How can I nest two loops of different dimension without using a for loop?

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thebasher 2014-1-31

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https://ww2.mathworks.cn/matlabcentral/answers/114312-how-can-i-nest-two-loops-of-different-dimension-without-using-a-for-loop

评论： thebasher 2014-1-31

采纳的回答： Amit

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Hi,

As the title says, I'm trying to nest two loops without using for loops, since they really delay the computation time.

For example:

I want n to vary from 1 to 365 (for each day of the year). Within that loop, I want h to vary from 11 to -12 (24 values for 24 hours) for each day.

n=1:365
    delta=sind(360.*n)
    h=11:-1:-12
    i=1:length(h); %For indexing, because I can't index negative values
    theta=cosd(delta).*sind(15.*h)
    a=cosd(theta)
    b=cosd(phi)./2
    c=cosd(phi)./2
    z(i)=a+b+c
%Increase n, repeat loop and add result to z each time
%Plot sum of loop return 
figure(1)
plot(z)

I hope I was clear with my question. I would like the calculations done for one hour, put into z, done for the second hour, added to z, etc etc for the whole day (24 hours). Then, once the day completed, I want n to increase and redo the 24 hours. I want n to finish after 365 days.

I appreciate your time and input.

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Amit 2014-1-31

编辑：Amit 2014-1-31

where is n or h coming in calculation here?

thebasher 2014-1-31

Sorry, I was trying to simplify all my equations. I will edit the original code to make it more clear.

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采纳的回答

Amit 2014-1-31

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/114312-how-can-i-nest-two-loops-of-different-dimension-without-using-a-for-loop#answer_122773

编辑：Amit 2014-1-31

在 MATLAB Online 中打开

phi = 0.1; % Undefined
n = 1:365;
delta = sind(360*n);
h = 11:-1:-12;
a= cos(bsxfun(@times,cosd(delta),sind(15*h)'));
b=cosd(phi)./2;
c=cosd(phi)./2;
z = a+b+c; % in z: 24 x 365 matrix

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Amit 2014-1-31

That is correct.

Z has 24 rows and 365 columns. Lets pick column 1 in z, then rows 1 to 24 in column represents values for z corresponding to n = 1 and h from 11 to -12 (all 24 values)

thebasher 2014-1-31