Re: Help with a possible bug
- To: mathgroup at smc.vnet.net
- Subject: [mg99034] Re: Help with a possible bug
- From: Arnoud Buzing <arnoudb at wolfram.com>
- Date: Fri, 24 Apr 2009 03:49:22 -0400 (EDT)
- References: <200904202311.TAA09609@smc.vnet.net>
The issue discussed in this thread has been analyzed and fixed by our development team.
A kernel binary for all affected platforms is currently being tested.
The issue occurs for a somewhat rare class of inputs in Mathematica version 7.0.1 (not 7.0.0).
Users affected by this problem can request a patch by emailing support at wolfram.com.
We apologize for any inconvenience this issue may have caused.
Arnoud Buzing
arnoudb at wolfram.com
Quality Assurance Manager
Wolfram Research
M8R-lj1smh at mailinator.com wrote:
> At work we seem to have stumbled on a strange bug between Table and
> Part. We can reproduce the bug on differently configured Mac and
> Linux boxes. I tried Wolfram support, but they claim they cannot
> reproduce the bug. So I was hoping someone could try it out and
> report their results. Thanks in advance to all volunteers.
>
> For us, the bug is new in 7.0.1. It does not show up in version 6.
> To reproduce it, fill up a 17 x 267 matrix with 3s. Compute the sum
> of some of the columns and you get the result 51 (17 x 3). But if one
> computes the sum for the last few columns, the result is completely
> off. The bug seems to arise from the interaction of optimizations in
> Table and the use of All inside of Part.
>
>
> ------------ code
>
> mat = Table[3, {i, 1, 17}, {j, 1, 267}];
>
> sum = Table[Total[mat[[All, j]]], {j, 1, 249}]
>
> sum1 = Table[Total[mat[[All, j]]], {j, 1, 252}];
> sum2 = Table[Total[mat[[All, j]]], {j, 1, 252}]
>
> ------------ end code
>
> If you look at sum1, it will be correct on a fresh copy of the
> Kernel. The problem only arise from the second time on.
>
> Thanks,
>
> Papin
>
> Email: ImportString["cGFwaW5AY294Lm5ldA==", "Base64"]
>
>
- References:
- Help with a possible bug
- From: M8R-lj1smh@mailinator.com
- Help with a possible bug