2D Surface with periodic structure.

Hello

Below is a section of code that I am working on. The basic idea is to create a surface 30mm square that has a surface that varies according to two sinewave functions. However, my code runs into issue in the Z assignment of the loop. Any help would be appreciated. Also if you have a more compact way

LengthX = 30; % X Length of sample in mm
LengthY = 30; % Y Length of sample in mm
X_k =2; % Number of Periods along X
Y_k =1; % Number of Periods along Y
DegX = pi .* X_k; %Degrees in X
DegY = pi .* Y_k; %Degrees in y
StepSize = 0.05; % Evenly Spaced X,Y gridpoints
x=0:StepSize:LengthX; y= 0:StepSize:LengthY; 
NumXStep = DegX / length(x);
NumYStep = DegY / length(y);
Z = zeros(length(x), length(y));

for Counter = 0:1:length(x)
    for Counter2 = 0:1:length(y)
%       Z =(sin(x)+sin(y)),(-2*pi:0.1:2*pi),(-2*pi:0.1:2*pi);
      Z[Counter, Counter2] = sin(NumXStep*Counter)+sin(NumYStep*Counter)
    end
end

surf(x,y,Z)

Answer 1

[John BG]

Hi Michael

this is John BG <mailto:[e-mail] [e-mail]>

1.

LengthX = .03;   % X Length of sample in mm
LengthY = .03;   % Y Length of sample in mm
X_k =2;     % Number of Periods along X
Y_k =1;     % Number of Periods along Y

2.

Don't need DegX DegY

% DegX = 2*pi*X_k;   % Degrees in X
% DegY = 2*pi*Y_k;   % Degrees in y

3.

The frequencies are needed, but you haven't defined them

T1=.01  % 10mm
T2=.02  % 20mm
f1=1/T1  
f2=1/T2

4.

Reduce the step to avoid poor resolution

StepSize = 0.0005;   % Evenly Spaced X,Y gridpoints
x=[0:StepSize:LengthX]; 
y= [0:StepSize:LengthY];

% don't need for loop either

[X,Y]=meshgrid(x,y)
Z=sin(2*pi*f1*X)+sin(2*pi*f2*Y)

.

if you find this answer useful would you please be so kind to consider marking my answer as Accepted Answer?

To any other reader, if you find this answer useful please consider clicking on the thumbs-up vote link

thanks in advance

John BG

<mailto:[e-mail] [e-mail]>

Answer 2

[Walter Roberson]

In MATLAB, [] is never used for indexing, only for list construction.