Nested for loop problem

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JDilla 2015-3-12

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/182721-nested-for-loop-problem

编辑： Guillaume 2015-3-12

I am modelling seismic rays, (I am very new to Matlab, this is my first attempt at solving a problem), and I have to plot a series of seismic rays at various angles (any number I choose up to 20 degrees) that penetrate through 5 layers, and reflect at the boundary of the 4th and 5th layer. Through each layer, the seismic ray needs to refract. I have managed to achieve this with the code below.

HOWEVER, I need to plot a SERIES of rays, I have only managed one. I wanted a ray to propagate at 1 degree, increments of 5 degrees up to i=20 (the initial angle you see plotted). I want to use a nested for loop to achieve this, but I'm not sure where i'm going. Ultimately, I'm trying to achieve a single plot of several seismic rays with their reflections such as below, at various angles, with the maximum angle being 20.

A plot similar to this picture is what I'm trying to achieve; multiple rays and their reflections. The code for the reflections is

reflectionx=h(end); 
plot(2*reflectionx-h,depth) 
axis ij

%COMPUTE DISTANCE TRAVELLED BY THE RAY IN EACH LAYER  
clear  
%DEFINE VARIABLES  
z1 = 0;                      %Depth at y=0   
v = [3:7];                   %Velocities at each subsequent layer  
i = 20;                      %Takeoff Angle in degrees  
%COMPUTE DIAGONAL DISTANCE BY THE RAY IN EACH LAYER  
 for j = 1:5:i
for n = 1:5;                        %n = number of layers      
    v = v(n);
    i;  
    d=z1/cosd(i);                   %calculate diagonal distance
    h(n)=z1*sind(i)                 %calculate horizontal distance
    t(n) = d/v;
    v = [3:7];
    depth(n)=z1
    sini = ((sind(i)*(v+1))/v);
    i= asind(sini)
    z1=z1+2;               
    end
 end
HorizontalDistance=[cumsum(h)];
disp(HorizontalDistance);  
plot(h,depth)                  %Plot horizontal distance vs depth  
hold on  
reflectionx=h(end);  
plot(2*reflectionx-h,depth)    %Plot reflected ray   
axis ij                        %Places origin at upper left corner of plot