2D Wave Equation [gnuplot]-Hiro's Soliloquy

Contents[hide]

Source code [gnuplot]


	reset

	#=================== Parameters ====================
	t = 0. # Time
	dt = 0.005 # Time step [s]
	N = 20 # sum[i,j=1:N]

	nu = 1. # Coefficient
	n_max = 1000 # Loop limit (Time limit: n_max*dt)
	n = 0 # Counter (initialized)
	cut = 10 # Decimation (frame: n_max/cut)

	#=================== Functions ====================
	u(x, y, t) = 16/(pi*6)sum[i=1:N](sum[j=1:N]\
	(1-(-1)*i)(1-(-1)*j)sin(ipix)sin(jpiy)cos(nusqrt(i2+j2)pi*t)\
	/(ij)*3)

	#=================== Setting ====================
	set terminal gif delay 4 animate size 1280, 720
	set output "wave equation.gif"
	set tics font 'Times,18'
	set nokey
	set grid
	set xr[0:1]
	set yr[0:1]
	set zr[-0.08:0.08]
	set xl "x" font"Times:Italic, 22"
	set yl "y" font"Times:Italic, 22"
	set zl "u" font"Times:Italic, 22"
	set view 40, 30, 0.85, 2.
	set pm3d
	set cbrange[-0.08:0.08]
	set palette defined ( 0 '#000090',1 '#000fff',2 '#0090ff',3 '#0fffee',\
	4 '#90ff70',5 '#ffee00',6 '#ff7000',7 '#ee0000',8 '#7f0000')

	call "make_gif.plt"

view raw wave_eq_gif.plt hosted with ❤ by GitHub

	# Loop
	if(n%cut==0){
	time = sprintf("{/Times:Italic t} = %4.2f",t)
	set title time font 'Times,18'
	splot u(x, y, t) lc -1
	}
	t = t + dt # update t
	n = n + 1 # update n

	if(n <= n_max) reread

	set out