solving a for loop error

Question

Hamzah Faraj 2020-4-22

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/519914-solving-a-for-loop-error

回答： Prasad Reddy 2020-4-22

Hello,

I want to generate set of temperatures (V)s with the function below, when I run the code it returns error as there is no index 0;

any help would be appreciated.

v0=0; % initial temperature
t0=0; % initial time
t= rand;
x=0:0.1:5;
n=length(x);

V(k)=V(k-1)+A(t(k)-sum(from 0 to k-1)t);

For example, V(1)=V(0)+A(t-t(0)) returns error as the index value is zero which is not possible.

V(2)=V(1)+A*(t(2)-(t(0)+t(1)));

t=zeros(1,n);
v=zeros(1,n);
for k=1:n
    t(k)= rand;
    V(k)=V(k-1)+A*(t(k)-sum(t(k)));
end

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Answer 1

Prasad Reddy 2020-4-22

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/519914-solving-a-for-loop-error#answer_427678

在 MATLAB Online 中打开

In MATLAB for a vector the index start from 'one'(1) not 'zero'(0).

supposeif you have a vector v=[2,4,6,3,9,7]

you can axcess thosevalues as v(1) and it will return 2,

v(2) will return 4

v(3) will return 6 and so on.

if you try to axcess v(0) it will return an error, because there is no such element with 'zero;(0) as index. so try to avoid the occurence of v(0) term in your loop.

I am re writing your program, i have understood the exact location of your problem but i havent got the value of A from your program, so i am taking A=4 an writing it.

clc
clear all
v0=0                       % initial temperature
t0=0                       % initial time
A=2
x=0:0.1:5
n=length(x)
t=x;
v=zeros(1,n);
v(1)=v0+A*(t(1)-t0)
for k=2:n
    v(k)=v(k-1)+A*(t(k)-t(k-1));
end