how to make fuction from changing varibles

hello everyone !

in my graduate of mechanical engeneering , i need to test function with 3-5 varibles.

the problem that all varibles are nedd to change and finally i need to take tha value of my function

i have differnet boundries for each varible. for example :

Z(a,b,c)

a - angle, between 0 to pi [rad[

b - distance, between 440 to 3010 [mm]

c - load, between 0-4000 [N]

i need to test Z function in al the combinations between the varibles, finally i need to test my function at the max value ans in the min value.

how can i do it ?

thanks about the helping

tal shmuel

Answer 1

[Star Strider]

That is relatively straightforward to do with ndgrid or meshgrid.

Try this hypothetical example:

Z = @(x,y,z) x.^2 + y.^2 + z.^2;                    % Create ‘Z’

a = linspace(0, pi, 5);                             % Define Vector
b = linspace(440, 3010, 4);                         % Define Vector
c = linspace(0, 4000, 3);                           % Define Vector

[A,B,C] = ndgrid(a,b,c);                            % Create Matrices From Vectors
Zout = Z(A(:),B(:),C(:));                           % Creates Appropriate Column Vectors For All Elements Of Original Vectors

[Zmax,ixmx] = max(sum(Zout,2));
[Zmin,ixmn] = min(sum(Zout,2));

Use your own ‘Z’ and your own method of assessing its values.

[tal shmuel]

can i make from all results kinds of 3D graphs ?

[Star Strider]

That depends.

If you choose two independent variables and the output of ‘Z’, then probably: Yes.

From my example here:

Z = @(x,y,z) x.^2 + y.^2 + z.^2;                    % Create ‘Z’

a = linspace(0, pi, 5);                             % Define Vector
b = linspace(440, 3010, 4);                         % Define Vector
c = linspace(0, 4000, 3);                           % Define Vector

[A,B,C] = ndgrid(a,b,c);                            % Create Matrices From Vectors
Zout = Z(A(:),B(:),C(:));                           % Creates Appropriate Column Vectors For All Elements Of Original Vectors

[Zmax,ixmx] = max(sum(Zout,2));
[Zmin,ixmn] = min(sum(Zout,2));

Av = A(:);
Bv = B(:);
Zv = Zout(:);

figure
stem3(Av, Bv, Zv,'.')
grid on

Since 3D plots are restricted to 3 dimensions, only some combinations of variables and the function output are possible.