MATLAB Plotting a 3D Gaussian in MATLAB

AI Thread Summary
To plot a three-dimensional Gaussian in MATLAB, the formula A = A0 * exp(-(x^2 + y^2 + z^2)/w^2) is used, where A0 is a scaling factor and w controls the spread of the distribution. The parameter w can be adjusted; a larger value will flatten the distribution. However, since A depends on three variables (x, y, z), a direct 3D plot of A is not feasible. Instead, a common approach is to visualize a Gaussian distribution in two dimensions by fixing one variable, typically z. A sample MATLAB code snippet is provided to create a surface plot for the Gaussian distribution in the x-y plane, using a grid of points for x and y and calculating z accordingly. This method effectively demonstrates the Gaussian shape in a 3D context.
debwaldy
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Homework Statement


Hi all! I'm trying to solve the following problem but I'm not too sure of a few things.
Write Matlab instructions to plot a three dimensional Gaussian:

A = A0exp((x^2 + y^2 + z^2)/w^2)

choosing appropriate values for A0,w and range of coordinates.


Homework Equations


I'm guessing i have to use the plot3 command but after that I'm lost


The Attempt at a Solution


I don't know how to choose appropriate values for all of the variables.And what is w?
I'm a bit lost so I'd really appreciate any hints or tips to point me in the right direction thanks debs:smile:
 
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debwaldy said:

Homework Statement


Hi all! I'm trying to solve the following problem but I'm not too sure of a few things.
Write Matlab instructions to plot a three dimensional Gaussian:

A = A0exp((x^2 + y^2 + z^2)/w^2)

choosing appropriate values for A0,w and range of coordinates.


Homework Equations


I'm guessing i have to use the plot3 command but after that I'm lost


The Attempt at a Solution


I don't know how to choose appropriate values for all of the variables.And what is w?
I'm a bit lost so I'd really appreciate any hints or tips to point me in the right direction thanks debs:smile:

w is a parameter of your Gaussian, make it bigger and the distribution should flatten out.

What exactly do you want to plot? You can't plot A(x,y,z) on a 3D plot because A depends on 3 variables so you would need a 4D plot.

If you want to plot a Gaussian distribution of 2 variables, run the following code in Matlab:
Code:
clear;
pts = -5:.1:5;
N = length(pts);
X = reshape(repmat(pts,1,N),N,N);
Y = reshape(repmat(pts,N,1),N,N);
Z = exp(-X.^2-Y.^2);
figure;surf(X,Y,Z)
Is that the type of plot you are trying to produce?
 

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