How to execute statements within functions in a random order?

'm relatively new to Matlab, and I've been trying to solve my problem for ages but I'm just continuously arriving at a dead end.

I have a code which should, in theory, play 3 sounds in a random order (each order being different for each trial). Upon each sound playing the participant will be asked which sound they heard and then given feedback. I have all the code complete and working up until the random order part. I have created code that on each trial will randomly order 1,2 and 3.

 Order = [1, 2, 3];
 PhonemeOrder = randperm (numel(Order));

I then have a function which plays the sound/asks the questions etc. within this I have attempted switch cases statements and if else statements depending on the number that PhonemeOrder produces but the order doesnt change even when phoneme order does. I believe my problem is however that PhonemeOrder comes out like [1,2,3] or [3,1,2] which is what i wanted. but Im not sure how to get my sounds to play in the order that it shows because I am using code like...

 if/ PhonemeOrder = 1;
      then do this...
  elseif phonemeorder = 2; 
     then do this...
  else 
    do this...

Or I've tried code like

 switch cases 
    case 1 
       do this 
    case 2 
       do this 
    case 3 
      do this

I'm guessing this is where i am going wrong, but i just dont know how to change it and make it work! I hope this makes sense? I just need it to play in the order that phonemeorder specifies, with the order changing on each trial.

It's probably a really simple solution but the continuous errors and the amount of hours I've tried changing it has finally made me ask! Any help will be greatly appreciated :D

[David Young]

It is possible to do what you want using (for example) an array of function handles - but there may be a simpler way, by reordering the elements of a cell or struct array of sound recordings. Can you give an example of the code that actually generates the sound?

Answer 1

[Guillaume]

The way I would do this:

sounds = {'ba.wav', 'da.wav', 'ga.wav', 'fa.wav'}; %or whatever you want
numtrials = 2; %or whatever you want

%reorder numtrials * sounds in a random permutation: 
orderedidx = repmat(1:numel(sounds), 1, numtrials);
p = randperm(numtrials * numel(sounds));
randsounds = sounds(orderedidx(p));

%play the sounds in the random order:
for sound = randsounds
    sound = sound{1};
    [fs, y] = audioread(sound);
    %... rest of the code
end

Answer 2

[Sean de Wolski]

phoneorder = randperm(3);

for ii = 1:numel(phoneorder)
    disp(phoneorder(ii))
    switch phoneorder(ii)
        % Play AC/DC at various different sample rates
        case 1            
            sound(rand(10000,1),16000)            
        case 2            
            sound(rand(10000,1),3000)
        case 3            
            sound(rand(10000,1),50000)

      end
  end

Answer 3

[David Young]

One possible structure - but see my comment above.

for trial = 1:3
  switch phonemeorder(trial)
    case 1
       < code for first sound >
    case 2
       < code for second sound >
    case 3
       < code for third sound >
   end
end

[Bex G]

Hi David thanks for the help this worked. but I can show you an example of my sound code as you asked in the above comment

[fs,y] = audioread('ba.wav'); noisySound = fs+ 0.01 * randn(length(fs), 1); soundsc(noisySound, freq);

the only problem I have now is that because for trial = 1:3. it is only executing my code three times which is fine if i want 1 trial of each sound (3 sounds in total) but if I want 2 trials of each (so 6 sounds playing) then it will only execute 3 and then give me output. I've tried doing 1:data.experimentdata.nTrials

but it just doesn't work

[Sean de Wolski]

Bex, you can use mod to do this for you:

nrep = 2;
phoneorder = mod(randperm(3*nrep),3)+1

[Bex G]

awesome thankyou both so much :D Now I just need to work out how to save all the response on each trial...

Thanks again guys, big help!

[David Young]

Just a belated note to say that the better solution is that given by Guillaume, which simply rearranges the contents of a cell array.