# Calculating the difference between a vector and time

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Nikolaos Zafirakis on 4 May 2019
Commented: Star Strider on 5 May 2019
I'm looking for a way to get this loop to work, basically I need to calculate the difference in a 3x1 vector divide by the difference in time. Does anyone have any suggestion?
t = 2000
n= 0;
for ind = 0:1:t
n= n+ind;
S(n) = (diff(x( don't know how to input the value here )))./diff(t(ind)); %x is a three element vector
end
Star Strider on 5 May 2019
If you are ‘padding’ ‘A’ with an initial 0, you need to tell MATLAB.
MATLAB does many things well, although it is sadly deficient when it comes to mind-reading.
Try this:
A = [1 1 2 3];
dA = diff([0 A])
producing:
dA =
1 0 1 1
NOTE — You need to do similar ‘padding’ for your time vector.

Omer N on 5 May 2019
Try this:
A = [1 1 2 3];
A-[0,A(1:end-1)]
ans =
1 0 1 1

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