299c6f0c6b
Changes from version 4.0.0 to version 4.0.1: - Bug fixes (see ChangeLog file), in particular in mpfr_div_ui, which could yield an incorrectly rounded result to nearest when using different precisions; this bug had been present since the introduction of mpfr_div_ui, and in MPFR 4.0.0, it was affecting mpfr_div too. Changes from versions 3.1.* to version 4.0.0: - Partial support of MPFR_RNDF (faithful rounding). - New functions: mpfr_fpif_export and mpfr_fpif_import to export and import numbers in a floating-point interchange format, independent both on the number of bits per word and on the endianness. - New function mpfr_fmodquo to return the low bits of the quotient corresponding to mpfr_fmod. - New functions mpfr_flags_clear, mpfr_flags_set, mpfr_flags_test, mpfr_flags_save and mpfr_flags_restore to operate on groups of flags. - New functions mpfr_set_float128 and mpfr_get_float128 to convert from/to the __float128 type (requires --enable-float128 and compiler support). - New functions mpfr_buildopt_float128_p and mpfr_buildopt_sharedcache_p. - New functions mpfr_rint_roundeven and mpfr_roundeven, completing the other similar round-to-integer functions for rounding to nearest with the even-rounding rule. - New macro mpfr_round_nearest_away to add partial emulation of the rounding to nearest-away (as defined in IEEE 754-2008). - New functions mpfr_nrandom and mpfr_erandom to generate random numbers following normal and exponential distributions respectively. - New functions mpfr_fmma and mpfr_fmms to compute a*b+c*d and a*b-c*d. - New function mpfr_rootn_ui, similar to mpfr_root, but agreeing with the rootn function of the IEEE 754-2008 standard. - New functions mpfr_log_ui to compute the logarithm of an integer, mpfr_gamma_inc for the incomplete Gamma function. - New function mpfr_beta for the Beta function (incomplete, experimental). - New function mpfr_get_q to convert a floating-point number into rational. - Dropped K&R C compatibility. - Major speedup in mpfr_add, mpfr_sub, mpfr_mul, mpfr_div and mpfr_sqrt when all operands have the same precision and this precision is less than twice the number of bits per word, e.g., less than 128 on a 64-bit computer. - Speedup by a factor of almost 2 in the double <--> mpfr conversions (mpfr_set_d and mpfr_get_d). - Speedup in mpfr_log1p and mpfr_atanh for small arguments. - Speedup in the mpfr_const_euler function (contributed by Fredrik Johansson), in the computation of Bernoulli numbers (used in mpfr_gamma, mpfr_li2, mpfr_digamma, mpfr_lngamma and mpfr_lgamma), in mpfr_div, in mpfr_fma and mpfr_fms.
73 lines
3.3 KiB
Plaintext
73 lines
3.3 KiB
Plaintext
Copyright 1999, 2001-2018 Free Software Foundation, Inc.
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Contributed by the AriC and Caramba projects, INRIA.
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This file is part of the GNU MPFR Library.
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The GNU MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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The GNU MPFR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
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http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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##############################################################################
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Known bugs:
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* The overflow/underflow exceptions may be badly handled in some functions;
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specially when the intermediary internal results have exponent which
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exceeds the hardware limit (2^30 for a 32 bits CPU, and 2^62 for a 64 bits
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CPU) or the exact result is close to an overflow/underflow threshold.
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* Under Linux/x86 with the traditional FPU, some functions do not work
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if the FPU rounding precision has been changed to single (this is a
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bad practice and should be useless, but one never knows what other
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software will do).
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* Some functions do not use MPFR_SAVE_EXPO_* macros, thus do not behave
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correctly in a reduced exponent range.
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* Function hypot gives incorrect result when on the one hand the difference
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between parameters' exponents is near 2*MPFR_EMAX_MAX and on the other hand
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the output precision or the precision of the parameter with greatest
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absolute value is greater than 2*MPFR_EMAX_MAX-4.
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Potential bugs:
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* Possible incorrect results due to internal underflow, which can lead to
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a huge loss of accuracy while the error analysis doesn't take that into
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account. If the underflow occurs at the last function call (just before
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the MPFR_CAN_ROUND), the result should be correct (or MPFR gets into an
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infinite loop). TODO: check the code and the error analysis.
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* Possible bugs with huge precisions (> 2^30) and a 32-bit ABI, in particular
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undetected integer overflows. TODO: use the MPFR_ADD_PREC macro.
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* Possible bugs if the chosen exponent range does not allow to represent
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the range [1/16, 16].
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* Possible infinite loop in some functions for particular cases: when
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the exact result is an exactly representable number or the middle of
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consecutive two such numbers. However for non-algebraic functions, it is
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believed that no such case exists, except the well-known cases like cos(0)=1,
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exp(0)=1, and so on, and the x^y function when y is an integer or y=1/2^k.
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* The mpfr_set_ld function may be quite slow if the long double type has an
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exponent of more than 15 bits.
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* mpfr_set_d may give wrong results on some non-IEEE architectures.
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* Error analysis for some functions may be incorrect (out-of-date due
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to modifications in the code?).
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* Possible use of non-portable feature (pre-C99) of the integer division
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with negative result.
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