Save value from overwriting in while loop
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end
In this while loop I want to save u(end) and u1(end) in a vector but when i Try to do it it becomes problematic. Firslty I know how to do it if it only would been one variable (u), but in m case it is u1 too. For every iteration u1 and u ( last element of those ) gets overwritten so I dont know how to save u and u1 ( last elements) in a vector.
2 个评论
Ameer Hamza
2020-5-8
Mohammed Hassan, This forum is for public benefit. Deleting the code in question makes the question meaningless for anyone else. I am restoring the code so that anyone else coming to this form can have a better idea about the original question.
Ameer Hamza
2020-5-8
Text of original Question:
hI
En=50
While d >tollerance
[g u] = main(En,k)
En=En*3;
[g u1] = main(En,k)
d=abs((u(En/3)+1)-u1(En+1));
end
In this while loop I want to save u(end) and u1(end) in a vector but when i Try to do it it becomes problematic. Firslty I know how to do it if it only would been one variable (u), but in m case it is u1 too. For every iteration u1 and u ( last element of those ) gets overwritten so I dont know how to save u and u1 ( last elements) in a vector.
回答（1 个）
Ameer Hamza
2020-5-7
编辑：Ameer Hamza
2020-5-7
The most simplest way is to let the array grow dynamically
En=50
u = [];
u1 = [];
while d >tollerance
[g u(end+1)] = main(En,k)
En=En*3;
[g u1(end+1)] = main(En,k)
d=abs((u(En/3)+1)-u1(En+1));
end
For an efficient solution. See this FEX submission from John: https://www.mathworks.com/matlabcentral/answers/510713-is-it-possible-to-store-the-intermediate-values-of-fmincon
13 个评论
mohamed hassan
2020-5-7
Ameer Hamza
2020-5-7
Are the outputs of main(En,k) scalar or a vector?
mohamed hassan
2020-5-7
Ameer Hamza
2020-5-7
Ok, you can do something like this.
En=50
u = [];
while d >tollerance
[g temp] = main(En,k)
u(end+1) = temp(end);
En=En*3;
[g temp] = main(En,k)
u(end+1) = temp(end);
d=abs((u(En/3)+1)-u1(En+1));
end
Note that it create vector u such that odd elements u(1), u(3), u(5) contain value from first main() and even elelemts contain values from second main()
mohamed hassan
2020-5-7
mohamed hassan
2020-5-7
Ameer Hamza
2020-5-7
You mentioned before "Also, I want the values to be in the same vector where the first value will be u and the second u1 and the third u and the fourth u1 so and so on". So my code create one vector u and save all elements in it.
"do I need to define temp before". No. temp is output variable. You don't need to define it before.
"do I need to disp u in the end". yes, If you want to see the value of u in the command window, then use disp(u)
Ameer Hamza
2020-5-7
编辑：Ameer Hamza
2020-5-7
Oh! I missed that u1. Are you trying to subtract the value of u and u1 (from your code) in each loop. If yes, then try this
En=50
u = [];
while d >tollerance
[g temp1] = main(En,k)
u(end+1) = temp1(end);
En=En*3;
[g temp2] = main(En,k)
u(end+1) = temp2(end);
d=abs(temp1-temp2);
end
mohamed hassan
2020-5-7
Ameer Hamza
2020-5-7
I missed the to assign last elements of temp1 and temp2. Now try the updated code in my last comment. I think it should do what you want.
mohamed hassan
2020-5-7
Ameer Hamza
2020-5-7
'temp1(end)' means that the last element of the vector temp1. Since you mentioned that main() returns a vector, and you want to keep the last value of that vector. The 'temp1(end)' keeps that last value.
u(end+1) tells the MATLAB to extend the array 'u' and add the new element to the extended location. This makes sure that the last value is not overwritten.
mohamed hassan
2020-5-7
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