Hello, this is the matlab message: "Undefined operator '*' for input arguments of type 'LinearModel'"

load ('DATI_PAZ1');

LV_1=LV;

lat_1=lat;

sept_1=sept;

time_1=time;

load ('DATI_PAZ2');

LV_2=LV;

lat_2=lat;

ant_2=ant;

time_2=time;

figure

plot(time_1,LV_1,'k')

hold on

plot(time_1,lat_1,'b')

hold on

plot(time_1,sept_1,'r')

grid on

xlabel('time [s]'),ylabel('colpi/(s*voxel)')

title('Conc. FDG - CASO I')

legend('ventr.sx','laterale','setto')

figure

plot(time_2,LV_2,'k')

hold on

plot(time_2,lat_2,'b')

hold on

plot(time_2,ant_2,'r')

grid on

xlabel('time [s]'),ylabel('colpi/(s*voxel)')

title('Conc. FDG - CASO II')

legend('ventr.sx','laterale','anteriore')

y_lat_1=lat_1./LV_1;

y_sept_1=sept_1./LV_1;

x_1=cumtrapz(time_1,LV_1)./LV_1;

figure

subplot(1,2,1)

plot(x_1,y_lat_1,'*b')

hold on

plot(x_1,y_sept_1,'*r')

title('Patlak graph - CASO I')

F_sept_1=fitlm(x_1(18:24,1),y_sept_1(18:24,1),'poly1');

hold on

plot(F_sept_1)

F_lat_1=fitlm(x_1(18:24,1),y_lat_1(18:24,1),'poly1');

hold on

plot(F_lat_1)

legend('parete laterale','setto')

xlabel('trapz( C_p(t) dt)/C_p(t) [s]'),ylabel('C_t(t)/C_p(t) [adimensionale]')

m_setto_1=F_sept_1;

m_laterale_1=F_lat_1;

LC = 0.67;

Cp = 100/100;%mg/cm^3 passaggio da dl a cm^3

rho=1.08;%g/cm^3

R_setto_1=m_setto_1*60*Cp/LC*(1/rho); %error

R_laterale_1=m_laterale_1*60*Cp/LC*(1/rho); %error

Answer 1

[Sameer]

Hi Gabriele

The error message you're encountering, "Undefined operator '*' for input arguments of type 'LinearModel'," indicates that you are trying to use the multiplication operator * with a LinearModel object, which is not directly supported in MATLAB.

The "fitlm" function returns a LinearModel object, which contains information about the fitted model, but it is not a numeric value that can be directly multiplied.

To resolve this, extract the slope (coefficient) from the LinearModel object before performing the multiplication. Here's how you can modify the code:

% Assuming F_sept_1 and F_lat_1 are LinearModel objects from fitlm
m_setto_1 = F_sept_1.Coefficients.Estimate(2); % Extract the slope (second element)
m_laterale_1 = F_lat_1.Coefficients.Estimate(2); % Extract the slope (second element)
LC = 0.67;
Cp = 100/100; % mg/cm^3 conversion from dl to cm^3
rho = 1.08; % g/cm^3
% Now you can perform the multiplication
R_setto_1 = m_setto_1 * 60 * Cp / LC * (1 / rho);
R_laterale_1 = m_laterale_1 * 60 * Cp / LC * (1 / rho);

Please refer to the below MathWorks documentation link:

https://www.mathworks.com/help/stats/fitlm.html

Hope this helps!

[Gabriele Maduri]

it's ok! Thanks so much!