Combining 3 curves into 1 average

Hi, I am trying to combine 3 curves into 1 average curve (by taking the mean of the 3 curves). As far as I understand (by reading other questions on this site) I need to use interp1, but I am not sure how to create the 'query points' (that I called n). So far my code looks like this:

n = linspace(???);

yyS = interp1(timeS(:),Y2S(:),n);
yyC = interp1(timeC(:),Y2C(:),n);
yyA = interp1(timeA(:),Y2A(:),n);

avg = mean([yyS, yyC, yyA],3);

figure(10);
plot(avg)

The data has the following dimensions:

timeS & Y2S: 345x1

timeC & Y2C: 336x1

timeA & Y2A: 335x1

Any help would be greatly appreciated!!

Answer 1

[Ameer Hamza]

Create 'n' like this

min_n = min([timeS; timeC; timeA])
max_n = max([timeS; timeC; timeA])
n = linspace(min_n, max_n, 300).'; % choose any appropriate number instead of 300

yyS = interp1(timeS(:),Y2S(:),n);
yyC = interp1(timeC(:),Y2C(:),n);
yyA = interp1(timeA(:),Y2A(:),n);

avg = mean([yyS, yyC, yyA], 2); % second input should be 2 (not 3)

figure(10);
plot(n, avg)

[H Lange]

How do I know which number to use? I tried running your code but the plot still doesn't show up...

[Ameer Hamza]

These lines will extract minimum and maximum numbers from 3 vectors and then create a new vector using those values.

Can you attach the variables in a .mat file?

[H Lange]

I've never made a .mat file before, so I hope I did this right :)

[Ameer Hamza]

Yes, the .mat file is correct. There was a little type in my answer. Run the updated answer now.

[H Lange]

Thank you so much!!

[Ameer Hamza]

I am glad to be of help!

Answer 2

[Stephan]

Here is a simple example:

% fantasy times
times1 = 1:10
times2 = 1:2:11

% fantasy values
y1 = 2 * (1:10)
y2 = 4 * (1:2:11)

% interpolate, query points should be longest time frame
y2_new = interp1(times2,y2,times1)

% Concatenate the vectors to calculate the mean for every pair
y_all = [y1; y2_new];

% get the mean
y_mean = mean(y_all)

[H Lange]

I'm not sure I know how to apply this example to my code. I tried the following, but that doesn't seem to work..

yyS = interp1(timeS,Y2S,timeS);
yyC = interp1(timeC,Y2C,timeS);
yyA = interp1(timeA,Y2A,timeS);

yS = [Y2S; yyS];

yC = [Y2S; yyC];

yA = [Y2S; yyA];

avg = mean([yS,yC,yA]);

[Stephan]

It is a simple example that you can walk through to understand what happens. I think understanding the way it works and the transfer this knowledge on your problem is easier on the long term than just copy and paste something, that you do not understand.