for loop - how to obtain a list of solutions

Question

Sergio Orasch 2020-9-9

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/591352-for-loop-how-to-obtain-a-list-of-solutions

回答： Walter Roberson 2020-9-9

hello,

I would like to show you my problem in MATLAB. In order to solve an equation with an variable input, I created a for loop in order to obtain a list with all solutions. The for loop should run n times. Everytime it starts s0_y should be changed (add +100 to the current value). The output v_safe should be safed in a seperate list for further calculations. How do I run the loop n times? How do I increase s0_y by 100? How do I save v_safe in a seperate list? Thank you very much for any support.

If I run the program I get following error code.

Index exceeds the number of array elements (1).

s0_y = y_k(k)

Command Window results:

n = 7

s0_y = 1000

s0_y = 1100

s0_y = 1300

s0_y = 1600

code:

v0_x = 100; %m/s
s0_x = -5000; %m 
a_x = 0; %m/s^2
syms v0_y; 
s0_y = 1000; 
a_y = 0; %m/s^2
h_B = 1500; %m 
S_H = 100; %m 
h_BS = h_B+S_H; 
n = length(s0_y:100:h_BS)
    
for k = 1:n
    y_k = [s0_y:100:h_BS];
    s0_y = y_k(k)
    s0_y
syms t;
s_x = s0_x+v0_x*t+(a_x*t*t)/2 == 0;
t_col = solve(s_x,t);
s_sol = s0_y+v0_y*t_col+(a_y*t_col*t_col)/2-h_BS;
v_safe = solve(s_sol,v0_y);
end

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Answer 1

Walter Roberson 2020-9-9

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/591352-for-loop-how-to-obtain-a-list-of-solutions#answer_492298

在 MATLAB Online 中打开

y_k = [s0_y:100:h_BS];
for k = 1:n
    s0_y = y_k(k)
    s0_y
    syms t;
    s_x = s0_x+v0_x*t+(a_x*t*t)/2 == 0;
    t_col = solve(s_x,t);
    s_sol = s0_y+v0_y*t_col+(a_y*t_col*t_col)/2-h_BS;
    v_safe(k) = solve(s_sol,v0_y);
end