update all array of the value

Question

vaya putra 2022-6-18

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1743125-update-all-array-of-the-value

回答： Image Analyst 2022-6-18

采纳的回答： Image Analyst

i have array 10000x1

my plan is to upadate all value into new value

a=old; %10000x1

b=new; % 10000x1

by using a=b;

i got problem for next calculation looks the new value duplicate many time then i got divergence calculation

i tried changed some value

example;

b(10)=10e-9;

b(11)=10e-9;

b(12)=10e-9;

b(13)=10e-9;

the calculation worked properly and the calculation did not multiple the new value

but i must update all value any idea

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Voss 2022-6-18

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@vaya putra: Not that this necessarily addresses your question, but note that 10e-9 means 10*10^-9, which is 10^-8 (i.e., 1e-8):

10e-9
ans = 1.0000e-08

vaya putra 2022-6-18

编辑：vaya putra 2022-6-18

i tried to changed in the particulary address i got the same problem in my calculation

a(3000) = b(3000)

...

a(8000) = b(8000)

but when change one by one with real number

a(3000)=9e-14;

a(3001)=9e-14;

....,...a(8000)=9e-14;

it worked

i dont know what the problem with my calculation

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Answer 1

Image Analyst 2022-6-18

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1743125-update-all-array-of-the-value#answer_988330

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When you do

a=old; %10000x1
b=new; % 10000x1
a=b;

a will now have the values of b and new. Then you said the problem is when you try to change a few specific values by doing:

b(10)=10e-9;
b(11)=10e-9;
b(12)=10e-9;
b(13)=10e-9;

Now this will change elements 10-13 of b but will NOT change those elements in new or a. Just because you did a=b does not mean that a is a pointer into the b locations of memory and that changing b should automatically change a simultaneously. If you want a to change you'll have to assign those elements of a explicitly.