nstage.m

大气层内航天器飞行动力学matlab仿真模型

% Copyright Ashish Tewari (c) 2006
function p=Nstage(vf,beta,epsilon,alpha);
N=size(beta,1);
p=0.1;
f=vf;
tol=1e-9;
for k=1:N
f=f+beta(k)*log(epsilon(k)+alpha(k)*(1-epsilon(k))*p);
end
while abs(f)>tol
f=vf;
fp=0;
for k=1:N
f=f+beta(k)*log(epsilon(k)+alpha(k)*(1-epsilon(k))*p);
fp=fp+alpha(k)*beta(k)/(epsilon(k)+alpha(k)*(1-epsilon(k))*p);
end
d=-f/fp;
p=p+d;
end