timeElapsed.m

function newArray = timeElapsed(datetime_array)
% This function converts an array of elements in datetime format
% into the total elapsed time in seconds since the first data point was
% acquired
%
% To find out more about datetime formats and arrays try the command:
%
%   >> doc datetime
%
% Copyright 2018 The MathWorks, Inc

newArray = second(datetime_array);
arraySize = numel(newArray); %Number of elements in the array
first = newArray(1);
i = 1;

% The following loop will run until it reaches the end of the array.
% Whenever the next number is smaller than the current number the loop will
% add 60 seconds and then start at the begining of the array again.
while i < arraySize
    if newArray(i) > newArray(i+1)
        newArray(i+1) = newArray(i+1) +60;
        i = 1;
    end
    i = i+1;
end

% Subtract the first number to all elements of the array in order to start
% the array at 0.
    newArray = newArray - first;  

end