Opened 6 years ago

Closed 6 years ago

#12580 closed Bugs (fixed)

cpp_bin_float: Bad rounding in corner case of subtraction

Reported by: Michael Shatz Owned by: John Maddock
Milestone: To Be Determined Component: multiprecision
Version: Boost 1.62.0 Severity: Problem
Keywords: Cc:

Description

Subtraction produces incorrectly rounded result when a small number in range (ULP*0.5..ULP*1.0) subtracted from integer power of 2. The correct answer should be (original number - ULP), but boost returns unmodified original number.

Attachments (1)

sub_from_pow2.cpp​ (940 bytes ) - added by Michael Shatz 6 years ago.
demonstrates incorrect rounding in corner case of subtraction

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Change History (2)

by Michael Shatz, 6 years ago

Attachment: sub_from_pow2.cpp​ added

demonstrates incorrect rounding in corner case of subtraction

comment:1 by John Maddock, 6 years ago

Resolution: → fixed
Status: new → closed

Fixed in ​https://github.com/boostorg/multiprecision/commit/618ef476119f2322d9725d883bf7b93f28a6da26, thanks!

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