Add vectors in loop

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;

[Allen]

Jorgen,

Can you provide an example of the TimeSeries_norm and ipts_shift variables you are working with or preferably at least array dimensions/sizes?

[Jørgen Fone Pedersen]

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              

>> 

Answer 1

[Allen]

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

[Jørgen Fone Pedersen]

Thank you.

This works perfectly and looks so much better.

Answer 2

[darova]

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