MATLAB: Assigning randomized values (of a linspace range using randperm) to an empty vector for posterior graphing

neurosciencetimingvectors

Hello, The following code plays two beeps with a pause between them. The pause may vary within a range defined by linspace. Then randperm, randomizes the pauses. What 'c' does is combine both the functions mentioned before, in some sort of indexing device (pardon my novice-ness). When the programme ends, c displays the last randomized duration value of the range .
What I need is to graph all the user's inputs in a graph that compares them with the duration values. The problem is that when 'c' is plotted, it only shows the last duration value, as a small point in the graph.
The thing is supposed to measure the user's timing perception based on the comparison of his inputs and the duration values. It is a neuroscience experiment.
Code:
Fs=8192;                      %sample rate
y=sin(2*pi*2000*[0:1/Fs:0.5]);  %sinewave; rate
a=linspace(0.5,1,5);            %pause durations
for b=randperm(5) 
c=a(b)                          %pause's randomization by permutation
sound(y,Fs), pause(c), sound(y,Fs), %sound production
pause,tic, pause, toc           %user input; timing measures  
end
I hope I was clear enough. Thanks

Best Answer

I have modified your code, see if this is what you are after:
clc;clear  
Fs=8192;                      %sample rate
y=sin(2*pi*2000*[0:1/Fs:0.5]);  %sinewave; rate
a=linspace(0.5,1,5);            %pause durations
k = 0;
for b=randperm(5)
    k = k+1;                  % counter
    c(k) = a(b);              %pause's randomization by permutation
    sound(y,Fs), pause(c(k)), sound(y,Fs), %sound production
    pause
    tic
    pause
    p(k)= toc;           % user input; timing measures
    pause                % extra pause to ensure subject is ready
end
plot(c,p,'bo',c,c,'g-')
xlim([.4 1.1])
ylim([.4 1.1])
xlabel('actual')
ylabel('percieved')
legend('response','ideal',2)
r = corrcoef(c,p);
text(.95,.6 ,num2str(r(2)))
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