Add vectors in loop

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How would one do something like this simpler? It works but i feel terrible for doing it this way and it takes up heaps of memory i guess
t_er = linspace(1,length(TimeSeries_norm),length(TimeSeries_norm));
ind1 = t_er >= ipts_shift(1) & t_er < ipts_shift(2);
ind2 = t_er >= ipts_shift(3) & t_er < ipts_shift(4);
ind3 = t_er >= ipts_shift(5) & t_er < ipts_shift(6);
ind4 = t_er >= ipts_shift(7) & t_er < ipts_shift(8);
ind5 = t_er >= ipts_shift(9) & t_er < ipts_shift(10);
ind6 = t_er >= ipts_shift(11) & t_er < ipts_shift(12);
ind7 = t_er >= ipts_shift(13) & t_er < ipts_shift(14);
ind8 = t_er >= ipts_shift(15) & t_er < ipts_shift(16);
ind9 = t_er >= ipts_shift(17) & t_er < ipts_shift(18);
ind10 = t_er >= ipts_shift(19) & t_er < ipts_shift(20);
indices = ind1+ind2+ind3+ind4+ind5+ind6+ind7+ind8+ind9+ind10;
TR_er = TimeSeries_norm' .* indices;
  2 Comments
Jørgen Fone Pedersen
Jørgen Fone Pedersen on 1 Mar 2021
Yes, sorry about that. Tried adding the .mat file but its too large.
The Timeseries_norm is just a normalized signal sampled at 1 Mhz. The ipts_shift is the indexes for start and stop in the timeseries for certain events i want to extract.
I multiply indices with timeseries later to zero out all points before index 1 and after index 2, before index 3 and after index 4 etc..
>> whos TimeSeries_norm ipts_shift
Name Size Bytes Class Attributes
TimeSeries_norm 80000000x1 320000000 single
ipts_shift 1x20 160 double
>>

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Accepted Answer

Allen
Allen on 2 Mar 2021
I am certain that there is a much better method using vectorized indexing, but without seeing an example of the values in TimeSeries_norm and ipts_shift, then a for-loop can get the job done fairly efficiently. @darova's method will work in generating an equivalent result for your indices variable, but needs a few corrections to the code in order to do so. Also, be aware that this method assumes that ipts_shift uses an even number of values, and that they are all paired values representing start/stop events.
indices = 0;
for i = 1:2:length(ipts_shift)
indices = indices + (ipts_shift(i)<=t_er & t_er<ipts_shift(i+1));
end
  1 Comment
Jørgen Fone Pedersen
Jørgen Fone Pedersen on 3 Mar 2021
Thank you.
This works perfectly and looks so much better.

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More Answers (1)

darova
darova on 2 Mar 2021
Maybe for loop
ind = 0;
for i = 1:2:length(ipts_shift)
ind1 = ipts_shift(1) <= t_er & t_er < ipts_shift(2);
ind = ind + ind1;
end

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