Integration of one array variable wrt other array variable

Hi

I am trying to integrate the current with respect to time to get polarization value. i have both time and current array can anyone help me with this to get proper integration

I am currently using following code:

Thickness = 15*10^-4;
Area = 350

data = readtable('Good PE Loop.txt')

time = data{:,1}
current= data{:,4}
polarization =data{:,5}
field = data{:,2}/Thickness

plot(time,current)
p1 = cumtrapz(current)
p = (10^5/3.5)*p1
plot(time,p)
plot(field,p)

but the value of polarization which im getteing is not correct. and im unable detect the mess up!

thanks in advance!!

• datafile is attached. (my calculated values should be as in the array polarization)

Answer 1

[Amanpreetsingh Arora]

If the time spacing for integration is non uniform, then you will also need to pass the time vector to "cumtrapz" or else it assumes unit spacing for integration. Try passing time vector in the following fashion and see if it yields expected results.

p1 = cumtrapz(time,current)

For more information on function "cumtrapz", refer to the following documentation.

https://in.mathworks.com/help/matlab/ref/cumtrapz.html

[Somnath Kale]

I tried the same thing erlier but still it is not working. there is shift in loop. i wnt it symmetric.

thaks your commets are highly apreciable!!

[Amanpreetsingh Arora]

Please elaborate on your requirements. What do you mean by "there is shift in loop" and what do you want to be symmetric?

[Somnath Kale]

there is some scaling issue. my loop like (a) fig . but what i am getting is somthing eles as in fig (b)

in other way round my "p" array should be like "polarization" array but its not!!

[Amanpreetsingh Arora]

Does the integral have an initial condition? If it has then you will have to add that initial value to "p" becuase "cumtrapz" computes the definate integral considering zero as initial condition.

[Somnath Kale]

can u just add condition from -40 to +40 and wirte small code?