Need a fast way to create a counter variable

Question

Darin McCoy 2013-2-15

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/63655-need-a-fast-way-to-create-a-counter-variable

I'm trying to find a faster way to calculate the time a time series data set is at a particular value. Here is my code (but i KNOW theres gotta be a better way to do this? using diff maybe?) Any ideas on how to make this faster? I need help in the middle section (not the initialization or the plotting)

%Create a sample set of data
time = 0:.12:(.12*10000 - .12);
data = zeros(10000,1);
data(2:100,1) = 1;
data(400:500,1) = 1;
value = 0;
timestep = 0.12;
%%This part will look at time series data and create a variable showing how long the variable has been active
%Initialize
currently_counting = 0;
counter_channel = zeros(size(data));
data_meets_conditions = find(data==value);
%For all of the data
for i = 1:size(data_meets_conditions,1)
      %Current index of the data channel that you are going through...
      cur_data_index = data_meets_conditions(i);
      if currently_counting == 1;
          %Use the last counter channel and add a time value to it.
          counter_channel(cur_data_index) = counter_channel(cur_data_index-1) + timestep;
      end
      %Used for the very first case
      min_index = max(1,cur_data_index-1);
      if data(cur_data_index) == data(min_index)
          %Start counting
          currently_counting = 1;
      else
          currently_counting = 0;
      end
  end
%%Plotting
figure
subplot(2,1,1);
plot(time,data)
subplot(2,1,2);
plot(time,counter_channel)