#
#  Kink-Kink soln to the sine-gordon eq,
#
set dummy x,t;
c1 = 1.5; c2 = 0.9;

e1(x,t)= exp(c1*x - 1./c1 *t);
e2(x,t)= exp(c2*x - 1./c2 *t);
e12(x,t) = e1(x,t)*e2(x,t);
f(x,t) = (c1-c2)*(1+e12(x,t));
g(x,t) = (c1+c2)*(e1(x,t)-e2(x,t));
func(x,t) = 4.0* atan(g(x,t)/f(x,t));

a=sur{[func(x,t)][x=-25,25][t=-25,25]};
plot a;
