Minus zero in Dataset

Hdf-forum archives
1

Hello :slight_smile:

I'm generating some HDF files and in many datasets, when I open with HDFView, some of the values are set to -0.0, but they should be 0.0.

Anyone found this already?

Some hint on what can be?

Best regards,
Eduardo Jauch

路路路

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2

Hi,

0 can be represented as 0.0 and -0.0 in floating point representation. Your
actual data has both, that's all. It doesn't matter.

Cheers,

Matthieu

路路路

2014-02-21 12:22 GMT+00:00 Eduardo Jauch <eduardo.jauch@ist.utl.pt>:

Hello :slight_smile:

I'm generating some HDF files and in many datasets, when I open with
HDFView, some of the values are set to -0.0, but they should be 0.0.

Anyone found this already?

Some hint on what can be?

Best regards,
Eduardo Jauch

--

TECNICO Lisboa - MARETEC
Sec莽茫o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com

聽聽<http://www.ist.utl.pt>
<http://www.mohid.com>

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org

http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

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3

Some floating point representations have both a negative and positive 0.

Possibly you are storing both negative and positive zeros into the file,
and this is what is being reflected in HDFView.

路路路

On Fri, 21 Feb 2014, Eduardo Jauch wrote:

I'm generating some HDF files and in many datasets, when I open with
HDFView, some of the values are set to -0.0, but they should be 0.0.

Anyone found this already?

Some hint on what can be?

--

4

Hola! :slight_smile:

聽聽Could it be -1E-12 which is rounded by10 digits to -0.0 or something like that?

聽聽聽聽Werner

路路路

On 21.02.2014 13:22, Eduardo Jauch wrote:

Hello :slight_smile:

I'm generating some HDF files and in many datasets, when I open with HDFView, some of the values are set to -0.0, but they should be 0.0.

Anyone found this already?

Some hint on what can be?

Best regards,
Eduardo Jauch

--
聽聽TECNICO Lisboa - MARETEC
Sec锟斤拷o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL:www.mohid.com
聽聽聽聽聽聽聽聽聽<www.ist.utl.pt>
<www.mohid.com>

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org
http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

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___________________________________________________________________________
Dr. Werner Benger Visualization Research
Center for Computation & Technology at Louisiana State University (CCT/LSU)
2019 Digital Media Center, Baton Rouge, Louisiana 70803
Tel.: +1 225 578 4809 Fax.: +1 225 578-5362

5

Hi :slight_smile:

I think not. The values are always zero or positive. No negative values are being stored in the file.

Eduardo.

聽聽TECNICO Lisboa - MARETEC
Sec锟斤拷o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com
聽聽聽聽聽聽聽聽聽
<www.ist.utl.pt>
<www.mohid.com>

路路路

Em 21-02-2014 12:34, Werner Benger escreveu:

Hola! :slight_smile:

Could it be -1E-12 which is rounded by10 digits to -0.0 or something like that?

聽聽聽Werner

On 21.02.2014 13:22, Eduardo Jauch wrote:

Hello :slight_smile:

I'm generating some HDF files and in many datasets, when I open with HDFView, some of the values are set to -0.0, but they should be 0.0.

Anyone found this already?

Some hint on what can be?

Best regards,
Eduardo Jauch

--
聽聽TECNICO Lisboa - MARETEC
Sec锟斤拷o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL:www.mohid.com
聽聽聽聽聽聽聽聽聽<www.ist.utl.pt>
<www.mohid.com>

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org
http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

--
___________________________________________________________________________
Dr. Werner Benger Visualization Research
Center for Computation & Technology at Louisiana State University (CCT/LSU)
2019 Digital Media Center, Baton Rouge, Louisiana 70803
Tel.: +1 225 578 4809 Fax.: +1 225 578-5362

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org
http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

6

Hello Matthieu,

The problem is that if I set the values of an array to 0.0, how is it possible that it to be interpreted as -0.0?
And unfortunatelly, it seems it matter. The code that uses this data works if compiled to 64 bits, but fails if compiled to 32 bits...

Cheers,
Eduardo.

