gnuplot xvalue of maximum of y

Question

I have a file made of three columns, x, y1 and y2. I need to know the value at which y2 has a maximum. To find the maximum of y2 is easy:

stats 'test2-EDB.dat' u 3

from which I know that the y2 has a maximum on the 6779th line of the file

STATS_index_max = 6779.0

However, what I need it the x value at the 6779th line of the file. Do you have any suggestions? Which optimally are platform independent?

The solution which I have found here (Reading dataset value into a gnuplot variable (start of X series)) was:

at(file, row, col) = system( sprintf("awk -v row=%d -v col=%d 'NR == row {print $col}' %s", row, col, file) )
file="test2-EDB.dat" ; row=STATS_index_max ; col=1
c=at(file,row,col)

However, I doubt that this solutions works without any problems also on windows (no idea, I'm not using it).

With best regards, Leonardo

Answer 1

You can use every for the stats command to get the x-value:

stats 'test2-EDB.dat' u 3
stats 'test2-EDB.dat' u 1 every ::STATS_index_max::STATS_index_max
print sprintf("x-value is %e", STATS_max)