Plot 3D of coinstraned optimization
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Good evening, for my thesis I should make a 3d plot in which I want something similar to this:
I have a function f(x,y)=x^2-2*x+1+y^2 subject to constraints g(x,y)=x^4+y^4-1.
I'm interested only in the plot.
采纳的回答
Use this,
https://www.mathworks.com/matlabcentral/fileexchange/74010-getcontourlinecoordinates?s_tid=srchtitle
[X,Y]=ndgrid(linspace(-2,2,500));
G=X.^4+Y.^4;
cm = contourf(X,Y,G,1); close
[~, cA] = getContourLineCoordinates(cm);
f=@(x,y)x.^2-2*x+1+y.^2;
fsurf(f,[-4,4],'FaceColor','b','FaceAlpha',0.3,'EdgeColor','none'); hold on
for i=1:numel(cA)
x=cA{i}(:,1);
y=cA{i}(:,2);
z=f(x,y);
line(x,y,z,'COlor','r','LineWidth',2)
end
hold off
xlabel X; ylabel Y; view(150,-2)
更多回答（1 个）
Torsten
2022-4-11
x=-2:0.01:2;
y=-2:0.01:2;
[X,Y] = meshgrid(x,y);
Z = X.^2-2*X+1+Y.^2;
xx=-1:0.01:1;
yy=-1:0.01:1;
y1 = (1-xx.^4).^(0.25);
y2 = -(1-xx.^4).^(0.25);
z1 = xx.^2-2*xx+1+y1.^2;
z2 = xx.^2-2*xx+1+y2.^2;
surf(X,Y,Z)
hold on
plot3(xx,y1,z1,'Linewidth',4,'Color','red')
hold on
plot3(xx,y2,z2,'Linewidth',4,'Color','red')
view([2,2,4])
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