fonction modelisant une structure HPP

debutant en informatique on nous a demandé de comprendre la fonction suivante, je n'ai jamais fait de MATLAB, qqn serait il capable de me donner une traduction en francais de l'essentiel du programme?
notre objectif est de modifier le programme pour modeliser un autre type d'ecoulement dans le cadre d'un projet en mecanique. Nous avons besoin de comprendre les fonctions principales utilisees .
merci

Code:

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function [x1,x2,x3,x4,x5,x6,x7]=collision(x1,x2,x3,x4,x5,x6,x7,N)
  for i=1:N
    for j=1:N
      c = x1(i,j)+2*x2(i,j)+4*x3(i,j)+8*x4(i,j)+16*x5(i,j)+32*x6(i,j)+64*x7(i,j);
      r = rand<0.5;
      switch c
      case 5
        x1(i,j) = 0; x2(i,j) = 1; x3(i,j) = 0; x7(i,j) = 1;
      case 9
        x1(i,j) = 0; x2(i,j) = r; x3(i,j) = 1-r; x4(i,j) = 0; x5(i,j) = r;
        x6(i,j) = 1-r;
      case 10
        x2(i,j) = 0; x4(i,j) = 0; x3(i,j) = 1; x7(i,j) = 1;
      case 17
        x1(i,j) = 0; x5(i,j) = 0; x6(i,j) = 1; x7(i,j) = 1;
      case 18
        x1(i,j) = r; x2(i,j) = 0; x3(i,j) = 1-r; x4(i,j) = r; x5(i,j) = 0;
        x6(i,j) = 1-r;
      case 20
        x3(i,j) = 0; x4(i,j) = 1; x5(i,j) = 0; x7(i,j) = 1;
      case 21
        x1(i,j) = 0; x2(i,j) = 1; x3(i,j) = 0; x4(i,j) = 1; x5(i,j) = 0;
        x6(i,j) = 1;
      case 34
        x1(i,j) = 1; x2(i,j) = 0; x6(i,j) = 0; x7(i,j) = 1;
      case 36
        x1(i,j) = r; x2(i,j) = 1-r; x3(i,j) = 0; x4(i,j) = r; x5(i,j) = 1-r;
        x6(i,j) = 0;
      case 40
        x4(i,j) = 0; x5(i,j) = 1; x6(i,j) = 0; x7(i,j) = 1;
      case 42
        x1(i,j) = 1; x2(i,j) = 0; x3(i,j) = 1; x4(i,j) = 0; x5(i,j) = 1;
        x6(i,j) = 0;
      case 65
        x1(i,j) = 0; x2(i,j) = 1; x6(i,j) = 1; x7(i,j) = 0;
      case 66
        x1(i,j) = 1; x2(i,j) = 0; x3(i,j) = 1; x7(i,j) = 0;
      case 68
        x2(i,j) = 1; x3(i,j) = 0; x4(i,j) = 1; x7(i,j) = 0;
      case 72
        x3(i,j) = 1; x4(i,j) = 0; x5(i,j) = 1; x7(i,j) = 0;
      case 73
        x1(i,j) = 0; x2(i,j) = r; x3(i,j) = 1-r; x4(i,j) = 0; x5(i,j) = r;
        x6(i,j) = 1-r;
      case 80
        x4(i,j) = 1; x5(i,j) = 0; x6(i,j) = 1; x7(i,j) = 0;
      case 82
        x1(i,j) = r; x2(i,j) = 0; x3(i,j) = 1-r; x4(i,j) = r; x5(i,j) = 0;
        x6(i,j) = 1-r;
      case 85
        x1(i,j) = 0; x2(i,j) = 1; x3(i,j) = 0; x4(i,j) = 1; x5(i,j) = 0;
        x6(i,j) = 1;
      case 96
        x1(i,j) = 1; x5(i,j) = 1; x6(i,j) = 0; x7(i,j) = 0;
      case 100
        x1(i,j) = r; x2(i,j) = 1-r; x3(i,j) = 0; x4(i,j) = r; x5(i,j) = 1-r;
        x6(i,j) = 0;
      case 106
        x1(i,j) = 1; x2(i,j) = 0; x3(i,j) = 1; x4(i,j) = 0; x5(i,j) = 1;
        x6(i,j)= 0;
      end
    end
  end
end

Et le fichier principal :

Code:

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% FHP-2
 
% The domain is NxN, hexagonal
N              = 200 ;
% domain with high density, disc of radius r
r = 8;
% Initial density of cells alive
initialDensity = 0.01;
highDensity =0.6;
% Number of iteration steps
nSteps         = 100;
 
% Create a random initial condition
cells1 = rand(N,N)<initialDensity;
cells2 = rand(N,N)<initialDensity;
cells3 = rand(N,N)<initialDensity;
cells4 = rand(N,N)<initialDensity;
cells5 = rand(N,N)<initialDensity;
cells6 = rand(N,N)<initialDensity;
cells7 = rand(N,N)<initialDensity;
 
