

--------Pour une image 3D (RGB), le code devient :
img=rand(150,200,3); % Une image 3D (RGB) aléatoire
size(img)

ans =

   150   200     3

img=img(1:2:end,1:2:end,:);

size(img)

ans =

    75   100     3
-----
On remarque que cette solution utilisant l'indexage se limite à des facteurs de réductions/agrandissement entier.

La troisième solution utilise les fonctions d'interpolation.

Soit INTERP2 pour diminuer par deux la taille d'une image 2D :
img = rand(150,200); % Une image 2D aléatoire
size(img)

ans =

   150   200

[c,r ] = size(img); % Récupération des 2 dimensions de l'image

[ci,ri] = meshgrid(1:2:r,1:2:c); % Génération de la grille d'interpolation

img = interp2(img,ci,ri); % Interpolation des valeurs des pixels

size(img)

ans =

    75   100

Soit INTERP3 pour diminuer par deux la taille d'une image 3D :
img = rand(150,200,3); % Une image 3D (RGB) aléatoire
 size(img)

ans =

   150   200     3

[c,r,p] = size(img); % Récupération des 3 dimensions de l'image

[ci,ri,pi] = meshgrid(1:2:r,1:2:c,1:p); % Génération de la grille d'interpolation

img = interp3(img,ci,ri,pi); % Interpolation des valeurs des pixels du plan R

size(img)

 ans =

ans =

    75   100     3

f,v]=isosurface (3Dmatrix,0);
translated to vrml with a simple script:

...
[fid,errmsg] = fopen('mymodel.wrl','w+');
...

----

fprintf(fid,' coord Coordinate {\n');
fprintf(fid,' point [\n');

for i=1:size (v,1)
fprintf(fid,'%f ',v(i,1)/500);
fprintf(fid,'%f ',v(i,2)/500);
fprintf(fid,'%f ',v(i,3)/500);
fprintf(fid,'\n');
end

fprintf(fid,' ]#Point\n');
fprintf(fid,' }#Coordinate\n');
fprintf(fid,' index[\n');

for i=1:size (f,1)
fprintf(fid,'%d ',f(i,1)-1);
fprintf(fid,'%d ',f(i,2)-1);
fprintf(fid,'%d ',f(i,3)-1);
fprintf(fid,'\n');
end

fprintf(fid,' ]#index\n');

...

fclose (fid);

Will you please show some (first ten lines - max .1kB) of the result?

unfortunately 30 megabytes for a 218x218x128 image!

The wrl file is not an image, it is the geometry and lighting.
You are sending the browser (the program that runs the .wrl file

(sets of x,y,z vertex values along with the info to make them
into triangles and lights that become pixels.

http://www.web3d.org/x3d/specifications/ISO-IEC-19776-X3DEncodings-XML-ClassicVRML/

that's too much (for both speed and memory), even because i want to
deal with much bigger matrix!

Great, we all want that.

ref: http://newsgroups.derkeiler.com/Archive/Comp/comp.lang.vrml/2007-08/msg00007.html

You need not have any substantial knowledge of the VRML format to use the VRML authoring tools to create virtual worlds. However, it is useful to have a basic knowledge of VRML scene description. This helps you to create virtual worlds more effectively, and gives you a good understanding of how the virtual world elements can be controlled using the Virtual Reality Toolbox.

This section is an introduction to VRML. For more information, refer to the VRML97 Reference. This reference is available online at http://www.web3d.org.

In VRML, a 3-D scene is described by a hierarchical tree structure of objects (nodes). Every node in the tree represents some functionality of the scene. There are 54 different types of nodes. Some of them are shape nodes (representing real 3-D objects), and some of them are grouping nodes used for holding child nodes. Here are some examples:

• Box node -- Represents a box in a scene.
• Transform node -- Defines position, scale, scale orientation, rotation, translation, and children of its subtree (grouping node).
• Material node -- Corresponds to material in a scene.
• DirectionalLight node -- Represents lighting in a scene.
• Fog node -- Allows you to modify the environment optical properties.
• ProximitySensor node -- Brings interactivity to VRML97. This node generates events when the user enters, exits, and moves within the defined region in space.

