% TIME_DATA_WORSENER introduces missing points and/or unvenly sampling time% inside time series%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% FUNCTION: time_data_worsener%% DESCRIPTION: TIME_DATA_WORSENER introduces missing points and/or unvenly% sampling times inside time series%% CALL: [t, y] = time_data_worsener(t, y, miss_fraction, shift_fraction, shift_range);%% INPUTS: t vector of evenly sampled time values (in s)% y vector of evenly sampled y values (in arb units)% miss_fraction fraction of the total point to be skipped% shift_fraction fraction of the total point to be shifted% shift_range selection range for shifting the time points (in s) %% OUTPUTS: t vector of unevenly time values% y vector of unevenly sampled y values%% EXAMPLES: [t1,y1] = time_data_worsener(t, y, 0.5, 0, [0 0]);% [t1,y1] = time_data_worsener(t, y, 0, 0.1, [-0.05 0.05]);% [t1,y1] = time_data_worsener(t, y, 0.1, 0.5, [0 0.01]);%% VERSION: $Id: time_data_worsener.m,v 1.1 2009/01/25 16:06:30 mauro Exp $%% HISTORY: 25-01-2009 Hueller% Creation%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%function [t,y] = time_data_worsener(t, y, miss_fraction, shift_fraction, shift_range) % Initial checks if isempty(t) || isempty(y) error('Need to operate on non empty data vectors!') end if length(y) ~= length(t) error('t and y vector should have the same lenghts!'); end if miss_fraction > 1 || miss_fraction < 0 error('Missing points fraction f must fulfil 0 <= f <= 1!'); end if shift_fraction > 1 || shift_fraction < 0 error('Shifted points fraction f must fulfil 0 <= f <= 1!'); end if length(shift_range) < 2 error('Please input the shifting freqency range []'); end %% Remove an amount of points corresponding to the fractional amount input by user % Calculate the orginal data vector length N_points = length(t); % Calculate the number of data points to keep N_keep = round((1 - miss_fraction) * N_points); % Randonmly calculate the index of the data to keep keep_index = sort(randsample(N_points, N_keep)); % Extract the data from time and y vector t = t(keep_index); y = y(keep_index); %% Shift the remaining points by a random amount within the input range N_points = length(t); % Calculate the number of points to shift N_shift = round(shift_fraction * N_points); % Randonmly calculate the index of the data not to shift shift_index = sort(randsample(N_points, N_shift)); % Randomly calculate the delay (positive or negative) and apply it shifts = shift_range(1) + (shift_range(2) - shift_range(1))*rand(N_shift, 1); for kk = 1 : N_shift t(shift_index(kk)) = t(shift_index(kk)) + shifts(kk); endend