function [a,b,sig2,iflag] = maynefir(x,n,ip,iq,l,epsilon,nexp) 

iflag=0;
[a sig2] = autocorr(x,n,l);
u = cczflt(x,n,a,l);
[a b iflag] = ls_my(x,u,x,n,ip,iq,epsilon);
if iflag == -1
	return;
end
if iq == 1
	bc(1,1)=b(1);
end

pma=1.;
if iq  > 1
	[bc p0 p] = stepdown(iq,b,pma);
end
for i=1:iq
	if abs(bc(i,i)) >= 1.0
		iflag=1;
		return;
	end
end
y = cpoleflt(x,n,b,iq);
z = cpoleflt(u,n,b,iq);
for i=1:n
	yz(i)=y(i)-z(i);
end
[a b iflag] = ls_my(y,z,yz,n,ip,iq,epsilon);
if iflag == -1
	return;
end
sig2 = varm(x,n,a,ip,b,iq,nexp);