聽聽TECNICO Lisboa - MARETEC
Sec锟斤拷o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com
聽聽聽聽聽聽聽聽聽
<www.ist.utl.pt>
<www.mohid.com>

路路路

Em 21-02-2014 12:37, Matthieu Brucher escreveu:

Hi,

0 can be represented as 0.0 and -0.0 in floating point representation. Your actual data has both, that's all. It doesn't matter.

Cheers,

Matthieu

2014-02-21 12:22 GMT+00:00 Eduardo Jauch <eduardo.jauch@ist.utl.pt <mailto:eduardo.jauch@ist.utl.pt>>:

聽聽聽聽Hello :slight_smile:

聽聽聽聽I'm generating some HDF files and in many datasets, when I open
聽聽聽聽with HDFView, some of the values are set to -0.0, but they should
聽聽聽聽be 0.0.

聽聽聽聽Anyone found this already?

聽聽聽聽Some hint on what can be?

聽聽聽聽Best regards,
聽聽聽聽Eduardo Jauch

聽聽聽聽--

聽聽聽聽聽聽聽聽聽聽TECNICO Lisboa - MARETEC
聽聽聽聽Sec锟斤拷o de Ambiente e Energia

聽聽聽聽Av. Rovisco Pais
聽聽聽聽1049-001 Lisboa

聽聽聽聽Tel.:+351 21 8419425 <tel:%2B351%2021%208419425>
聽聽聽聽Fax:+351 21 8417365 <tel:%2B351%2021%208417365>

聽聽聽聽URL:www.mohid.com <http://www.mohid.com>
聽聽聽聽聽聽聽聽聽聽聽聽聽
聽聽聽聽<http://www.ist.utl.pt>
聽聽聽聽<http://www.mohid.com>

聽聽聽聽_______________________________________________
聽聽聽聽Hdf-forum is for HDF software users discussion.
聽聽聽聽Hdf-forum@lists.hdfgroup.org <mailto:Hdf-forum@lists.hdfgroup.org>
聽聽聽聽http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

--
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Blog: http://matt.eifelle.com
LinkedIn: http://www.linkedin.com/in/matthieubrucher
Music band: http://liliejay.com/

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org
http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

7

Hum...

I'm pretty sure that I'm not storing any "negative" zero in the file.
At least, it shouldn't, once the values are being provided by the user (me) and I'm providing only positive zeros (0.0).

I'll investigate more to see if there is something wrong in the code.

Thanks,
Eduardo

聽聽TECNICO Lisboa - MARETEC
Sec锟斤拷o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com
聽聽聽聽聽聽聽聽聽
<www.ist.utl.pt>
<www.mohid.com>

路路路

Em 21-02-2014 12:41, Ben Clifford escreveu:

On Fri, 21 Feb 2014, Eduardo Jauch wrote:

I'm generating some HDF files and in many datasets, when I open with
HDFView, some of the values are set to -0.0, but they should be 0.0.

Anyone found this already?

Some hint on what can be?

Some floating point representations have both a negative and positive 0.

Possibly you are storing both negative and positive zeros into the file,
and this is what is being reflected in HDFView.

8

If your code fails with those values, then something is definitely wrong in
your code. 0.0 and -0.0 behaves the same in floating point computations.
You can check the binary representation of the data, just to check that it
really is 0, and not some other small negative value.

Cheers,

Matthieu

路路路

2014-02-21 13:16 GMT+00:00 Eduardo Jauch <eduardo.jauch@ist.utl.pt>:

Hello Matthieu,

The problem is that if I set the values of an array to 0.0, how is it
possible that it to be interpreted as -0.0?
And unfortunatelly, it seems it matter. The code that uses this data works
if compiled to 64 bits, but fails if compiled to 32 bits...

Cheers,
Eduardo.

TECNICO Lisboa - MARETEC
Sec莽茫o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com

聽聽<http://www.ist.utl.pt>
<http://www.mohid.com>
Em 21-02-2014 12:37, Matthieu Brucher escreveu:

Hi,

0 can be represented as 0.0 and -0.0 in floating point representation.
Your actual data has both, that's all. It doesn't matter.

