How do I get two values of a function when using a loop?

%Ball Trajectory Graph


%Define the for loop first
velocity= [30,40,47.16];
angle=[5,7.5,10,30,45,60];
for ii=1:length(velocity) %Does the this part of the loop 3 times
    velocity_=velocity(ii); %Selects the elements of the velocity vector
    for iii=1:length(angle) %Does this part of the loop 6 times
        angle_=angle(iii); %Selects the elements of the angle vector
        output(ii,iii) = DeLaPena_Trajectory(velocity_,angle_); %Puts the outputs in one matrix, but only the x....
    end   
end 

So, I have this code to calculate the velocity however, the problem with it is output(ii,iii) line of code, it puts just ONE of the outputs into a matrix, I want the [x,y] not just the x. I know the output(ii,iii) is putting the outputs into a matrix, but when I use the anonymous function I always put [x,y]=...... and that gives me both values. Any hints on how I would also get the y value to be able to graph them?

Answer 1

[Stephen23]

You are only calling the function with one output argument. If the function returns two output arguments and you want both of those output arguments then you need to call the function with both output arguments:

[outX(ii,iii),outY(ii,iii)] = DeLaPena_Trajectory(...)

Your code would be more robust if you preallocate the outputs before the loops:

https://www.mathworks.com/help/matlab/matlab_prog/preallocating-arrays.html

For example:

velocity = [30,40,47.16];
angle = [5,7.5,10,30,45,60];
Nv = numel(velocity);
Na = numel(angle);
outX = nan(Nv,Na);
outY = nan(Nv,Na);
for ii=1:Nv
    for jj=1:Na
       [outX(ii,jj),outY(ii,jj)] = DeLaPena_Trajectory(velocity(ii),angle(jj));
    end   
end