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1 | Copyright 1999, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc. |
2 | Contributed by the AriC and Caramel projects, INRIA. | |
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3 | |
4 | This file is part of the GNU MPFR Library. | |
5 | ||
6 | The GNU MPFR Library is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU Lesser General Public License as published by | |
4a238c70 | 8 | the Free Software Foundation; either version 3 of the License, or (at your |
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9 | option) any later version. |
10 | ||
11 | The GNU MPFR Library is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
13 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public | |
14 | License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
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17 | along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see |
18 | http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., | |
19 | 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. | |
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20 | |
21 | ############################################################################## | |
22 | ||
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23 | Known bugs: |
24 | ||
25 | * The overflow/underflow exceptions may be badly handled in some functions; | |
26 | specially when the intermediary internal results have exponent which | |
27 | exceeds the hardware limit (2^30 for a 32 bits CPU, and 2^62 for a 64 bits | |
28 | CPU) or the exact result is close to an overflow/underflow threshold. | |
29 | ||
30 | * Under Linux/x86 with the traditional FPU, some functions do not work | |
31 | if the FPU rounding precision has been changed to single (this is a | |
32 | bad practice and should be useless, but one never knows what other | |
33 | software will do). | |
34 | ||
35 | * Some functions do not use MPFR_SAVE_EXPO_* macros, thus do not behave | |
36 | correctly in a reduced exponent range. | |
37 | ||
38 | * Function hypot gives incorrect result when on the one hand the difference | |
39 | between parameters' exponents is near 2*MPFR_EMAX_MAX and on the other hand | |
40 | the output precision or the precision of the parameter with greatest | |
41 | absolute value is greater than 2*MPFR_EMAX_MAX-4. | |
42 | ||
43 | Potential bugs: | |
44 | ||
45 | * Possible incorrect results due to internal underflow, which can lead to | |
46 | a huge loss of accuracy while the error analysis doesn't take that into | |
47 | account. If the underflow occurs at the last function call (just before | |
48 | the MPFR_CAN_ROUND), the result should be correct (or MPFR gets into an | |
49 | infinite loop). TODO: check the code and the error analysis. | |
50 | ||
51 | * Possible integer overflows on some machines. | |
52 | ||
53 | * Possible bugs with huge precisions (> 2^30). | |
54 | ||
55 | * Possible bugs if the chosen exponent range does not allow to represent | |
56 | the range [1/16, 16]. | |
57 | ||
58 | * Possible infinite loop in some functions for particular cases: when | |
59 | the exact result is an exactly representable number or the middle of | |
60 | consecutive two such numbers. However for non-algebraic functions, it is | |
61 | believed that no such case exists, except the well-known cases like cos(0)=1, | |
62 | exp(0)=1, and so on, and the x^y function when y is an integer or y=1/2^k. | |
63 | ||
64 | * The mpfr_set_ld function may be quite slow if the long double type has an | |
65 | exponent of more than 15 bits. | |
66 | ||
67 | * mpfr_set_d may give wrong results on some non-IEEE architectures. | |
68 | ||
69 | * Error analysis for some functions may be incorrect (out-of-date due | |
70 | to modifications in the code?). | |
71 | ||
72 | * Possible use of non-portable feature (pre-C99) of the integer division | |
73 | with negative result. |