# Z must be a matrix, not a scalar or vector

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Kundan Prasad on 17 Aug 2021
Commented: Kundan Prasad on 19 Aug 2021
clc
clear all
R=10;
f=0.5;
s=50;
N=36;
a=f/(s*N);
Ax=0.002;
Ay=0.002;
lx=2.5;
ly=2.5;
n=((R*s*N)/f)+1;
for i=1:n
r(i)=(R-((i-1)*a));
theta(i)= ((i-1)*(2*pi/N));
x(i)=(r(i)*cos(theta(i)));
y(i)=(r(i)*sin(theta(i)));
[xx(i),yy(i)]=meshgrid(x(i),y(i));
Z(i)=((Ax*cos(2*pi*xx(i)/lx))+(Ay*cos(2*pi*yy(i)/ly)));
end
surf(xx,yy,Z);
##### 2 CommentsShowHide 1 older comment
Kundan Prasad on 17 Aug 2021
I want 3d plot and every time i am getting an error that Z must be a matrix, not a scalar or vector

Matt J on 17 Aug 2021
Edited: Matt J on 17 Aug 2021
R=10;
f=0.5;
s=50;
N=36;
a=f/(s*N);
Ax=0.002;
Ay=0.002;
lx=2.5;
ly=2.5;
n=((R*s*N)/f)+1;
for i=1:n
r(i)=(R-((i-1)*a));
theta(i)= ((i-1)*(2*pi/N));
x(i)=(r(i)*cos(theta(i)));
y(i)=(r(i)*sin(theta(i)));
% [xx(i),yy(i)]=meshgrid(x(i),y(i));
Z(i)=((Ax*cos(2*pi*x(i)/lx))+(Ay*cos(2*pi*y(i)/ly)));
end
T=delaunayTriangulation(x(:),y(:));
trisurf(T.ConnectivityList,x(:),y(:),Z(:),'EdgeColor','none','FaceAlpha',0.6);
view(-80,75)
Matt J on 17 Aug 2021
You're welcome, but please Accept-click the answer to indicate that it worked.

Kundan Prasad on 18 Aug 2021
R=10;
f=0.5;
s=50;
N=100;
a=f/(s*N);
Ax=2;
Ay=2;
lx=2.5;
ly=2.5;
n=((R*s*N)/f)+1;
r(0)=0;
Z(0)=0;
t=0.5;
for i=1:n
r(i)=(R-((i-1)*a));
theta(i)= ((i-1)*(2*pi/N));
x(i)=(r(i)*cos(theta(i)));
y(i)=(r(i)*sin(theta(i)));
Z(i)=((Ax*cos(2*pi*x(i)/lx))+(Ay*cos(2*pi*y(i)/ly)));
m(i) = ((Z(i-1) - Z(i))./(r(i-1)-r(i)));
newth(i) = atan(-m(i));
G(i)=r(i)-(t*sin(newth(i)));
H(i)=Z(i)+(t*cos(newth(i)))-t; %% THE compensate value of r1 and Z1
% needed to calculate from the previous value of r(i) and Z(i)
end
T=delaunayTriangulation(x(:),y(:));
trisurf(T.ConnectivityList,x(:),y(:),Z(:),'EdgeColor','none','FaceAlpha',0.6);
view(-80,75)
I am unable to calculate the value of G and H from the previous value of r(i) and Z(i). Can you please check the code. Thank you
Kundan Prasad on 19 Aug 2021
Thank you, now its working