set style line 2 lc rgb '#dd181f' lt 1 lw 2 pt 5 ps 1.5 # --- red
plot'log_exp_Sparse.txt' index 0 using 1:4 t "No log exp" with linespoints ls 2,\
'log_exp_Sparse.txt' index 0 using 1:2 t "with log exp" with linespoints ls 1,\
set style line 2 lc rgb '#dd181f' lt 1 lw 2 pt 5 ps 1.5 # --- red
plot'log_exp_Sparse.txt' index 0 using 1:4 t "No log exp" with linespoints ls 2,\
'log_exp_Sparse.txt' index 0 using 1:2 t "with log exp" with linespoints ls 1,\