Each node contains a list of fields that hold values defining parameters for its function.

Nodes can be placed in the top level of a tree or as children of other nodes in the tree hierarchy. When you change a value in the field of a certain node, all nodes in its subtree are affected. This feature allows you to define relative positions inside complicated compound objects.

You can mark every node with a specific name by using the keyword DEF in the VRML scene syntax. For example, the statement DEF MyNodeName Box sets the name for this box node to MyNodeName. You can only access the fields of those nodes that you name in a virtual world.

In the following example of a simple VRML file, two graphical objects are modeled in a 3-D scene: A floor is represented by a flat box with a red ball above it. Note that VRML file is a readable text file that you can write in any text editor.

• #VRML V2.0 utf8
  # This is a comment line
  WorldInfo {
    title "Bouncing Ball"
  }
  Viewpoint {
    position 0 5 30
    description"Side View"
  }
  DEF Floor Box {
    size 6 0.2 6
  }
  DEF Ball Transform {
    translation 0 10 0
    children Shape {
      appearance Appearance {
        material Material {
          diffuseColor 1 0 0
        }
      }
      geometry Sphere {
      }
    }
  }

The first line is the VRML header line. Every VRML file must start with this header line. It indicates that this is a VRML 2 file and that the text objects in the file are encoded according to the UTF8 standard. You use the number sign (#) to comment VRML worlds. Everything on a line after the # sign is ignored by a VRML viewer, with the exception of the first header line.

Most of the box properties are left at their default values -- distance from the center of coordinate system, material, color, and so on. Only the name Floor and the dimensions are assigned to the box. To be able to control the position and other properties of the ball, it is defined as a child node of a Transform type node. Here, the default unit sphere is assigned a red color and a position 10 m above the floor. In addition, the virtual world title is used by VRML viewers to distinguish between virtual worlds. A suitable initial viewpoint is defined in the virtual world VRML file.

When displayed in V-Realm builder, the floor and red ball look like

The Virtual Reality Toolbox includes many features for you to create and visualize dynamic systems. It also provides real-time virtual interaction with dynamic models.

This section includes the following topics that describe these features:

• VRML Support --Use VRML to define a virtual world
• MATLAB Interface -- Control the virtual world from the MATLAB interface
• Simulink Interface -- Use Virtual Reality Toolbox blocks to connect your Simulink model to a virtual world
• VRML Viewers -- View your virtual world with the Virtual Reality Toolbox viewer or your Web browser
• VRML Editor -- Create virtual worlds using a VRML authoring tool or text editor
• Real-Time Workshop Support -- Support for simulations that use code generated by Real-Time Workshop
• SimMechanics Support -- View the behavior of your SimMechanics model in a virtual world
• Hardware Support -- Functions for using special hardware devices
• Client-Server Architecture -- Provide client-server architecture for a single computer or network operation

V-Realm Builder 2 is a flexible, graphically oriented tool for 3-D editing and is available for Windows operating systems only. It is a native VRML authoring tool that provides a convenient interface to the VRML syntax. Its primary file format is VRML. Its graphical interface (GUI) offers not only the graphical representation of a 3-D scene and tools for interactive creation of graphical elements, but also a hierarchical tree-style view (tree viewer) of all the elements present in the virtual world.

These structure elements are called nodes. V-Realm Builder lists the nodes and their properties according to their respective VRML node types, and it supports all 54 VRML97 types. For each type of node there is a specific tool for convenient modification of the node parameters. You can access node properties in two ways:

• Using dialog boxes accessible from the tree viewer
• Directly, using a pointing device

In many cases, it is easier to use the tree viewer to access nodes because it can be difficult to select a specific object in a 3-D scene. The tree view also lets you easily change the nesting levels of certain nodes to modify the virtual world according to your ideas. In the tree viewer, you can give the nodes unique names -- a feature necessary for working with Virtual Reality Toolbox.

