Decrease time in plotting the graph

      % This code is to make a sparse matrix of the roof, from where the light can come
    % in the receiver (Rx). This code would work for receiver at any position, orientation, field of view, etc.

    clear;clc;
    t0 = tic;
    % ----------------Dimensions of the room------------------------------------------
    length = 10.0;            % Length of Room [m]
    breadth = 10.0;            % Breadth of Room [m]
    height = 5.0;               % height of Room [m]
    % ---------------------------------------------------------------------------------

    % -----------------Characteristics of Transmitter/Source - LED--------------------

    n = 4;                              % Number of LEDs is given by 
    LED_VA = 60.0;             % <Find out what is it called> ????
    Ntx = [0 0 -1];            % Normal to the Tx's plane (Orientation)
    % Let the position of Tx be Pos_Tx
    i=0; j=0; k=5;
    Pos_Tx = [i j k];
    % ---------------------------------------------------------------------------------

    % ----------------Characteristics of Receiver - Photodiode-------------------------

    Rtx = [0 0 1];            % Normal to the Rx's plane (Orientation)
    Rx_FOV = 36.0;            % FOV (field of view)
    psi_c = (Rx_FOV*pi)/180;      % FOV (field of view) in Radians
    % Let the position of Rx be Pos_Rx
    Pos_Rx = [5 5 0];
    % ---------------------------------------------------------------------------------

    space = 0.5;
    LOS = zeros(max(size(0:space:length)), max(size(0:space:breadth)));

    toc(t0)
    hold on;
    t1 = tic;
    r=1;s=1;

    for i=0:space:length
        r=1;
      for j=0:space:breadth

        Pos_Tx = [i j k];    
      
    % ---------------------------------------------------------------------------------
    DD_Tx_Rx = Pos_Rx - Pos_Tx;  % Direction from Tx to Rx
    DD_Rx_Tx =   -1*DD_Tx_Rx;    % Direction from Rx to Tx

    % Distance between Tx and Rx
    R = sqrt((Pos_Tx(1,1) - Pos_Rx(1,1)).^2 +(Pos_Tx(1,2) - Pos_Rx(1,2)).^2 +(Pos_Tx(1,3) - Pos_Rx(1,3)).^2);
              
    % Angle between orientation of Tx and direction of Rx
    Phi = acosd( dot(DD_Tx_Rx,Ntx)./(R.*(sqrt((Ntx(1,1)^2 + Ntx(1,2)^2 + Ntx(1,3)^2)))));

    % Angle between orientation of Rx and direction of Tx
    Psi = acosd( dot(DD_Rx_Tx,Rtx)./(R.*(sqrt((Rtx(1,1)^2 + Rtx(1,2)^2 + Rtx(1,3)^2)))));

    phi = (Phi*pi)/180;          % Angle of irradiance (phi) in Radians
    psi = (Psi*pi)/180;          % Angle of incidence (psi) in Radians
    % ---------------------------------------------------------------------------------

    % ----------------- For Direct Light ----------------------------------------------
    % LOS (line of sight) propagation path channel transfer function - HLOS
    if (psi>=0) && (psi<=psi_c) && (Phi<=LED_VA) 
        HLOS = 1.0;
    elseif (psi>psi_c)
        HLOS = 0.0;
    elseif (Phi>LED_VA)
        HLOS = 0.0;
    elseif (Psi>Rx_FOV)||(Phi>Rx_FOV)
        HLOS = 0.0;
    end;

    LOS(r,s) = HLOS;
    % ---------------------------------------------------------------------------------
            plot3(i,j,LOS(r,s),'.b');

    r = r+1;
    end;
    s = s+1;
    end;
    grid on;
    toc(t1)

Nothing much to understand in this code.

The main thing is that plot3 function is taking 75% (almost 2.5 sec.) of all time. Is there a better way to plot the function in much less time than that?

Any other idea for optimizing the code is welcome... Please help out. Thanks Nishant

Answer 1

[Daniel Shub]

You are calling plot3 in your loops. You would probably be better off saving all the data and calling plo3 once.