Cheers,

Matthieu

2014-02-21 12:22 GMT+00:00 Eduardo Jauch <eduardo.jauch@ist.utl.pt>:

Hello :slight_smile:

I'm generating some HDF files and in many datasets, when I open with
HDFView, some of the values are set to -0.0, but they should be 0.0.

Anyone found this already?

Some hint on what can be?

Best regards,
Eduardo Jauch

--

TECNICO Lisboa - MARETEC
Sec莽茫o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com

聽聽<http://www.ist.utl.pt>
<http://www.mohid.com>

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org

http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

--
Information System Engineer, Ph.D.
Blog: http://matt.eifelle.com
LinkedIn: http://www.linkedin.com/in/matthieubrucher
Music band: http://liliejay.com/

_______________________________________________
Hdf-forum is for HDF software users discussion.Hdf-forum@lists.hdfgroup.orghttp://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org

http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

--
Information System Engineer, Ph.D.
Blog: http://matt.eifelle.com
LinkedIn: http://www.linkedin.com/in/matthieubrucher
Music band: http://liliejay.com/

9

Hello Matthieu,

I think you're right.

After inspecting the code, it fails not because of the -0.0, but because of a problem associated with an "access violation", and HDF's with only "positive" zeroes also causes the program to crash-

Strangely the error happens only when I read HDF's in 32 bit compiled programs.
But there is a lot o things that can be causing this.

But most probably is something associated with compilation options or exxternal libraries used. The code used to work in 32 bits and recently we changed the compiler.

I'll update it (the compiler) and see if it fix this issue with the 32 bit version.

Thanks!
Eduardo

聽聽TECNICO Lisboa - MARETEC
Sec锟斤拷o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com
聽聽聽聽聽聽聽聽聽
<www.ist.utl.pt>
<www.mohid.com>

路路路

Em 21-02-2014 13:24, Matthieu Brucher escreveu:

If your code fails with those values, then something is definitely wrong in your code. 0.0 and -0.0 behaves the same in floating point computations.
You can check the binary representation of the data, just to check that it really is 0, and not some other small negative value.

Cheers,

Matthieu

2014-02-21 13:16 GMT+00:00 Eduardo Jauch <eduardo.jauch@ist.utl.pt <mailto:eduardo.jauch@ist.utl.pt>>:

聽聽聽聽Hello Matthieu,

聽聽聽聽The problem is that if I set the values of an array to 0.0, how is
聽聽聽聽it possible that it to be interpreted as -0.0?
聽聽聽聽And unfortunatelly, it seems it matter. The code that uses this
聽聽聽聽data works if compiled to 64 bits, but fails if compiled to 32 bits...

聽聽聽聽Cheers,
聽聽聽聽Eduardo.

聽聽聽聽聽聽聽聽聽聽TECNICO Lisboa - MARETEC
聽聽聽聽Sec锟斤拷o de Ambiente e Energia

聽聽聽聽Av. Rovisco Pais
聽聽聽聽1049-001 Lisboa

聽聽聽聽Tel.:+351 21 8419425 <tel:%2B351%2021%208419425>
聽聽聽聽Fax:+351 21 8417365 <tel:%2B351%2021%208417365>

聽聽聽聽URL:www.mohid.com <http://www.mohid.com>
聽聽聽聽聽聽聽聽聽聽聽聽聽
聽聽聽聽<http://www.ist.utl.pt>
聽聽聽聽<http://www.mohid.com>
聽聽聽聽Em 21-02-2014 12 <tel:21-02-2014%2012>:37, Matthieu Brucher escreveu:

聽聽聽聽Hi,

聽聽聽聽0 can be represented as 0.0 and -0.0 in floating point
聽聽聽聽representation. Your actual data has both, that's all. It doesn't
聽聽聽聽matter.

聽聽聽聽Cheers,

聽聽聽聽Matthieu

聽聽聽聽2014-02-21 12:22 GMT+00:00 Eduardo Jauch
聽聽聽聽<eduardo.jauch@ist.utl.pt <mailto:eduardo.jauch@ist.utl.pt>>:

聽聽聽聽聽聽聽聽Hello :slight_smile:

聽聽聽聽聽聽聽聽I'm generating some HDF files and in many datasets, when I
聽聽聽聽聽聽聽聽open with HDFView, some of the values are set to -0.0, but
聽聽聽聽聽聽聽聽they should be 0.0.

