Fit custom equation with two datasets

Hi! I hope you can help me. I have three variables: 'vel', 'i_DC' and 'Delta_p' and two different datasets (attached to this question). The first dataset is '7.csv' which has values of vel; i_DC; Delta_p.

The second dataset is '7.3.csv' which also has values of vel; i_DC; Delta_p.

You can use:

data = readmatrix(path,'Delimiter',';', 'DecimalSeparator','.');

to read the .csv file in path.

These are the plots for both datasets:

I have got this:

p_1_DCPM = 0.026336768345737668

p_2_DCPM = 0.06247573122771201

p_1_USR = 0.008774568384398839

p_2_USR = 0.18027590216652215

p_1_AFPM = 0.0073293204291639494

p_2_AFPM = 0

Delta_p = (p_2_DCPM + p_2_DSR + p_2_USR + p_2_AFPM) * vel + p_1_DCPM * vel.^(4/3) + (p_1_DSR + p_1_USR + p_1_AFPM) * vel.^2 + p_3 _DSR * i_DC.^p_4_DSR

I want to determine the values of the parameters: p_1_DSR; p_2_DSR; p_3 _DSR; p_4_DSR.

Thank you.

Answer 1

[Torsten]

help lsqcurvefit

[Luciano Montanelli]

Thanks @Torsten for your suggestion.