Hi Stéphane
Thank you for showing me how to work ODE.
P.S. about Corona modeling, the model by Risbo is nice in that you can
implement a lockdown of some sort. It's a simple one-step lockdown,
where you have to tune the R-value ... in reality each geographic area
is different, related to how much of a lockdown is executed, how dense
the population is, etc.
Cheers,
Claus
On 4/30/2020 4:51 PM, Stéphane Mottelet wrote:
Hi Clauss,
Just modify the following lines :
t1 = 0:0.1:60;
y1 = ode(y0, 0, t1, odefun); // [t1,y1] = ode45(@odefun,[0 60],y0); //
run 1st scernario
idx=[3:6];
scf();
a = gca();
plot(Begin+t1,y1(idx,:),'-'); //
semilogy(Begin+t1,y1(:,idx),'-','LineWidth',3) And you will be fine. ode()
needs a vector of time values and the output is oriented transposed w.r.t
Matlab output.
S.
Le 30/04/2020 à 16:40, Claus Futtrup a écrit :
functiondydt=odefun(t, y)ift<daysR=R0;elseR=0.6;// Change
reproductive rate after
lockdownendA=[00-delta*R*y(1)/Npop000;...0-gamdelta*R*y(1)/Npop000;...0gam-delta000;...00delta*(1-Fhosp)000;...00delta*Fhosp0-1/Thosp0;...00delta*R*y(1)/Npop000];dydt=A*y;endBegin=datenum(2020,02,20,0,0,0);//
begin dateDlock=datenum(2020,03,12,0,0,0);// date of
lockdowndays=Dlock-Begin;R0=2.6;// inital R valuegam=1/3;// gamma,
the inverse of average latent timedelta=1/5;// inv time constant
which infectious people either recover or enter hospitalFhosp=0.16;//
fraction of recovering people going to hospitalThosp=14;// average
time of hospitalisationNpop=6e6;// total initial population of
sensitivey0=[Npop;50;50;0;0;0];// [S E I R Hosp ] intial
cond.t1=0:60;y1=ode(y0,0,60,odefun);// [t1,y1] = ode45(@odefun,[0
60],y0); // run 1st
scernarioidx=[3:6];scf();a=gca();plot(Begin+t1,y1(:,idx),'-');//
semilogy(Begin+t1,y1(:,idx),'-','LineWidth',3)a.log_flags="nln";xlabel('Date')ylabel('Number
of cases')xgrid();// ax=gca;// ax.YLim=[10
max(max(y2(:,idx)))];xtitle({'Danish Corona lock down on 20.03.12, vs
14 days later','R goes from 2.6 to 0.6 at
lockdown'});legend('Infected','Recovered','Hospitalised','Total Cases');
--
Stéphane Mottelet
Ingénieur de recherche
EA 4297 Transformations Intégrées de la Matière Renouvelable
Département Génie des Procédés Industriels
Sorbonne Universités - Université de Technologie de Compiègne
CS 60319, 60203 Compiègne cedex
Tel : +33(0)344234688
http://www.utc.fr/~mottelet
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