How to insert constant offset into cumtrapz calculation?

I am doing data analysis according to the following equations from my professor.

For part of my data set, I want to use the cumtrapz function "normally" and for part of it I want to subtract a constant within the summation expression (C_p_baseline, as seen above). I have tried using the two options below and neither one worked. The output for each method is shown in the graphs below. I do not understand where the discontinuity comes from as the curve should decrease gradually from the maximum. I have attached the entire code so you can see the data. Any suggestions on how to embed the subtraction within the cumtrapz function like my professor showed?

Option 1:

H11 = cumtrapz(TC1(1:Tm),Cp1(1:Tm));

H12 = cumtrapz(TC1(Tm:end),Cp1(Tm:end)-dCp1);

Option 2:

H11 = cumtrapz(TC1(1:Tm),Cp1(1:Tm));

H12 = cumtrapz(TC1(Tm:end),Cp1(Tm:end))-dCp1;

[Torsten]

We can't comment since we don't know your data.

But it should be clear that

H12 = H11(end) + cumtrapz(TC1(Tm:end),Cp1(Tm:end)-dCp1);

instead of

H12 = cumtrapz(TC1(Tm:end),Cp1(Tm:end)-dCp1);

Answer 1

[Nipun]

Hi Anna,

I understand that you are trying to subtract a constant or provide an offset to summation expression similar to the set of the equations provided.

Having gone through the attached code, it is difficult to infer the reason to the discountinuity due to lack of modelling data.

However, it is evident from the set of expressions that the following line should be mended:

H12 = cumtrapz(TC1(Tm:end),Cp1(Tm:end)-dCp1);

Consider rewriting the code to include the offset outside of the function, like:

H12 = H11(end) + cumtrapz(TC1(Tm:end),Cp1(Tm:end)-dCp1);

Hope this helps.

Regards,

Nipun