How to avoid a loop using vectors?

Question

Yuval 2013-11-9

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/105441-how-to-avoid-a-loop-using-vectors

编辑： Azzi Abdelmalek 2013-11-9

Hi, Is there a way to avoid using a for loop (or any loop for that matter) in the following?:

h=(10^-1).^[1:8];
x=pi;
r=5e-6.*rand(16,1);
for i=1:8
    fminush(i)=cos(x-h(i))+r(i);
    fplush(i)=cos(x+h(i))+r(i+8);
end
fder=(fplush-fminush)./(2*h);
plot(log(h),log(abs(-sin(x)-fder)))

I have tried redefining r to be of size 8 then adding it to both fminush and fplush, to no avail. Matlab would still alert for "matrix dimensions must agree". I'd be thankful for some advice.

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Answer 1

Azzi Abdelmalek 2013-11-9

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/105441-how-to-avoid-a-loop-using-vectors#answer_114647

编辑：Azzi Abdelmalek 2013-11-9

在 MATLAB Online 中打开

h=(10^-1).^[1:8];
x=pi;
r=5e-6.*rand(1,16);
fminush1=cos(x-h)+r(1:8);
fplush1=cos(x+h)+r(9:16)
fder=(fplush-fminush)./(2*h);
plot(log(h),log(abs(-sin(x)-fder)),'r')