說明
這是最優化課程第一次附加作業
依賴
MATLAB2015
題目
運行效果
momentum.m
que1.m
que1
第一題
警告: Gradient must be provided for trust-region algorithm; using quasi-newton algorithm instead.
In fminunc (line 397)
In que1 (line 8)
Initial point is a local minimum.
Optimization completed because the size of the gradient at the initial point
is less than the default value of the optimality tolerance.
<stopping criteria details>
最優點為
x =
3 4
最優值為
fval =
0
que2.m
que2
第二題
Local minimum found that satisfies the constraints.
Optimization completed because the objective function is non-decreasing in
feasible directions, to within the default value of the optimality tolerance,
and constraints are satisfied to within the default value of the constraint tolerance.
<stopping criteria details>
最優點為
x =
15/4 5/4
最優值為
fval =
65/8
que3.m
que3
第三題
> In backsolveSys
In solveAugSystem
In leastSquaresLagrangeMults
In barrier
In fmincon (line 797)
In que3 (line 12)
警告: 矩陣接近奇異值，或者縮放錯誤。結果可能不準確。RCOND = 2.217408e-16。
> In backsolveSys
In solveAugSystem
In leastSquaresLagrangeMults
In nlpStopTest
In barrier
In fmincon (line 797)
In que3 (line 12)
警告: 矩陣接近奇異值，或者縮放錯誤。結果可能不準確。RCOND = 2.217408e-16。
> In backsolveSys
In solveAugSystem
In normalCauchyStep
In normalStep
In computeTrialStep
In barrier
In fmincon (line 797)
In que3 (line 12)
警告: 矩陣接近奇異值，或者縮放錯誤。結果可能不準確。RCOND = 2.217408e-16。
程序
momentum.m
%畫圖
%2.約束條件
x1=[-1:0.5:10];
x2=x1-5/2;
plot(x1,x2);
hold on;
x2=-x1+5;
plot(x1,x2);
hold on;
x1=[-1,10];
x2=[0,0];
plot(x1,x2);
hold on;
x1=[0,0];
x2=[-1,10];
plot(x1,x2);
hold on;
%3.可行域
[X1,X2]=meshgrid(-1:0.1:9,-1:0.1:9);
idx=(-X1+X2<=-5/2)&(X1+X2<=5)&(X1>=0)&(X2>=0);
x1=X1(idx);%行重復數量
x2=X2(idx);%列匹配行
k=convhull(x1,x2);
fill(x1(k),x2(k),'c')
title('可行域')
axis equal
%4.目標函數等值線
[x1,x2]=meshgrid(-2:0.1:8,-2:0.1:8);
target_f=(x1-3).^2+(x2-4).^2;
[C,h]=contour(x1,x2,target_f);
set(h,'ShowText','on','TextStep',get(h,'LevelStep'))
hold on;
%5.最優解
%見另三個文件
%1.坐標系
axis on;grid on;axis([-2,7,-2,7]);
xlabel('x1');ylabel('x2');
que1.m
%(1)
disp('第一題');
format rat;
fun=@(x)(x(1)-3)^2+(x(2)-4)^2;
x0=[3,4];
[x,fval]=fminunc(fun,x0);
disp('最優點為');
x
disp('最優值為');
fval
que2.m
%(2)
disp('第二題');
format rat;
fun=@(x)(x(1)-3)^2+(x(2)-4)^2;
x0=[3,4];
A=[-1,1;1,1];
b=[-5/2,5];
Aeq=[];
beq=[];
lb=zeros(2,1);
[x,fval]=fmincon(fun,x0,A,b,Aeq,beq,lb);
disp('最優點為');
x
disp('最優值為');
fval
que3.m
%(3)
disp('第三題');
format rat;
fun=@(x)(x(1)-3)^2+(x(2)-4)^2;
x0=[3,4];
A=[-1,1;1,1];
b=[-5/2,5];
Aeq=[1,-1];
beq=[0];
lb=zeros(2,1);
[x,fval]=fmincon(fun,x0,A,b,Aeq,beq,lb);
disp('最優點為');
x
disp('最優值為');
fval
