Implement double summation in Matlab

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Jean Pazos
Jean Pazos 2020-12-14
评论： Image Analyst 2023-5-27
Hi.
Could you help me implement these two equations in Matlab utilizing for loops?
SF is a matrix of 1400 rows and 120 columns.
N=120
t=1:1400
I think the first equation can be implemented with cumsum(SF,2) but I'm curious as to how it'd be with foor loops.
Thanks

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回答（2 个）

Rik
Rik 2020-12-14
编辑：Rik 2020-12-14
The sigma symbol contains all syntactic elements that you need for a for loop:
y=0;%initialize to 0
for j=1:N
for i=1:j
y=y+f(i);
end
end
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Jean Pazos
Jean Pazos 2020-12-14
Yes, I wanted to understand how to implement summation with for loops.I think I've gotten the gist.
As for the equations in my OP. The first one is implemented with y=cumsum(SF,2), right?
How can I implement the product equation with functions and loops if necessary? I'm a little lost
Rik
Rik 2020-12-14
编辑：Rik 2020-12-14
Maybe cumprod is what you're looking for there? If you think about what should happen mathematically, that operator mean to take the product of all elements, right? That would make it analogous to the sigma operator, which uses + on all operators. Note that while 0 is the null operand for sum (or is it called unit operand?), for a product that operand is 1.

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aisha chauhan
aisha chauhan 2023-5-27
编辑：Image Analyst 2023-5-27
Please convert this equation into MATLAB code:
  1 个评论
Image Analyst
Image Analyst 2023-5-27
Try a nested for loop:
theSum = 0;
for ii = 1 : Ncl
for ell = 1 : Nray
aHt = at(phi(ii, ell)^t, theta(ii, ell)^t)
theSum = theSum + alpha(ii, ell) * ar(phi(ii, ell)^r, theta(ii, ell)^r) * aHt^H
end
end
H = gamma * theSum;
But the equation seems weird, or maybe the nomenclature was just not explained. Like why are you raising a sub t to the H power when H is the result of the loop? To learn other fundamental concepts, invest 2 hours of your time here:
MATLAB Academy - Free 2 hour training
If you still have trouble, start your own question instead of posting in some 3 year old thread of @Jean Pazos's.

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