matlab 运行ode45出错，不知道什么原因，麻烦帮我找找什么错误

Question

用文献中的一小段程序，计算发动机进气质量，但是积分一直出错，不知道怎么修改
运行后提示错误：
1、Error using odearguments (line 93)
FA returns a vector of length 0, but the length of initial conditions vector is 1. The vector returned
by FA and the initial conditions vector must have the same number of elements.
2、Error in ode45 (line 114)
[neq, tspan, ntspan, next, t0, tfinal, tdir, y0, f0, odeArgs, odeFcn, ...
3、Error in Untitled3 (line 12)
[anng2,ma1]=ode45(@fa,t,mass0)
程序如下：

d=7.5;s=8;l=13;volc=188;R=287.1;Temp=298;angla=200*pi/180;qang=20;
vol0=fvol(d,s,l,(360-qang)*pi/180,volc);
mass0=0.1*vol0./(R*Temp);
t=(210-qang)*pi/180:0.1:220*pi/180;
[anng2,ma1]=ode45(@fa,t,mass0)

function dmassa=fa(angla,massa)
global n
global Temp
d=7.5;
s=8;
l=13;
dia=21.8;
beta=pi/4;
volc=188;
pre=0.1;
k=1.4;
R=287.1;
angla=200*pi/180;
ang=angla+150*pi/180;
vol=fvol(d,s,l,ang,volc);
ara=fara(dia,beta,angla);
if ara<=pi*dia^2/4
ara=fara(dia,beta,angla);
else
ara=pi*dia^2/4;
end
if vol*pre./(massa*R*Temp)<=(2/(k+1))^(k/(k-1))
G=(2/(k+1))^(1/(k-1))*sqrt(2*k/(k+1));
dmassa=-ara*sqrt(R*Temp)*massa./vol*G*(30./(pi*n));
else
G=sqrt((2*k/(k-1))*((( vol*pre./(massa*R*Temp))^(2/k)-...
( vol*pre./(massa*R*Temp))^((k+1)/k))));
dmassa=-ara*sqrt(R*Temp)*massa./vol*G*(30./(pi*n));
end

function area=fara(dia,beta,angla)
area=pi*fha(angla)*cos(beta)*(dia+fha(angla)*cos(beta)*sin(beta));

function volume=fvol(d,s,l,angle,volc)
volume=volc+pi/4*d^2*s/2*((1+2*l/s)-cos(angle)-sqrt((2*l/s)^2-sin(angle).^2));

Answer 1

看看fa计算结果多少