In addition to a typical general VRML viewer functionality, Orbisnap offers the following features:

*Managing virtual scene viewpoints
*Saving VRML files

* Server mode
*Ability to connect to a remote server running Virtual Reality Toolbox  (Matlab ©) and display virtual worlds served by this server .

http://www.orbisnap.com

http://www.orbisnap.com/download2.html

-----------------------------

Orbisnap requires OpenGL capable graphics adapter, preferably with 3D hardware acceleration

Operating System

Processors
32-bit Windows XP, Windows 2000, Windows Vista, Windows Server 2003

Intel Pentium III, IV, Xeon, Pentium M
AMD Athlon, Athlon XP, Athlon MP
64-bit Windows XP, Windows 2000, Windows Vista, Windows Server 2003

Intel EMT64 processors
AMD64 processors
32-bit Linux Kernel 2.4.x and glibc 2.3.4 and above,
32-bit Linux Kernel 2.6.x and glibc 2.3.4 and above

Intel Pentium III, IV, Xeon, Pentium M
AMD Athlon, Athlon XP, Athlon MP
64-bit Linux Kernel 2.4.x and glibc 2.3.4 and above,
64-bit Linux Kernel 2.6.x and glibc 2.3.4 and above

Intel EMT64 processors
AMD64 processors
Mac OS X 10.4

PowerPC G4 and above, Intel
64-bit Sun Solaris 8, 9, 10

SPARC, ultraSPARC

These pictures correspond to the Q and U polarizations of the moon (not to scale) obtained with that routine

A little background on Matlab 2008a and the activation model. With 2008a Matlab has moved to an activation model, where you have to basically register your computer with The Math Works. With an individual license there are two choices you have: lock the license to a computer, or lock it to an individual. As I use Matlab at home, at work, and on my laptop I chose to lock it to myself.

Now Matlab 2008a came out in February 2008, and I'm just trying to install it now, which is all based on my fear of activation, since usually I am eager to download and install the latest version. So I bit the bullet yesterday and installed the OSX (laptop) and linux versions. Usually I get a nice CD package with installations for all platforms but that must have ended as well.

So this morning I figured that I would give installation a go. Usually a 5-10 minute affair, I spent 90+ minutes on this, and it still doesn't work on the linux box. Basically what would happen is that I would go through the automated steps (generate the file key, license file, download and give info where needed, rinse, repeat) and watch Matlab completely have a hissy fit that either my username didn't match, or my host ID didn't match or that I didn't have the desk pointed northeast (well, not that last one). I did my civic duty and dug around the troubleshooting site, where I found exactly three entries for activation problems. This must mean that I am completely unlucky to both have a problem and to have a non-standard problem that could not be fixed with answers #1-3.

At any rate, time is money right? So I figured I would give tech support a call. I got through on the second try, and actually go a human who was surprisingly helpful. The main problem on both machines was that the host ID generated was from the MAC address of the active internet connection, which is not what the license manager wants to see. So the laptop fix was an easy one after all, just use the MAC address of the primary connection, which was the wired connection (I was using the wireless at the time). In hindsight, yeah, that makes sense, but there's still too much voodoo involved for me.

The linux box was worse, where I do not have eth0 enabled since I have problems with it, and I use eth1 instead. So while to the operating system there is only eth1 (as far as I understand) the license file wants to communicate with eth0, which of course doesn't exist in the software space (now I may be way off on this, but this is what I could come up with for now). So my options are to either rename eth1 to eth0, or activate eth0. Well guess what, at this point I'm inclined to just not run Matlab 2008a since I don't really feel like risking the possibility of borking my internet connection just to get the latest version of Matlab running. So remind me again why I am paying those maintenance fees? Maybe I'm no activation super genius, but should it really be this difficult to get software that you've paid good money for to run? Sure, there's still an open thread with tech support but how much more time do I want to spend on this today? Well that's easy, none.

Now I may feel differently in a bit and try again. Or I may just drink more coffee and start installing Sage or Enthought and see how that goes. Or maybe I'll just try to get some work done.

Technorati Tags:
linux, Mac OS X, python, matlab


http://www.ele.uri.edu/~hansenj/projects/ele436/fft.pdf


Also, here they talk about the amplitudes, very useful:


http://www.dsprelated.com/groups/matlab/show/495.php


[sourcecode language='cpp']

for i = 1:size(images,3)
imshow(images(:,:,i));
title(['frame# ' num2str(i)]);
drawnow; %// this is why it works
end

[/sourcecode]

Sure, that's standard practice, but each year I have to stand up and justify to my boss why we need to pay these costs for our multiple Matlab users in our shop (a multi-user concurrent license is out of the question, don't even ask). So what's a user to do?

