id summary reporter owner description type status milestone component version severity resolution keywords cc 4847 tweaking the memoized fibonnacci to produce > 40 number give strange results sylvain foubert Joaquín M López Muñoz "I changed the integer type for numbers from int to unsigned long for higher precision and I got erroneous computed values after F(47) : F(46)=1836311903 F(47)=2971215073 F(48)=512559680 F(49)=3483774753 {{{ typedef flyweight,no_tracking> fibonacci; struct compute_fibonacci:private boost::noncopyable { compute_fibonacci(unsigned long n): result(n==0?0:n==1?1:fibonacci(n-2).get()+fibonacci(n-1).get()) {} operator unsigned long()const{return result;} unsigned long result; }; }}} Internal bug or unprecautious use of the API ?" Bugs closed To Be Determined flyweight Boost 1.44.0 Problem invalid example fibonacci