Hi, 1) I am getting signaling due to division by 0. The following lines are faulty: mpfr_float p("1.1"); mpq_rational q(p); signal: integer divide by zero; whereas this succeeds: mpq_rational q(1.1); any one seen this before? i'm on compiler Apple LLVM version 8.0.0 (clang-800.0.38) ,with homebrew-provided boost 1.64, mpfr 3.1.5, gmp 6.1.2. -- 2) I also expected to be able to construct rationals as mpq_rational q("1.1") but it fails to parse using the built-in constructor. i mean, i understand why (1.1 isn't a rational), but given that i can construct a rational from a double, i figured that i'd get something reasonable from "1.1", namely 11/10. -- thanks! dani brake university of wisconsin eau claire ps i am not disabling mixed double-multiprecision arithmetic in this scenario, in case you have been reading my other questions this last week