function?[tSIR]?=?differentialSIR（NbetagammaMaxTime）
%
%?
%
%?RISK_STRUCTURE（?beta?gamma?S0?I0?MaxTime）
%??????This?is?the?MATLAB?version?of?program?2.1?from?page?19?of?
%?“Modeling?Infectious?Disease?in?humans?and?animals“?
%?by?Keeling?&?Rohani.
%?
%?It?is?the?simple?SIR?epidemic?without?births?or?deaths.%?
%

%?Sets?up?default?parameters?if?necessary.
I0?=?100?/?N;
S0?=?1?-?I0;

%?Checks?all?the?parameters?are?valid
if?S0<=0?
????error（‘Initial?level?of?susceptibles?（%g）?is?less?than?or?equal?to?zero‘S0）;
end

if?I0<=0?
????error（‘Initial?level?of?infecteds?（%g）?is?less?than?or?equal?to?zero‘I0）;
end

if?beta<=0?
????error（‘Transmission?rate?beta?（%g）?is?less?than?or?equal?to?zero‘beta）;
end
????
if?gamma<=0?
????error（‘Recovery?rate?gamma?（%g）?is?less?than?or?equal?to?zero

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件???????12292??2016-01-22?19:37??YBJAN1916_SIR?model?in?whole?population\.DS_Store
?????目錄???????????0??2020-01-30?10:08??YBJAN1916_SIR?model?in?whole?population\SIR\
?????文件????????1295??2016-01-22?19:38??YBJAN1916_SIR?model?in?whole?population\SIR\SIR.m
?????文件????????1536??2016-01-19?02:31??YBJAN1916_SIR?model?in?whole?population\SIR\differentialSIR.m
?????文件????????2361??2016-01-19?02:40??YBJAN1916_SIR?model?in?whole?population\SIR\discreteSIR.m
?????文件?????????910??2016-01-19?02:40??YBJAN1916_SIR?model?in?whole?population\SIR\mean_fieldSIR.m
?????目錄???????????0??2020-01-30?10:08??YBJAN1916_SIR?model?in?whole?population\