symschur.m

various matlab programs to slove various problems

function [c,s]=symschur(A,p,q)
if (A(p,q)==0)
  c=1; 
  s=0; 
else
  eta=(A(q,q)-A(p,p))/(2*A(p,q));
  if (eta >= 0)
    t=1/(eta+sqrt(1+eta^2));
  else 
    t=-1/(-eta+sqrt(1+eta^2)); 
  end; 
  c=1/sqrt(1+t^2); 
  s=c*t;
end
return