store data in an array

Along with saying hello, I need help storing information. I did a for loop so that it was storing data, but when dt = [] is not stored, also if you could help me that when it happens that dt = [], the threshold value is 1.5, it would be 0 and thus not have the error that dt was an empty set, in short, that when dt = [], the threshold is 0 so that I can calculate the loop and also store it in the dt matrix.

Thanks greetings.

I attach .txt with the data, a function and the code I leave it copied in the questions panel.

close all, clear all, clc

amplitude=load('amplitude.txt');
x=0:10:4*3600;
threshold = 1.5; 

for j=1:7
        y=amplitude(:,j);
        [val,ind] = max(y);
        x_peak = x(ind);
        [t0_pos,s0_pos,t0_neg,s0_neg]= crossing_V7(y,x,threshold,'linear');
        [minValue, closestIndex1] = min(abs(t0_pos - x_peak));
        closestValue_pos = t0_pos(closestIndex1);
        [minValue, closestIndex2] = min(abs(t0_neg - x_peak));
        closestValue_neg = t0_neg(closestIndex2);
        dt = abs(closestValue_neg - closestValue_pos)./60
end

Answer 1

[Walter Roberson]

amplitude=load('amplitude.txt');
x=0:10:4*3600;
threshold = 1.5; 

cols = size(amplitude,2);
all_dt = zeros(1,cols);

for j=1:cols
        y=amplitude(:,j);
        [val,ind] = max(y);
        x_peak = x(ind);
        [t0_pos,s0_pos,t0_neg,s0_neg]= crossing_V7(y,x,threshold,'linear');
        [minValue, closestIndex1] = min(abs(t0_pos - x_peak));
        closestValue_pos = t0_pos(closestIndex1);
        [minValue, closestIndex2] = min(abs(t0_neg - x_peak));
        closestValue_neg = t0_neg(closestIndex2);
        dt = abs(closestValue_neg - closestValue_pos)./60;
        if isempty(dt); dt = 0; end
        all_dt(j) = dt;
end

[ibt]

@Walter Roberson

Thanks, I want to see how it could be added to the code that you. attached, that if the maximum peak is greater than 5 the threshold value is 2 and that the value is executed and saved in dt, and in the case that it is less than this value that the threshold is 0.

[Walter Roberson]

I am not sure which value is the maximum peak?

amplitude=load('amplitude.txt');
x=0:10:4*3600;

cols = size(amplitude,2);
all_dt = zeros(1,cols);

for j=1:cols
        y=amplitude(:,j);
        [val,ind] = max(y);
        if val > 5
           localthresh = 2;
        else
            localthresh = 0;
        end
        x_peak = x(ind);
        [t0_pos,s0_pos,t0_neg,s0_neg]= crossing_V7(y,x,localthresh,'linear');
        [minValue, closestIndex1] = min(abs(t0_pos - x_peak));
        closestValue_pos = t0_pos(closestIndex1);
        [minValue, closestIndex2] = min(abs(t0_neg - x_peak));
        closestValue_neg = t0_neg(closestIndex2);
        dt = abs(closestValue_neg - closestValue_pos)./60;
        if isempty(dt); dt = 0; end
        all_dt(j) = dt;
end

[ibt]

It executes the code, but I get an empty set in the results of the code.

[Walter Roberson]

The only way that code can return empty is if the loaded amplitude is empty. In such a case,, cols would come out as 0 and all_dt would be a 1 x 0 matrix.

In all other cases, the result in all_dt could potentially turn out all 0, but cannot turn out empty.