Why if statement with odd and even number does not work in function and just skipped condition?

Hello everyone! Does someone know why this code

if mod(plane,2) == 0 %even

ThetaBar = Theta0;

fprintf('ThetaBar: %f\n',ThetaBar);

else

ThetaBar = 90 - Theta0; %odd

fprintf('ThetaBar: %f\n',ThetaBar);

end

does not work inside of function properly. Idea is if plane if odd then ThetaBar = 90 - Theta0, else if plane is even then ThetaBar = Theta0. I run two function in main. But it does not calculate ThetaBar(ii) as I expect. It seems like code just skipped my statement.

Thank you in advance. Appreciate any help

function [p, Xr, Yr, Zr, ThetaBar, PhiBar, tempPlane] = planeLocation5(XBar, YBar, ZBar,X0,Y0,Z0,Theta0, Phi0)

planes(:,:,1) = [0 3 3; 0 0 3; 0 3 0; 0 0 0; 0 0 0];

planes(:,:,2) = [0 0 3; 3 0 3; 0 0 0; 3 0 0; 0 0 0];

planes(:,:,3) = [3 0 3; 3 3 3; 3 0 0; 3 3 0; 3 0 0];

planes(:,:,4) = [3 3 3; 0 3 3; 3 3 0; 0 3 0; 0 3 3];

planes(:,:,5) = [0 3 0; 3 3 0; 0 0 0; 3 0 0; 0 0 0];

planes(:,:,6) = [0 3 3; 3 3 3; 0 0 3; 3 0 3; 0 0 3];

location_plane = 6;

....

if mod(plane,2) == 0 %even

ThetaBar = Theta0;

fprintf('ThetaBar: %f\n',ThetaBar);

else

ThetaBar = 90 - Theta0; %odd

fprintf('ThetaBar: %f\n',ThetaBar);

end

and then I run in main

clc

clear all

close all

X0 = 1.5;

Y0 = 1.5;

Z0 = 3.0;

Theta0 = 60;

Phi0 = 90;

K = 5;

X = [X0 zeros(1,K)];

Y = [Y0 zeros(1,K)];

Z = [Z0 zeros(1,K)];

Theta = [Theta0 zeros(1,K)];

Phi = [Phi0 zeros(1,K)];

for ii = 1:K

ii

X(ii)

Y(ii)

Z(ii)

Theta(ii)

Phi(ii)

[XBar, YBar, ZBar] = reflection5(X(ii), Y(ii), Z(ii), Theta(ii), Phi(ii));

[p, Xr, Yr, Zr, ThetaBar, PhiBar, tempPlane] = planeLocation5(XBar, YBar, ZBar,X(ii), Y(ii), Z(ii),Theta(ii), Phi(ii));

%if plane == 0 || plane == 2 || plane == 4 %even

% ThetaBar = Theta(ii);

%else

% ThetaBar = 90 - Theta(ii); %odd

%end

X(ii+1) = Xr;

Y(ii+1) = Yr;

Z(ii+1) = Zr;

Theta(ii+1) = ThetaBar;

Phi(ii+1) = PhiBar;

end

[Mathieu NOE]

hello

function reflection5 is missing, we cannot fully test your code

in function planeLocation5 , we do not see where the variable plane comes from , so again we cannot test why the odd / even test fails

Answer 1

[Cameron]

I suspect what's happening is that you're passing a vector or array into your mod() function. If all elements of your variable "plane" are not even, it will send you to the else portion of your code. See this for example

x = [2,3;2,2]; %all these numbers are not even
if mod(x,2) == 0 
    disp('All numbers in array are even')
else
    disp('All numbers in array are not even')
end

All numbers in array are not even

%and compare it with this
x2 = [2,2;2,2]; %all these numbers are not even
if mod(x2,2) == 0 
    disp('All numbers in array are even')
else
    disp('All numbers in array are not even')
end

All numbers in array are even

[Aknur]

Dear, @Cameron thank you it works now. I also mixed up odd and even