How to create a matlab function?

Hi, I'm trying to create my own matlab function, but I don't really understand the way it works;

Here is what I have:

function [Y] = CalibratieABP(ABP)
%UNTITLED5 Summary of this function goes here
%   Detailed explanation goes here

      afstand = 4;  %over hoe lang je het gemiddelde neemt
      k = 4;  %onder en bovengrens 
      lengte=25;  %lengte hoelang achter elkaar +- 0 
  %%ABP
  p = ABP;     %ABP of CVP? ook aanpassen in titel
  % gemiddelde stukje nemen
  mean = movmean(p,afstand);
  Y1 = mean<k;
  Y2 = mean>-k;
  Yy = Y1.*Y2;
  %minimaal aantal opeenvolgende 1
  Y = zeros(size(p));
  locations = strfind([Yy'], ones(1,lengte));
  for i=1:lengte
      Y([locations+i-1]) = 1;
  end
  end

the %adds some extra information.

I know that i'm doing something something wrong with the function at the beginning, but I don't see what it should be like.

I want ABP as input and Y as output.

Thanks!

Answer 1

[Wilson A N]

The format in your script is correct for ABP as input and Y as output. Also, when creating your own MATLAB function you need to save the function .m file with the same name as the function. In your case the function .m file should be named as 'CalibratieABP.m'. For more information just check the documentation given below: https://www.mathworks.com/help/matlab/ref/function.html

I tried the above script and called the MATLAB function as

>> a = Calibratie(10);

from the MATLAB command line. This is working for me.

[Guillaume]

Yes, it's not clear what Tessa is having as the function works fine as it is.

The code could do with some improvements though. For a start what is the point of renaming ABP into p. Just use the variable ABP in the code. Calling a variable mean is not a good idea since it shadows the mean function. And while .* works for computing the AND of two logical vectors, & is a lot clearer. In any case, testing the bounds of the mean can all be done in one line. Finally, if you have R2016b, you can use implicit expansion to remove the loop. So:

function [Y] = CalibratieABP(ABP)
   %UNTITLED5 Summary of this function goes here
   %Detailed explanation goes here
  validateattributes(ABP, {'numeric'}, {'column'});  %assumptions that were built into the original code 
  afstand = 4;  %over hoe lang je het gemiddelde neemt
  k = 4;  %onder en bovengrens 
  lengte=25;  %lengte hoelang achter elkaar +- 0 
  p = ABP;     %ABP of CVP? ook aanpassen in titel
  % gemiddelde stukje nemen
  haslowmean = abs(movmean(ABP, afstand)) < k;
  locations = strfind(haslowmean.', ones(1,lengte));
  Y = zeros(size(ABP))
  Y([locations+(0:lengte-1)']) = 1;
end

[Image Analyst]

Maybe she's not calling it and passing it data. Maybe she's just hitting F5 or clicking the green run triangle. Who knows? Only Tessa, because she didn't tell us what the problem was, like pasting ALL the red text from an error message, or giving us the output data and saying why it's not right, or something.