-- Wolfram Research QA process defect: Bug in Mathematica 6 - Integrate - 92 (Log, Sqrt, invalid value, regression bug) - BUG THE LONG LIVER: 1996-2008 (!)

[Vladimir Bondarenko]

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If the same bugs exists through numerous software releases,
I think that is valuable public information.

It just should not happen.

-- Brad Cooper

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-- NOT FIXED BUGS ARE DANGEROUS: THEY TEND TO GET MORE SEVERE --
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Quality of CASs is our #1 care.

So our little demo continues.... Hello again from the VM machine
which hopefully soon will be used by CAS manufacturers to the
benefit of their customers.

This example demonstrates YET ANOTHER case of bad defects in the
Wolfram Research Quality Assurance process. Consider, it cannot
trap and fix efficiently bugs the long livers.

The reported here defect persists in the Mathematica versions
since at least 1996 to 2008.

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N[ 2 - Pi/2 - Pi Log[2]/2 ]
NIntegrate[Log[z] Log[1 + Sqrt[1 - z^2]], {z, 0, 1}]

-0.659589
-0.659589

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N[Integrate[Log[z] Log[1 + Sqrt[1 - z^2]], {z, 0, 1}]]

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VERSION OUTPUT RESOLUTION
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Mathematica 6.0 -0.707202 <--------------------------- BUG #3

Mathematica 5.2 Unevaluated <------------------------- BUG #2

Mathematica 4.2 0 <----------------------------------- BUG #1

Mathematica 3.0 -0.659589 OK

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Best wishes,

Vladimir Bondarenko

VM and GEMM architect
Co-founder, CEO, Mathematical Director

http://www.cybertester.com/ Cyber Tester, LLC
http://maple.bug-list.org/ Maple Bugs Encyclopaedia
http://www.CAS-testing.org/ CAS Testing

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"We must understand that technologies
like these are the way of the future."

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[David W. Cantrell]

Vladimir Bondarenko <v...@cybertester.com> wrote:
>
> N[ 2 - Pi/2 - Pi Log[2]/2 ]
> NIntegrate[Log[z] Log[1 + Sqrt[1 - z^2]], {z, 0, 1}]
>
> -0.659589
> -0.659589
>
> -----------------------------------------------------------------
>
> N[Integrate[Log[z] Log[1 + Sqrt[1 - z^2]], {z, 0, 1}]]
>
> -----------------------------------------------------------------
> VERSION OUTPUT RESOLUTION
> -----------------------------------------------------------------
>
> Mathematica 6.0 -0.707202 <--------------------------- BUG #3
>
> Mathematica 5.2 Unevaluated <------------------------- BUG #2
>
> Mathematica 4.2 0 <----------------------------------- BUG #1
>
> Mathematica 3.0 -0.659589 OK

I am happy to report that this bug has already been fixed in version 6.0.2:

In[9]:= N[Integrate[Log[z] Log[1 + Sqrt[1 - z^2]], {z, 0, 1}]]

Out[9]= -0.659589

But I am unhappy to report that most of the bugs which Vladimir mentioned
in version 6 or 6.0.1 are still present in 6.0.2.

David

[Bhuvanesh]

On Feb 28, 11:28 am, David W. Cantrell <DWCantr...@sigmaxi.net> wrote:
> I am happy to report that this bug has already been fixed in version 6.0.2:
>
> In[9]:= N[Integrate[Log[z] Log[1 + Sqrt[1 - z^2]], {z, 0, 1}]]
>
> Out[9]= -0.659589
>
> But I am unhappy to report that most of the bugs which Vladimir mentioned
> in version 6 or 6.0.1 are still present in 6.0.2.
>
> David

Right, most of those were fixed in the development version (i.e. what
will be the next major version), not in 6.0.2.

Also, this particular example returns unevaluated (the antiderivative
given by version 3 was not correct in general).

Bhuvanesh