Defining a variable in specific nodes

Hi,

I need to define a variable B(j)) in the 1/2 3/2 5/2.... . e.g i have the variables A(i) and B(j). So the loops are( for i =2:N and j=2:N) .

And B(j)=A(i+1)-A(i)

[Adam Danz]

" I need to define a variable B(j)) in the 1/2 3/2 5/2.... "

I don't understand.

Try to explain again.

[m m]

I am trying to calculate the potentiel A(i), after that i want to calculate the electric field B(j) whitch related with the potentiel by :

B(j)=(A(i+1)-A(i) )/dx.

Knowing that j=i+12

So if i use this relation B(j)=(A(i+1)-A(i) )/dx. How can i inmplement this in matlab??

[Adam Danz]

"I am trying to calculate the potentiel A(i)"

I don't know what this means.

"after that i want to calculate the electric field B(j) whitch related with the potentiel by : B(j)=(A(i+1)-A(i) )/dx Knowing that j=i+12"

Something along these lines, perhaps?

for i = __ : __ % ???  
    for j = 1:12
        B(j) = (A(i+1)-A(i) )/dx
    end
end

This can probably be written without for-loops but the concept is still unclear to me.

[m m]

N=10;

for i = 2 : N-1%

for j = ___:___ ??

B(j) = (A(i+1)-A(i) )/dx

end

end

the loop for j starts from what in this case?

[Adam Danz]

Then the j-loop might be

for j = i:i=12

end

Im basing this off of your info "Knowing that j=i+12"

Or perhaps you don't need a 2nd loop if j is always equal to i+12. This might be the case!

[m m]

i'm sorry j=i+1/2 (not j=i+12)

[Adam Danz]

Well then I'm not sure what's going on because loops require integer increments.

[m m]

thank you