Drawing random lines in rectangular

Question

HyeongJu Lee 2021-11-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1591724-drawing-random-lines-in-rectangular

编辑： Image Analyst 2021-11-21

I so far coded to draw random lines in circumference.

However, I want to draw random lines.

It will be great if anyone can give me some tips.

Here is my code so far.

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

close all; clearvars; clc;
% SIMULATION DISK DIMENSIONS
xx0=0; yy0=0; % ceneter of disk
r=1; % disk radius
numbLines=30;
theta = zeros(numbLines,1);
theta(1) = 2*pi*rand();
for i = 2: numbLines 
    theta(i) =  2*pi*rand();
end
p=r*rand(numbLines,1);
q=sqrt(r.^2-p.^2);
sin_theta=sin(theta);
cos_theta=cos(theta);
xx1=xx0+p.*cos_theta+q.*sin_theta;
yy1=yy0+p.*sin_theta-q.*cos_theta;
xx2=xx0+p.*cos_theta-q.*sin_theta;
yy2=yy0+p.*sin_theta+q.*cos_theta;
%%% START Plotting %%%START
%draw circle
t=linspace(0,2*pi,300);
xp=xx0+r*cos(t); yp=yy0+r*sin(t);
plot(xp,yp,'k');
axis square; hold on;
axis tight;
xticks([]);yticks([]);
set(gca,'Visible','off');
%plot segments of Poisson line process
plot([xx1';xx2'],[yy1';yy2'],'b','LineWidth',2);
%%%END Plotting END%%%
slope = zeros(numbLines,1);
ycept = zeros(numbLines,1);
xx = [xx1'; xx2'];
yy = [yy1'; yy2'];
Total_length=[sqrt((xx1-xx2).^2+(yy1-yy2).^2)];
sumOfElements = sum(sum(Total_length));
Average_length = sumOfElements/numbLines
for ii = 1:numbLines
    slope(ii,1) = (yy(2,ii)-yy(1,ii))/(xx(2,ii)-xx(1,ii));
    ycept(ii,1) = -(yy(2,ii)-yy(1,ii))/(xx(2,ii)-xx(1,ii))*xx(1,ii)...
        +yy(1,ii); %% Might as well use xx(2,ii) & yy(2,ii) for the y-intercept
end
x_int = []; %% X and Y intersecting points
y_int = [];
for ii = 1:numbLines-1
    slope_temp = slope(ii,1); ycept_temp = ycept(ii,1);
    for jj = ii+1:numbLines
        xtemp = -(ycept(jj,1)-ycept_temp)/(slope(jj,1)-slope_temp);
        ytemp = slope_temp*xtemp+ycept_temp;
        rr_temp = xtemp^2+ytemp^2;
        if rr_temp<=r %% Pick only the intersecting points that are in the circle
            x_int = [x_int; xtemp];
            y_int = [y_int; ytemp];
        end
    end
end
scatter(x_int,y_int,100,'r','*');
n = numel(x_int);
Mean_fiber_segment_length = sumOfElements / (numbLines+2*n)
Network_density = sumOfElements
Crosslink_number = numel(x_int)

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Image Analyst 2021-11-21

编辑：Image Analyst 2021-11-21

test8.m

Just to show the missing image of what his code produces:

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Answer 1

Sulaymon Eshkabilov 2021-11-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1591724-drawing-random-lines-in-rectangular#answer_836519

Some of the loops can be substituted with vectorization operations, i.e.:

...
numbLines=30;
theta = 2*pi*rand(numbLines, 1);   
...
%%% START Plotting %%%START
...
slope(:,1) = (yy(2,:)-yy(1,:))./(xx(2,:)-xx(1,:));
ycept(:,1) = -(yy(2,:)-yy(1,:))./(xx(2,:)-xx(1,:)).*xx(1,:)+yy(1,:); %% Might as well use xx(2,ii) & yy(2,ii) for the y-intercept
...