# make function to plot countour and 3D

1 view (last 30 days)
nirwana on 17 Mar 2023
Answered: Walter Roberson on 17 Mar 2023
Hi, I want to make automatic function to plot 3D mesh and contour to given any function, but it turn doesn't work, can you help me ? here the function that I wrote
function plot3dfunc(f,Xmin,Xmax,Ymin,Ymax)
Z=f;
x=linspace(Xmin,Xmax,50);
y=linspace(Ymin,Ymax,50);
[X,Y] = meshgrid(x,y);
subplot(1,2,1);
cs=contour(X,Y,Z);clabel(cs);
xlabel('x_1');ylabel('x_2');
title('(a) Contour plot');grid;
subplot(1,2,2);
cs=surf(X,Y,Z);
zmin=floor(min(Z));
zmax=ceil(max(Z));
xlabel('x_1');ylabel('x_2');zlabel('f(x_1,x_2)');
title('(b) Mesh plot');
When I put
f=@(X,Y) 2+X-Y+2*X.^2+2*X.*Y+Y.^2;
plot3dfunc(f,-2,0,0,3)
it says :
Error using contour
Input arguments must be numeric or objects which can be converted to double.

Walter Roberson on 17 Mar 2023
f=@(X,Y) 2+X-Y+2*X.^2+2*X.*Y+Y.^2;
plot3dfunc(f,-2,0,0,3)
function plot3dfunc(f,Xmin,Xmax,Ymin,Ymax)
x=linspace(Xmin,Xmax,50);
y=linspace(Ymin,Ymax,50);
[X,Y] = meshgrid(x,y);
Z = f(X,Y);
subplot(1,2,1);
cs=contour(X,Y,Z);clabel(cs);
xlabel('x_1');ylabel('x_2');
title('(a) Contour plot');grid;
subplot(1,2,2);
cs=surf(X,Y,Z);
zmin=floor(min(Z));
zmax=ceil(max(Z));
xlabel('x_1');ylabel('x_2');zlabel('f(x_1,x_2)');
title('(b) Mesh plot');
end

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