global a


a  = 0.3;
v = -0.15:0.01:1.1;
t = 0;
dvdt = potential_eqn(t,v);
figure(1);plot(v,dvdt)
xlabel('v')
ylabel('dv / dt')
options = odeset('RelTol',1e-4,'AbsTol',[1e-4]);

t0 = 0;
tfinal = 10;


v_ini = 0.1:0.1:1.1;

nn = length(v_ini);

for ind = 1:nn

y_ini = v_ini(ind);

[T,y] = ode45(@potential_eqn,[t0 tfinal],y_ini,options);

figure(2);hold on;plot(T,y); xlabel('t'); ylabel('v')
end