Summation in MATLAB in 4 dimenstion

I have a matrix with 4 dimentions.

I should sum values.

w(i,j,k,t)

k is constant.t is time

My problem is how to add t to loap.

for example for t=1, give me the results but I repeate up to 12. I need sumation for each t seprately and save it and then repeat it for 12 times.

How can do it?

sum=0
for i=1:i
    for  j=97:176
        if w(i,j,15,t)<0
            sum=sum+w(i,j,15,t)/(pm(i,j)*pn(i,j))
        end
    end
end

[Walter Roberson]

We advise against using sum as the name of a variable. It is very common for people who use sum as a variable name to find that they also need to call upon the MATLAB sum function. And besides, it confuses the readers.

Answer 1

[Torsten]

for t = 1:T
  s(t) = 0;
  for i=1:i  <---- for i=1:i does not make sense
    for j=97:176
        if w(i,j,15,t)<0
            s(t)=s(t)+w(i,j,15,t)/(pm(i,j)*pn(i,j))
        end
    end
  end
end 

[JAVAD]

Thanks

It works!

Answer 2

[Fangjun Jiang]

S = sum(X,DIM) sums along the dimension DIM

[JAVAD]

Thanks for your response.

I use it before but I think that in my case it doesnot work. If you think work, can you rewrite my codes to understand it better.

[Fangjun Jiang]

You need to clarify

1. what is "i" in "for i=1:i"
2. assume t is 1:12?
3. pm? pn?