For years we've just bit the bullet and paid the fee, but with options such as R and Numpy/SciPy out there it may be time to loosen the chain a bit. Or maybe not.

A couple of possible alternatives to Matlab and their respective pros and cons:

R

R is a really nice statistical environment which has pretty much become the industry standard, replacing the very expensive S-Plus. It's easy to install, has an excellent GUI on OS X, and has a ton of community released packages which are usually made during the preparation of scientific papers. There are some downsides, as there can be multiple (sometimes possibly conflicting) packages (e.g. gam vs mgcv) but choice is good, right? The cons for me are that it's a new language to learn, and even though I write an m-script for everything, I find the scripting in R a bit clunky, even writing in TextWrangler and then hitting CTRL-R to have the SendToR script source the code for me. It's just something new, and while the built in functions are really nice, the learning curve for coding things is higher, and will it be faster in the long run than just using Matlab?

Numpy/SciPy

The Numpy/SciPy combo in Python is a viable alternative to Matlab, even having a page dedicated to showing you how easy it is to transition from Matlab. As with R, it's free, and there are a ton of functions available, but there is a downside for me. I've successfully installed it on CentOS 5.1 and OS X 10.5, but it was a bit complicated. I know that these are packaged in many distributions, but not in CentOS, and I had to install from either source or .egg files, which isn't all that tough, but took some time. I'm not writing the 24.3 steps I did to get it installed because honestly, I didn't write it down and I don't remember what I did. Next time I promise to list it out! On OS X I did it all through MacPorts on the MP version of python 2.5. Again, it took some massaging to get it all set up since I was using the non-default install of python.

Overall though, the reason for this little diatribe is that while there are alternatives to Matlab, they all involve learning new ways to do things which, after I successfully learn them, may not be faster than just doing it in Matlab. Most of the time I just need to get things done, and the $7/day cost of Matlab may be well worth it if I'm saving more than 10 minutes of time during that day (assuming for a minute that I am earning $42/hour).

I'm rambling a bit here, but these are just questions that I ask myself as I code things up at the desk. For each of these tools has their place, and in terms of maximum comfort and speed, I use each of them for their strengths. The main dilemma is that in a perfect situation I would drop the commercial Matlab for the free/open source alternatives, but at a minimal cost in dollars and time.

Technorati Tags:
linux, Mac OS X, programming, python, R, scientific programming

Download materi Grafik 2D

Download tugas takehome

Baca petunjuk dan kerjakan sebaik-baiknya. Kalau ada pertanyaan, lewat comment aja ya.

Selamat mengerjakan.

Download materi Grafik 3D

Selamat mengerjakan Tugas Rancang Anda. Semangat dan antusias kamu bisa!

God bless!

The most useful function in this code that I would like to mention is poly2mask. It is just an amazing function. What poly2mask would do is return you a binary image based on your region of interest and that region of interest is a polygon defined by set of points (vectors). In my case my polygon was a set of points connecting to form an Ellipse but if you understand the code then you can make any kind of rotating polygon using Matlab. Read the comments in the code and I guess you should be able to understand it. Here is the prototype of the function call. The code generates a sequence of bmp files which were later converted to an mpeg video using imagemagick.

function [x,y] = generateEllipse(h, k, a, b,imageSize)

where h,k,a,b are standard notation for an Ellipse and imageSize is the size of an nxn output frame in which the Ellipse is going to rotate. Make sure to choose a big enough size which can accommodate an Ellipse white rotating

To watch the outcome from the code, see these videos:

Note the point of rotation in both videos.

