set style line 2 lc rgb '#dd181f' lt 1 lw 2 pt 5 ps 1.5 # --- red
plot 'influence_nb_threads.txt' using 1:2 t "sparse 500K" with linespoints ls 1,\
'influence_nb_threads.txt' using 1:4 t "full 500K" with linespoints ls 2,\
set style line 2 lc rgb '#dd181f' lt 1 lw 2 pt 5 ps 1.5 # --- red
plot 'influence_nb_threads.txt' using 1:2 t "sparse 500K" with linespoints ls 1,\
'influence_nb_threads.txt' using 1:4 t "full 500K" with linespoints ls 2,\