Plotting Average curve for points in gnuplot

Question

[Current]

I am importing a text file in which the first column has simulation time (0~150) the second column has the delay (0.01~0.02).

1.000000 0.01         


        

Answer 1

For gnuplot >=5.2, probably the most efficient solution is using an array like @Franky_GT's solution. However, it uses the pseudocolumn 0 (see help pseudocolumns). In case you have some empty lines in your data $0 will be reset to 0 which eventually might mess up your average.

This solution uses an index t to count up the datalines and a second array X[] in case a centered moving average is desired. Datapoints don't have to be equidistant in x. At the beginning there will not be enough datapoints for a centered average of N points so for the x-value it will use every second point and the other will be NaN, that's why set datafile missing NaN is necessary to plot a connected line at the beginning.

Code:

### moving average over N points
reset session

# create some test data
set print $Data
    y = 0
    do for [i=1:5000] {
        print sprintf("%g %g", i, y=y+rand(0)*2-1) 
    }
set print

# average over N values
N = 250
array Avg[N]
array X[N]

MovAvg(col) = (Avg[(t-1)%N+1]=column(col), n = t

Result: