# set terminal svg size 600,400 dynamic enhanced fname 'arial' fsize 10 mousing name "vector_1" butt solid # set output 'vector.1.svg' set label 1 "-q" at -1, 0, 0 centre norotate back nopoint offset character 0, 0, 0 set label 2 "+q" at 1, 0, 0 centre norotate back nopoint offset character 0, 0, 0 set view map set isosamples 31, 31 unset surface set contour base set cntrparam levels discrete -3,-2 ,-1 ,-0.5 ,-0.2 ,-0.1 ,-0.05 ,-0.02 ,0 ,0.02 ,0.05 ,0.1 ,0.2 ,0.5 ,1 ,2 ,3 set rrange [ 0.00000 : 10.0000 ] noreverse nowriteback set trange [ -5.00000 : 5.00000 ] noreverse nowriteback set urange [ -5.00000 : 5.00000 ] noreverse nowriteback set vrange [ -5.00000 : 5.00000 ] noreverse nowriteback set xrange [ -10.0000 : 10.0000 ] noreverse nowriteback set x2range [ -10.0000 : 10.0000 ] noreverse nowriteback set yrange [ -10.0000 : 10.0000 ] noreverse nowriteback set y2range [ -10.0000 : 10.0000 ] noreverse nowriteback set zrange [ -10.0000 : 10.0000 ] noreverse nowriteback set cbrange [ -10.0000 : 10.0000 ] noreverse nowriteback r(x,y)=sqrt(x*x+y*y) v1(x,y)= q1/(r((x-x0),y)) v2(x,y)= q2/(r((x+x0),y)) vtot(x,y)=v1(x,y)+v2(x,y) e1x(x,y)= q1*(x-x0)/r(x-x0,y)**3 e1y(x,y)= q1*(y)/r(x-x0,y)**3 e2x(x,y)= q2*(x+x0)/r(x+x0,y)**3 e2y(x,y)= q2*(y)/r(x+x0,y)**3 etotx(x,y)=e1x(x,y)+e2x(x,y) etoty(x,y)=e1y(x,y)+e2y(x,y) enorm(x,y)=sqrt(etotx(x,y)*etotx(x,y)+etoty(x,y)*etoty(x,y)) dx1(x,y)=coef*etotx(x,y)/enorm(x,y) dy1(x,y)=coef*etoty(x,y)/enorm(x,y) dx2(x,y)=coef*etotx(x,y) dy2(x,y)=coef*etoty(x,y) GPFUN_r = "r(x,y)=sqrt(x*x+y*y)" q1 = 1 x0 = 1.0 GPFUN_v1 = "v1(x,y)= q1/(r((x-x0),y))" q2 = -1 GPFUN_v2 = "v2(x,y)= q2/(r((x+x0),y))" GPFUN_vtot = "vtot(x,y)=v1(x,y)+v2(x,y)" GPFUN_e1x = "e1x(x,y)= q1*(x-x0)/r(x-x0,y)**3" GPFUN_e1y = "e1y(x,y)= q1*(y)/r(x-x0,y)**3" GPFUN_e2x = "e2x(x,y)= q2*(x+x0)/r(x+x0,y)**3" GPFUN_e2y = "e2y(x,y)= q2*(y)/r(x+x0,y)**3" GPFUN_etotx = "etotx(x,y)=e1x(x,y)+e2x(x,y)" GPFUN_etoty = "etoty(x,y)=e1y(x,y)+e2y(x,y)" GPFUN_enorm = "enorm(x,y)=sqrt(etotx(x,y)*etotx(x,y)+etoty(x,y)*etoty(x,y))" coef = 0.7 GPFUN_dx1 = "dx1(x,y)=coef*etotx(x,y)/enorm(x,y)" GPFUN_dy1 = "dy1(x,y)=coef*etoty(x,y)/enorm(x,y)" GPFUN_dx2 = "dx2(x,y)=coef*etotx(x,y)" GPFUN_dy2 = "dy2(x,y)=coef*etoty(x,y)" xmin = -10.0 xmax = 10.0 ymin = -10.0 ymax = 10.0 splot vtot(x,y) w l