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

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thebasher
thebasher 2014-1-31
评论： thebasher 2014-1-31
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
Amit 2014-1-31
编辑：Amit 2014-1-31
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
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
thebasher 2014-1-31
Excellent and informative replies. Thank you for your time. It is much appreciated.

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