最优捕鱼策略问题(2)

2018-12-19 22:47

total=-mtotal a10=eval(a10) a20=eval(a20) a30=eval(a30) a40=eval(a40) format short clear

buyu.m

function y=buyu(x);

global a10 a20 a30 a40 total k; syms k a10;

x1=dsolve('Dx1=-0.8*x1','x1(0)=a10'); t=1;

a20=subs(x1);

x2=dsolve('Dx2=-0.8*x2','x2(0)=a20'); t=1;

a30=subs(x2);

x31=dsolve('Dx31=-(0.8+0.4*k)*x31','x31(0)=a30'); t=2/3;

a31=subs(x31);

x32=dsolve('Dx32=-0.8*x32','x32(2/3)=a31'); t=1;

a40=subs(x32);

x41=dsolve('Dx41=-(0.8+k)*x41','x41(0)=a40'); t=2/3;

a41=subs(x41);

x42=dsolve('Dx42=-0.8*x42','x42(2/3)=a41'); t=2/3;

a31=subs(x31);

nn=1.109*10^5*(0.5*a31+a41);

Equ=a10-nn*1.22*10^11/(1.22*10^11+nn); S=solve(Equ,a10); a10=S(2,1); syms t; k=x;

t3=subs(subs(int(0.42*k*x31,t,0,2/3))); t4=subs(subs(int(k*x41,t,0,2/3))); total=17.86*t3+22.99*t4; y=subs((-1)*total) 6

运行结果为：

k =

18.25976795085083

total =

4.080548655562244e+011

a10 =

1.195809275167686e+011

a20 =

5.373117428928620e+010

a30 =

2.414297288420686e+010

a40 =

8.330238542343275e+007 >>

运行图为：

x 10114.154.14.0543.953.93.853.83.750510152025

function y=buyu(x); %Function应为function global a10 a20 a30 a40 total k; syms k a10;

x1=dsolve('Dx1=-0.8*x1','x1(0)=a10'); %单引号须为英文下的单引号 t=1;a20=subs(x1);

x2=dsolve('Dx2=-0.8*x2','x2(0)=a20'); t=1;a30=subs(x2);

x31=dsolve('Dx31=-(0.8+0.4*k)*x31','x31(0)=a30'); t=2/3;a31=subs(x31);

x32=dsolve('Dx32=-0.8*x32','x32(2/3)=a31'); t=1;a40=subs(x32);

x41=dsolve('Dx41=-(0.8+k)*x41','x41(0)=a40'); %多了一个*号，已删。 t=2/3;a41=subs(x41);

x42=dsolve('Dx42=-0.8*x42','x42(2/3)=a41'); t=2/3;a31=subs(x31);

nn=1.109*10^5*(0.5*a31+a41); %N应为n Equ=a10-nn*1.22*10^11/(1.22*10^11+nn);

S=solve(Equ,a10); a10=S(2,1); %eq1应为Equ Syms t; k=x;

t3=subs(subs(int(0.42*k*x31,t,0,2/3))); t4=subs(subs(int(k*x41,t,0,2/3))); total=17.86*t3+22.99*t4;

y=subs((-1)*total);

以下为buyu1.m

global a10 a20 a30 a40 total; [k,mtotal]=fminbnd('buyu', 0,20); Ezplot(total,0,25) Xlabel('') ylabel('') title('')

format long; k

total=-mtotal a10=eval(a10) a20=eval(a20) a30=eval(a30) a40=eval(a40) format short clear

运行结果： k =