multiple variables fitting with lsqnonlin
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my curve fitting with lsqnonlin has poor fit. what is wrong?
clear;
X0 = [0.1; 0.1; 0.1; 0.1];
no = 520;
no_data = 520;
H_total = 0;
time = load('time_BS19.m');
dqdt = load('Q_BS19.m');
temp = load('temp_BS19.m');
baseline = zeros(no,1);
alpha = zeros(no,1);
dadt = zeros(no,1);
gradient = ( dqdt(no,1) - dqdt(1,1) ) / ( time(no,1) - time(1,1) );
for i = 1 : no
baseline(i,1) = dqdt(1,1) + gradient * ( time(i,1) - time(1,1) );
end
for i = 2 : no
H_total = H_total + ( dqdt(i,1) - baseline(i,1) ) * ( time(i,1) - time(i-1,1) ) ;
end
for i = 2 : no
alpha(i,1) = alpha(i-1,1) + ( ( dqdt(i,1) - baseline(i,1) ) * ( time(i,1) - time(i-1,1) ) ) / H_total;
end
for i = 1 : no
dqdt(i,1) = dqdt(i,1) - baseline(i,1);
end
for i = 1 : no
dadt(i,1) = dqdt(i,1) / H_total;
end
for i = 1 : no_data
X(i,1) = alpha( (i-1)*1+1 ,1);
Y(i,1) = dadt( (i-1)*1+1 ,1);
end
X(1,1) = alpha(1,1)+0.00001;
X(no_data,1) = alpha(no,1)-0.00001;
Y(no_data,1) = dadt(no,1);
options = optimset ('Largescale','off');
x=lsqnonlin(@fitting_epoxy_isothermal,X0,[],[],options,X,Y);
xt=real(x);
x=xt;
Y_sim = ( x(1) + x(2) * (alpha).^ x(3)).* ( 1-alpha).^ (x(4));
alpha_sim(1,1) = 0;
for i = 2 : no
alpha_sim(i,1) = alpha_sim(i-1,1) + Y_sim(i,1) * ( time(i,1) - time(i-1,1) ) ;
end
sr=187.5; % shear rate (s^-1)
macosko_0=[3*10^(-9), 6000, 10^(9), 0.2, 0.6, 2, -0.1]; % B, Tb, tau*, n, alpha_g(>alpha), c1, c2
no_ext=702; % alpha > 0 이 되는 부분 앞으로 배열요소 확장(점도측정 시작지점)
temp_ext=load('temp_BS19_ext.m');
alpha_ext=zeros(no_ext,1);
time_ext=load('time_BS19_ext.m');
eta_ext=load('eta_BS19_ext.m');
temp_ext=temp_ext+273.15;
for i=1:(no_ext-no)
alpha_ext(i)=0;
end
for i=(no_ext-no+1):no_ext % 배열요소 확장
alpha_ext(i)=alpha(i-(no_ext-no));
end
options = optimset ('Largescale','off','Display','iter');
% options = optimset ('FunValCheck','on');
%[macosko] = lsqnonlin(@(macosko)fitting_macosko(macosko,temp_ext,alpha_ext,eta_ext),macosko_0);
macosko=lsqnonlin(@fitting_macosko,macosko_0,[],[],options,temp_ext,alpha_ext,eta_ext);
mt=real(macosko);
macosko=mt;
eta_sim=zeros(no_ext,1);
% eta_sim=macosko(1)*exp(macosko(2)./temp_ext)./(1+(macosko(1)*exp(macosko(2)./temp_ext)*sr/macosko(3))).^(1-macosko(4)).*(macosko(5)/(macosko(5)-alpha_ext)).^(macosko(6)+macosko(7).*alpha_ext);
for i=1:no_ext
eta_sim(i) = macosko(1)*exp(macosko(2)./temp_ext(i))./(1+((macosko(1)*exp(macosko(2)./temp_ext(i))*sr/macosko(3)).^(1-macosko(4)))).*(macosko(5)/(macosko(5)-alpha_ext(i))).^(macosko(6)+macosko(7).*alpha_ext(i));
end
plot3(temp_ext,alpha_ext,eta_ext,'bo')
hold on
plot3(temp_ext',alpha_ext,eta_sim,'r')
figure(5)
semilogy(temp_ext, eta_ext, 'bo', temp_ext, eta_sim, 'r')
xlabel('temp (K)');
ylabel('viscosity (Pa.s)');
% grid on;
my objective function is
function parameters = fitting_epoxy_isothermal(x,X,Y)
parameters = ( x(1) + x(2) * X.^ x(3) ).* ( 1-X ).^ (x(4)) - Y;
function parameter = fitting_macosko(macosko,temp_ext,alpha_ext,eta_ext) % alpha_rheo 의 앞 배열을 0으로 확장 필요
sr=187.5; % shear rate (s^(-1)) 기입
parameter = macosko(1)*exp(macosko(2)./temp_ext)./(1+((macosko(1)*exp(macosko(2)./temp_ext)*sr/macosko(3)).^(1-macosko(4)))).*(macosko(5)/(macosko(5)-alpha_ext)).^(macosko(6)+macosko(7).*alpha_ext)-eta_ext;
5 comentarios
Yongchul Shin
el 27 de Sept. de 2019
Yongchul Shin
el 27 de Sept. de 2019
Yongchul Shin
el 27 de Sept. de 2019
Adam Danz
el 27 de Sept. de 2019
Sorry, that's too much copy-pasting and variable naming for me. If the data are attached so I can load them using your code, I can take a look at it.
Respuestas (1)
Yongchul Shin
el 27 de Sept. de 2019
0 votos
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