function [tBreak,a,b,c,m,p]=essential_distMinAnglePair_discontinuityDistance(Q21)
a=Q21(1,1)+Q21(2,2);
b=Q21(1,2)-Q21(2,1);
c=Q21(3,3);

m=norm([a;b]);
p=sign(a)*acos(clip(b/m));

%tBreak=modAngle(3/2*pi-p);
tBreak=-0.5*pi-p;

function v=clip(v)
v=min(1,max(-1,v));
