loss of data/missing elements in array after a for loop

Hello everyone,

I experienced a loss of data when comparing my input and ouput matrices.

for ch=1:32
          TD_32_denoise_post_single_chan = TD_32_colon(:,ch);
          [val_rms, idx_rms] = findpeaks(-TD_32_denoise_post_single_chan', ...
    MinPeakHeight=mat_thr_filt_dat(ch));
          idx_matrix_bool_mat_filt(idx_rms,ch) = true;
end

TD_32_colon is a 2584386x32 matrix

idx_matrix_bool_mat_filt is a 2584128x32 matrix

the total loss of data points is 258x32

I do not know where these points are located, and this issue prevents me from performing any operation as I get weird results.

Do you have any suggestion?

Answer 1

[Fangjun Jiang]

If you don't pre-allocate idx_matrix_bool_mat_filt, this could happen. Do idx_matrix_bool_mat_filt=TD_32_colon before the loop.

clear c
a=rand(1,10);
index=find(a>0.5);
c(index)=true

c = 1×5 logical array
   0   0   1   0   1

[Enzo]

it worked smoothly. Thanks for your help. Really appreciated