1Copyright 1999, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. 2Contributed by the Arenaire and Cacao projects, INRIA. 3 4This file is part of the GNU MPFR Library. 5 6The GNU MPFR Library is free software; you can redistribute it and/or modify 7it under the terms of the GNU Lesser General Public License as published by 8the Free Software Foundation; either version 2.1 of the License, or (at your 9option) any later version. 10 11The GNU MPFR Library is distributed in the hope that it will be useful, but 12WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 13or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 14License for more details. 15 16You should have received a copy of the GNU Lesser General Public License 17along with the GNU MPFR Library; see the file COPYING.LIB. If not, write to 18the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, 19MA 02110-1301, USA. 20 21############################################################################## 22 23Probably many bugs. 24 25Known bugs: 26 27* The overflow/underflow exceptions may be badly handled in some functions; 28 specially when the intermediary internal results have exponent which 29 exceeds the hardware limit (2^30 for a 32 bits CPU, and 2^62 for a 64 bits 30 CPU) or the exact result is close to an overflow/underflow threshold. 31 32* Under Linux/x86 with the traditional FPU, some functions do not work 33 if the FPU rounding precision has been changed to single (this is a 34 bad practice and should be useless, but one never knows what other 35 software will do). 36 37* Some functions do not use MPFR_SAVE_EXPO_* macros, thus do not behave 38 correctly in a reduced exponent range. 39 40* Function hypot gives incorrect result when on the one hand the difference 41 between parameters' exponents is near 2*MPFR_EMAX_MAX and on the other hand 42 the output precision or the precision of the parameter with greatest 43 absolute value is greater than 2*MPFR_EMAX_MAX-4. 44 45Potential bugs: 46 47* Possible incorrect results due to internal underflow, which can lead to 48 a huge loss of accuracy while the error analysis doesn't take that into 49 account. If the underflow occurs at the last function call (just before 50 the MPFR_CAN_ROUND), the result should be correct (or MPFR gets into an 51 infinite loop). TODO: check the code and the error analysis. 52 53* Possible integer overflows on some machines. 54 55* Possible bugs with huge precisions (> 2^30). 56 57* Possible bugs if the chosen exponent range does not allow to represent 58 the range [1/16, 16]. 59 60* Possible infinite loop in some functions for particular cases: when 61 the exact result is an exactly representable number or the middle of 62 consecutive two such numbers. However for non-algebraic functions, it is 63 believed that no such case exists, except the well-known cases like cos(0)=1, 64 exp(0)=1, and so on, and the x^y function when y is an integer or y=1/2^k. 65 66* The mpfr_set_ld function may be quite slow if the long double type has an 67 exponent of more than 15 bits. 68 69* mpfr_set_d may give wrong results on some non-IEEE architectures. 70 71* Error analysis for some functions may be incorrect (out-of-date due 72 to modifications in the code?). 73 74* Possible use of non-portable feature (pre-C99) of the integer division 75 with negative result. 76