Point of rotation is the centre:

Point of rotation is the left corner:

Using this code you can choose any point as "Point of Rotation" but make sure the point you choose lies inside the Ellipse. The code takes "Point of Rotation" output through the mouse using the Matlab function ginput and here is the code:

function [x,y] = generateEllipse(h, k, a, b,imageSize) 

steps = 36;

%angle at which the Ellipse is initially located
atAngle = 0;

beta = atAngle / 180 * pi;
sinbeta = sin(beta);
cosbeta = cos(beta);

%we need to make a turn of 360 degrees to make a well formed Ellipse
i=1:360/steps:360;
alpha = i / 180 * pi;
sinalpha = sin(alpha);
cosalpha = cos(alpha);

%round function is important so as to store the points in the matrix
%the formula used is the parametric equation for Ellipse
x = round(h + (a * cosalpha * cosbeta - b * sinalpha * sinbeta)); 
y = round(k + (b * sinalpha * cosbeta + a * cosalpha * sinbeta));

%to connect with the line initial point so to make a connected Ellipse
x = [x,x(1)];
y = [y,y(1)];

bw = poly2mask(x,y,imageSize,imageSize);
imshow(bw);

 
%the user selects the point of rotation using the mouse

[rotationPointX rotationPointY] = ginput(1);
close

%translating the rotations points to origin

x1 = x-rotationPointX;
y1 = y-rotationPointY;

%the Ellipse will rotate ahead by 10 degree in each successive frame
rotationAngle = 10;

for index=0:299 %to generate 300 frames
    angle = mod(rotationAngle*index,360);
    %the equation for rotation

    newX = x1* cosd(angle) - y1*sind(angle); 
    newY = x1* sind(angle) + y1*cosd(angle);

    
    % return a binary image by masking the Ellipse region
    bw = poly2mask(newX+rotationPointX,newY+rotationPointY,imageSize,imageSize);
    figure
    imshow(bw);
    close

    fileName = sprintf('Ellipse1_frame_%s%04i.bmp', '', index)
    imwrite(bw,fileName);
end

The code was written in Matlab7.

Menemukan posisi matriks (vektor) dengan nilai tak nol

Ada vektor dengan nilai komponen seperti berikut,

>> X = [1 0 4 -3 0 0 0 8 6]

X =

1     0     4    -3     0     0     0     8     6
Nilai indeks ke 3 7 dan 1 ditentukan dengan perintah,

>> X([3 7 1])

ans =

4     0     1
variabel indices menunjukkan posisi (indeks) matriks X yang mempunyai nilai tak nol

>> indices = find(X)

indices =

1     3     4     8     9

posisi (indeks) matriks X dengan nilai lebih besar dari 2

>> find(X > 2)

ans =

3     8     9
posisi (indeks) matriks X dengan nilai sama dengan 0

>> find(X == 0)

ans =

2     5     6     7

Menampilkan nilai matriks X dengan nilai lebih besar dari 2

>> X(find(X > 2))

ans =

4     8     6

In the movie, John Leguzomo's character, a math teacher, is distracting his fellow panicking passenger in the Jeep with a mathematical question. The question he asks her is if he gave her a penny on Day 1 of the month, two pennies on Day 2 of the month, four pennies on Day 3 of the month, and so on, how much would money would she have after a month. She shouts $300 or some odd number like that. But, do you know that the amount is actually more than a 10 million dollars (Thanks to a student who mentioned that it was a penny that John offered on the first day, not a dollar - sometimes I do feel generous).

This question is based on a story from India and it goes as follows.

King Shriham of India wanted to reward his grand minister Ben for inventing the game of chess. When asked what reward he wanted, Ben asked for 1 grain of rice on the first square of the board, 2 on the second square of the board, 4 on the third square of the board, 8 on the fourth square of the board, and so on till all the 64 squares were covered. That is, he was doubling the number of grains on each successive square of the board. Although Ben’s request looked less than modest, King Shriham quickly found that the amount of rice that Ben was asking for was humongous.

QUESTIONS:

Write a MATLAB (you can use any other programming language) program for the following using the for or while loop.

1. Find out how many grains of rice Ben was asking for.
2. If the mass of a grain of rice is 2 mg, and the world production of rice in recent years has been approximately 600,000,000 tons (1 ton=1000 kg), how many times the modern world production was Ben's request?
3. Do the inverse problem - find out how many squares are covered if the the number of grains on the chess board are given to you. For example, how many squares will be covered if the number of grains on the chess board are 16?

This post is brought to you by Holistic Numerical Methods: Numerical Methods for the STEM undergraduate at http://numericalmethods.eng.usf.edu

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