patchAxiom Computer Algebra System - Patches: patch #2074, Bug #4733 (rounding of negative...


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patch #2074: Bug #4733 (rounding of negative numbers)

Submitted by:  Bill Page <billpage1>
Submitted on:  Wed 15 Oct 2003 04:07:07 AM UTC  
Category: NonePriority: 5 - Normal
Status: DonePrivacy: Public
Assigned to: Bill Page <billpage1>Open/Closed: Open

Sat 18 Oct 2003 03:35:10 PM UTC, comment #1:

I think this patch could be improved: the definition of shift2 could be modified to not do multiplications (and so presumably be faster).

I also wonder how much the original authors worried about rounding behaviour in some of these calls.

In the function 'normalize', for instance, the old semantics gave 'round towards 0' behaviour; using the new semantics of shift, it would be easy to give 'round towards -infinity' behaviour. But both are wrong: the right method for normalizing floating point numbers, to avoid accumulation of errors, is 'round towards even'.

Dylan Thurston <dpt>
Project Administrator
Wed 15 Oct 2003 04:07:07 AM UTC, original submission:

Just adding Dylan's name, since he did most of the analysis work ...

Bill Page <billpage1>
Project MemberIn charge of this item.


Attached Files
file #6291:  patch_item_2074.patch added by billpage1 (5KiB - text/plain - patch item 2074)


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Follow 3 latest changes.

Date Changed By Updated Field Previous Value => Replaced By
Fri 21 Jan 2005 04:57:41 AM UTCbillpage1StatusNone=>Done
Thu 16 Dec 2004 10:51:11 PM UTCbillpage1Assigned toNone=>billpage1
Wed 15 Oct 2003 04:45:55 AM UTCbillpage1Patch CodeModified - New Version=>

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