The error generated by the compiler was:
no matching function for call to 'maxi'
RealScalar threshold = numext::maxi(tol*tol*rhsNorm2,considerAsZero);
The important part in the following notes was:
candidate template ignored: deduced conflicting
types for parameter 'T'"
('codi::Multiply11<...>' vs. 'codi::ActiveReal<...>')
EIGEN_ALWAYS_INLINE T maxi(const T& x, const T& y)
I am using CoDiPack to provide the RealScalar type.
This bug was introduced in bc000deaa Fix conjugate-gradient for very small rhs