% Higher density inside a disc as initial condition
for i=1:N
  for j=1:N
    if (mod(j,2)==1)
      if((i-N/2+(j-1)/2)^2+(j-N/2)^2 < r^2)
        cells1(i,j)=rand<highDensity;
        cells2(i,j)=rand<highDensity;
        cells3(i,j)=rand<highDensity;
        cells4(i,j)=rand<highDensity;
        cells5(i,j)=rand<highDensity;
        cells6(i,j)=rand<highDensity;
        cells7(i,j)=rand<highDensity;
      elseif((i-3*N/2+(j-1)/2)^2+(j-N/2)^2 < r^2)
        cells1(i,j)=rand<highDensity;
        cells2(i,j)=rand<highDensity;
        cells3(i,j)=rand<highDensity;
        cells4(i,j)=rand<highDensity;
        cells5(i,j)=rand<highDensity;
        cells6(i,j)=rand<highDensity;
        cells7(i,j)=rand<highDensity;
      end
    else
      if((i-N/2+j/2)^2+(j-N/2)^2 < r^2)
        cells1(i,j)=rand<highDensity;
        cells2(i,j)=rand<highDensity;
        cells3(i,j)=rand<highDensity;
        cells4(i,j)=rand<highDensity;
        cells5(i,j)=rand<highDensity;
        cells6(i,j)=rand<highDensity;
        cells7(i,j)=rand<highDensity;
      elseif((i-3*N/2+j/2)^2+(j-N/2)^2 < r^2)
        cells1(i,j)=rand<highDensity;
        cells2(i,j)=rand<highDensity;
        cells3(i,j)=rand<highDensity;
        cells4(i,j)=rand<highDensity;
        cells5(i,j)=rand<highDensity;
        cells6(i,j)=rand<highDensity;
        cells7(i,j)=rand<highDensity;
      end
    end
  end
end
 
aviobj = avifile('FHP2.avi','fps',15); 
 
plot_cells = cells1(:,:,:)+cells2(:,:,:)+cells3(:,:,:)+cells4(:,:,:)+ ...
                 cells5(:,:,:)+cells6(:,:,:)+cells7(:,:,:)>0;
 
 
 
    % Plot the result
    imagesc(zeros(N,N));
    hold on
    for im=1:N
      if (mod(im,2)==1)
        imagesc(0.5:N-0.5,im,circshift(plot_cells(1:N,im),[(im-1)/2,0])');
       colormap(gray)
 
      else
        imagesc(1:N,im,circshift(plot_cells(1:N,im),[im/2-1,0])');
        colormap(gray)
      end
    end
 
% Main time loop
for i=1:nSteps
    % Propagation
    cells1 = circshift(cells1,[1,0]);
    cells2 = circshift(cells2,[1,-1]);
    cells3 = circshift(cells3,[0,-1]);
    cells4 = circshift(cells4,[-1,0]);
    cells5 = circshift(cells5,[-1,1]);
    cells6 = circshift(cells6,[0,1]);
 frame = getframe(gcf);
    aviobj = addframe(aviobj,frame);
    % Collision
    [cells1,cells2,cells3,cells4,cells5,cells6,cells7] = ...
      collision(cells1,cells2,cells3,cells4,cells5,cells6,cells7,N);
    % Field to be plotted
    plot_cells = cells1(:,:,:)+cells2(:,:,:)+cells3(:,:,:)+cells4(:,:,:)+ ...
                 cells5(:,:,:)+cells6(:,:,:)+cells7(:,:,:)>0;
 
 
 
    % Plot the result
    imagesc(zeros(N,N));
    hold on
    for im=1:N
      if (mod(im,2)==1)
        imagesc(0.5:N-0.5,im,circshift(plot_cells(1:N,im),[(im-1)/2,0])');
        colormap(gray)
    else
        imagesc(1:N,im,circshift(plot_cells(1:N,im),[im/2-1,0])');
        colormap(gray)
 
      end
    end
    drawnow;
 
    hold off
end
 
 
aviobj = close(aviobj);

C'est bizarre que l'on te demande cela d'entrée avec un programme complexe...?? Mais déjà, à quoi il sert ton programme...? Tu as des variables d'entrée, de sorties, tu doit savoir à quoi elles correspondent, est-ce des matrices...??

Salut,

Si tu ne connais pas MATLAB, tu trouveras sur le forum une faq et des tutoriels pour commencer (voir dans les liens de ma signature). Je pense que la première étape pour toi, c'es d'apprendre les bases de MATLAB (indépendamment du programme que l'on t'a donné).

Ensuite tu pourras passer à la compréhension de ton programme. Tu peux commencer par exécuter ton programme, voir ce que tu obtiens, comment sont remplis les variables, etc... Tu pourras t'aider de l'aide de MATLAB qui est très bien faite, par exemple, dans la ligne :

Code:

cells1 = rand(N,N)<initialDensity;

tu peux regarder l'aide de la fonction rand :

Code:

help rand

Et pour les parties que tu n'arrives vraiment pas à comprendre, tu peux poser des questions sur le forum.