can not find parameter estimation

Hi

I am working on the following code

function Mouna

function dydt=kinetics(p,t,y)

y0=[26 16.4 14.6 0.069 0.84 1.1 0.05 12.1 12.1 0.48 0.2 520 1 0.21 0.1];

[t,y]=ode45(@kinetics,t,y0);

%

dydt=zeros(15,1); %initialize

%Hydrogen production

%growth coefficient

u1=p1*y(2)/(p2+y(2));

%Differential equations

dydt(1)= -p(3)*y(1)-p(4)*y(3)*y(1)+p(3)*p(5)*p(6); %S0 g/L

dydt(2)= -p(3)*y(2)+p(4)*y(3)*y(1)-u1*y(3)/p(7); %S1 g/L

dydt(3)=u1*y(3)-p(3)*y(3); %X1 g/L

dydt(4)=u1*y(3)/p(8)-p(3)*y(4); %Pr1 g/L

dydt(5)=u1*y(3)/p(9)-p(3)*y(5); %But1 g/L

dydt(6)=u1*y(3)/p(10)-p(3)*y(6); %Ac1 g/L

%Hydrogen rate

y(7)=p(11)*u1*y(3); %H2 g/L

%**********************************************************************************************************************

%Methane production

%kinetic equations

ufBut2=p(12)*y(11)/(p(13)+y(11));

ufPr2=p(14)*y(10)/(p(15)+y(10));

qfBut2=p(16)*y(11)/(p(13)+y(11));

qfPr2=p(17)*y(10)/(p(15)+y(10));

um=p(18)*y(14)/(p(19)+y(14));

qm=p(20)*y(14)/(p(21)+y(14));

ue=p(22)*y(14)/(p(23)+y(14));

qe=p(24)*y(14)/(p(23)+y(14));

%VFA differential equations

dydt(8)=ufPr2*y(8)-p(25)*y(8)-p(26)*y(8); %XfPr2

dydt(9)=ufBut2*y(9)-p(25)*y(9)-p(26)*y(9); %XfBut2

dydt(9)= -qfPr2*y(8)+p(27)*(y(5)-y(10)); %Pr2

dydt(9)= -qfBut2*y(9)+p(27)*(y(6)-y(11)); %But2

dydt(12)=um*y(12)-p(28)*y(12)-p(29)*y(12); %Xm

dydt(13)=ue*y(13)-p(30)*y(13)-p(31)*y(13); %Xe

dydt(14)= -qe*y(14)-qm*y(12)+p(27)*(y(7)-y(14)); %Ac2

%Methane rate

y(15)=p(32)*qm*(y(13)+y(14))*p(33);

end

t=[26 16.4 14.6 0.069 0.84 1.1 0.05 12.1 12.1 0.4 0.2 520 1 0.21 0.1];

yexp=[26 16.4 12.4 0.118 1.888 2.64 1.64 12.1 12.1 0.55 0.3 12.1 12.1 0.2 2.58

2402 16.02 11.87 0.145 1.678 2.53 1.6 11.56 11.56 0.24 0.4 11.56 11.56 0.195 2.58

20.8 14.89 11.02 0.145 1.972 2.75 1.63 10.72 10.72 0.34 0.15 10.72 10.72 0.211 2.46

18 13.34 10.59 0.152 1.982 2.725 1.68 10.01 10.01 0.22 0.12 10.01 10.01 0.19 2.52

17.65 11.79 9.63 0.138 1.89 2.73 1.7 9.32 9.32 0.28 0.11 9.32 9.32 0.216 2.56

16.98 9.8 8.88 0.145 1.806 2.65 1.7 8.67 8.67 0.24 0.14 8.67 8.67 0.22 2.54

15.4 7.8 8 0.143 1.982 2.77 1.69 7.85 7.85 0.2 0.13 7.85 7.85 0.22 2.65

14.2 6.2 7.21 0.16 1.962 2.79 1.65 6.95 6.95 0.2 0.15 6.95 6.95 0.221 2.62

13 4.9 6.53 0.163 2.184 2.86 1.8 6.02 6.02 0.2 0.27 6.02 6.02 0.288 2.61

10.4 3.2 5.03 0.173 2.037 284 1.81 5.34 5.34 0.34 0.24 5.34 5.34 0.293 2.6];

p0=[0.586;3.914;3.914;1;1;16.4;0.08;4.2;2.1;1.2;0.05;0.05;0.22;0.05;0.22;12;14;0.3;80;0.05;20;0.05;20;0.04;0.1;4.12;0.01;0.2;0.01;0.2;122;2.2;2.2];

p=lsqcurvefit(@kinetics,p0,t,yexp);

fprintf(1,'\tRate Constants:\n')

for k1 = 1:length(p)

fprintf(1, '\t\tp(%d) = %8.5f\n', k1, p(k1))

end

tv = linspace(min(t), max(t));

yfit = kinetics(p, tv);

end

I got

Caused by:

Failure in initial user-supplied objective function evaluation.

LSQCURVEFIT cannot continue.