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[#6216] Potential bugs -- To analyse

Date:
2008-09-16 13:39
Priority:
1
State:
Open
Submitted by:
Patrick PELISSIER (pphd)
Assigned to:
Nobody (None)
Category:
general
Resolution:
None
Target Version:
Future
 
Summary:
Potential bugs -- To analyse

Detailed description
* Possible incorrect results due to internal underflow, which can lead to
a huge loss of accuracy while the error analysis doesn't take that into
account. If the underflow occurs at the last function call (just before
the MPFR_CAN_ROUND), the result should be correct (or MPFR gets into an
infinite loop). TODO: check the code and the error analysis.

* Possible integer overflows on some machines.

* Possible bugs with huge precisions (> 2^30).

* Possible bugs if the chosen exponent range does not allow to represent
the range [1/16, 16].

* Possible infinite loop in some functions for particular cases: when
the exact result is an exactly representable number or the middle of
consecutive two such numbers. However for non-algebraic functions, it is
believed that no such case exists, except the well-known cases like cos(0)=1,
exp(0)=1, and so on, and the x^y function when y is an integer or y=1/2^k.

* The mpfr_set_ld function may be quite slow if the long double type has an
exponent of more than 15 bits.

* mpfr_set_d may give wrong results on some non-IEEE architectures.

* Error analysis for some functions may be incorrect (out-of-date due
to modifications in the code?).

* Possible use of non-portable feature (pre-C99) of the integer division
with negative result.

Followup

No Followups Have Been Posted

Attached Files:

Changes:

Field Old Value Date By
summaryPotential bugs -- To analyse [need review]2008-09-17 09:23zimmerma
summaryPotential bugs -- To analyse2008-09-17 09:23zimmerma