I have a vector and want to compute the average value

Question

reem 2011-6-4

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/8777-i-have-a-vector-and-want-to-compute-the-average-value

[EDIT: 20110604 17:36 CDT - reformat - WDR]

Good afternoon,

This is my program and teacher Matt helped me but the result of my program should appear like the result of the main program This is my program but my graph result is different from the main program because the mean value must be zero or near to zero

Please, anyone help me

The Main program and I want my graph result appear like the graph result of main program

k=-1;
for n=1:400
    k=k+1;
    x(k+1)=k*(-2*pi/400);
end
x=x(:)';
s=ones(1,301);
z=0;  
for j=1:400
    z=z+1;
    y(z,:)=5*cos(2*pi*100*(0:1/300:1)+x(1,z).*s(1,:));
end
r=0;
for i=1:301
    r=r+1;
    mean(r)=sum(y(:,i))/400;
end
plot(mean,'o'),grid
title('The Mean of the signal')
ylabel('Mean')
xlabel('Number of points')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

My program

theta = linspace(-2*pi,2*pi,400);  % 400 equally spaced points 
t = linspace(0,1,301);  % 301 equally spaced points between 0 and 1.
w = 2*pi*100;
A = 5;
X = A*cos(bsxfun(@plus,theta.',w*t));
r=0;
for i=1:301
    r=r+1;
    mean(r)=sum(X(:,i))/400;
end
plot(mean,'o'),grid
title('The Mean of the signal')
ylabel('Mean')
xlabel('Number of points')

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reem 2011-6-4

Thanks a lot jan

but I do not have any problem in my program,I put two programs here,the first program is ((Main program))it and t((my program))it is the second program,and these two programs have the same ideas and the result of the graph must be appear similar,so my question is why my program result not appear like the result of the first program((main program)).

Jan 2011-6-4

@Reem: It would be polite to make the reading of your question as easy as possible.

It is obvious that the two versions calculate different numbers. But due to the strange formatted code, the comparison of the two programs is difficult. If you concentrate to the essential lines, we could see both versions without scrolling and the difference would be *much* easier to see - and therefore to find.

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Answer 1

Matt Fig 2011-6-4

2
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/8777-i-have-a-vector-and-want-to-compute-the-average-value#answer_12105

在 MATLAB Online 中打开

First of all, don't name a variable mean! This will mess up your use of the MATLAB function MEAN. This produces a plot similar to your main program, but there will be slight differences due to different approaches.

clear mean % Get rid of this bad variable name!!
theta = linspace(-2*pi*399/400,0,400); % 400 equally spaced points
t = linspace(0,1,301); % 301 equally spaced points between 0 and 1.
w = 2*pi*100;
A = 5;
X = A*cos(bsxfun(@plus,theta.',w*t));
mn2(r) = mean(X);  % No need for a loop, use the MATLAB function
figure
plot(mn2,'o'),grid
title('The Mean of the signal')
ylabel('Mean')
xlabel('Number of points')