how to vectorize this code?

while b < (length(data))

      ECG(i,:) = data(f:b);
      f = f+477;
      b=b+477;
      i= i+1;     

end

[Birdman]

What do you try to do? Is this the entire code?

[Parsa Paiman]

No, this is not the entire code just a part of it. I am reading a BDF file into Matlab. the outcoming datafile has multiple signals in one column. what I want do do is separate the ECG signal from this file. The ECG signal has 400 data point and then 77 point of other data are beneath it, then comes another 400 points of ECG, etc.

Answer 1

[Star Strider]

It appears that your code is segmenting your EKG record into 477-element segments.

The reshape (link) function could likely do this in one call. Assuming that ‘data’ is a row vector, try this:

EKG = reshape(data, [], 477);

The length of ‘data’ must be an integer multiple of 477, so check that first, and trim the length if necessary before the reshape call.

[Parsa Paiman]

I am reading a BDF file into Matlab. the outcoming datafile has multiple signals in one column. what I want do do is separate the ECG signal from this file. The ECG signal has 400 data point and then 77 point of other data are beneath it, then comes another 400 points of ECG, etc.

[Walter Roberson]

Star Strider, you forgot for a moment that MATLAB distributes data down columns first, so your approach would not group the 477 entries together. That is why I reshape to 477 by something and then transpose.

[Star Strider]

Probably the easiest way is to first use rehsape on your column vector, then keep only the first 400 rows:

EKG = reshape(data, 477, []);
EKG = EKG(1:400,:);

You may need to experiment to get the result you want.

[Parsa Paiman]

Thanks Star Strider. This is exactly what I wanted.

[Star Strider]

As always, my pleasure.

Answer 2

[Walter Roberson]

Perhaps

ECG = reshape(data, 477, :).';

[Parsa Paiman]

I am reading a BDF file into Matlab. the outcoming datafile has multiple signals in one column. what I want do do is separate the ECG signal from this file. The ECG signal has 400 data point and then 77 point of other data are beneath it, then comes another 400 points of ECG, etc.