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integer function folhp(ls,alpha,beta,s,p)
c Copyright INRIA
integer ls
double precision alpha,beta,s,p
c!purpose
c this routine checks if
c the real root alpha/beta lies in the open left half plane
c (if ls=1)
c the complex conjugate roots with sum s and product p lie
c in the open left half plane (if ls=2)
c if so, folhp=1, otherwise, folhp=-1
c in this function the parameter p is not referenced
c
c!calling sequence
c
c integer function folhp(ls,alpha,beta,s,p)
c integer ls
c double precision alpha,beta,s,p
c!auxiliary routines
c none
c!
folhp=-1
if(ls.eq.2) go to 2
if(alpha*beta.lt.0.0d+0) folhp=1
return
2 if(s.lt.0.0d+0) folhp=1
return
end
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