Gnuplot tips

Simple animation

This example shows how to directly pipe data to gnuplot to get an animation.

      program main
      implicit none

      integer it, i, np
      real*8  t, dt, dx, x, PI
      parameter(PI=4.0d0*datan(1.0d0))

      dt = 0.1d0
      t  = 0.0d0
      np = 100
      dx = 1.0d0/(np-1)

      do it=1,100
         t = t + dt
         print*,"set title 'Iter=",it,"  Time =",t,"'"
         print*,"set xlabel 'x'"
         print*,"set ylabel 'f'"
         print*,"plot [0:1][-1.1:1.1] '-' w l lw 2"
         do i=1,np
            x = (i-1)*dx - t
            print*,(i-1)*dx,dsin(2.0d0*PI*x)
         enddo
         print*,"e"
         print*,"pause 0.2"
      enddo

      stop
      end

Compile the fortran program and run it as follows

gfortran anim.f
./a.out | gnuplot

Animate solution from files

Plot by naming files

set style data lines
do for [i=0:6] { plot sprintf('sol-%04d.gnu', i) using 1:2; pause 0.5 }

Plot automatically all files which match some pattern

set style data lines
do for [f in system("ls sol-*.gnu")] { 
    plot f using 1:2
    pause 0.5 
}

Setting fonts

set term qt font "Helvetica,30"  # Changes all fonts
set title   font "Helvetica,30"
set tics    font "Helvetica,30"
set xtics   font "Helvetica,30"
set ytics   font "Helvetica,30"
set label   font "Helvetica,30"
set xlabel  font "Helvetica,30"
set ylabel  font "Helvetica,30"
set key     font "Helvetica,30"