聽聽聽聽聽聽聽聽Anyone found this already?

聽聽聽聽聽聽聽聽Some hint on what can be?

聽聽聽聽聽聽聽聽Best regards,
聽聽聽聽聽聽聽聽Eduardo Jauch

聽聽聽聽聽聽聽聽--

聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽TECNICO Lisboa - MARETEC
聽聽聽聽聽聽聽聽Sec锟斤拷o de Ambiente e Energia

聽聽聽聽聽聽聽聽Av. Rovisco Pais
聽聽聽聽聽聽聽聽1049-001 Lisboa

聽聽聽聽聽聽聽聽Tel.:+351 21 8419425 <tel:%2B351%2021%208419425>
聽聽聽聽聽聽聽聽Fax:+351 21 8417365 <tel:%2B351%2021%208417365>

聽聽聽聽聽聽聽聽URL:www.mohid.com <http://www.mohid.com>
聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽
聽聽聽聽聽聽聽聽<http://www.ist.utl.pt>
聽聽聽聽聽聽聽聽<http://www.mohid.com>

聽聽聽聽聽聽聽聽_______________________________________________
聽聽聽聽聽聽聽聽Hdf-forum is for HDF software users discussion.
聽聽聽聽聽聽聽聽Hdf-forum@lists.hdfgroup.org
聽聽聽聽聽聽聽聽<mailto:Hdf-forum@lists.hdfgroup.org>
聽聽聽聽聽聽聽聽http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

聽聽聽聽-- Information System Engineer, Ph.D.
聽聽聽聽Blog: http://matt.eifelle.com
聽聽聽聽LinkedIn: http://www.linkedin.com/in/matthieubrucher
聽聽聽聽Music band: http://liliejay.com/

聽聽聽聽_______________________________________________
聽聽聽聽Hdf-forum is for HDF software users discussion.
聽聽聽聽Hdf-forum@lists.hdfgroup.org <mailto:Hdf-forum@lists.hdfgroup.org>
聽聽聽聽http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

聽聽聽聽_______________________________________________
聽聽聽聽Hdf-forum is for HDF software users discussion.
聽聽聽聽Hdf-forum@lists.hdfgroup.org <mailto:Hdf-forum@lists.hdfgroup.org>
聽聽聽聽http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

--
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Blog: http://matt.eifelle.com
LinkedIn: http://www.linkedin.com/in/matthieubrucher
Music band: http://liliejay.com/

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org
http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

10

Just want to point out that 0.0 or -0.0 can give vastly different floating
point results, such as in 1/x. But it's probably not relevant for this case.

路路路

On Fri, Feb 21, 2014 at 2:47 PM, Eduardo Jauch <eduardo.jauch@ist.utl.pt>wrote:

Hello Matthieu,

I think you're right.

After inspecting the code, it fails not because of the -0.0, but because
of a problem associated with an "access violation", and HDF's with only
"positive" zeroes also causes the program to crash-

Strangely the error happens only when I read HDF's in 32 bit compiled
programs.
But there is a lot o things that can be causing this.

But most probably is something associated with compilation options or
exxternal libraries used. The code used to work in 32 bits and recently we
changed the compiler.

I'll update it (the compiler) and see if it fix this issue with the 32 bit
version.

Thanks!
Eduardo

TECNICO Lisboa - MARETEC
Sec莽茫o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com

聽聽<http://www.ist.utl.pt>
<http://www.mohid.com>
Em 21-02-2014 13:24, Matthieu Brucher escreveu:

If your code fails with those values, then something is definitely wrong
in your code. 0.0 and -0.0 behaves the same in floating point computations.
You can check the binary representation of the data, just to check that it
really is 0, and not some other small negative value.

Cheers,

Matthieu

2014-02-21 13:16 GMT+00:00 Eduardo Jauch <eduardo.jauch@ist.utl.pt>:

Hello Matthieu,

The problem is that if I set the values of an array to 0.0, how is it
possible that it to be interpreted as -0.0?
And unfortunatelly, it seems it matter. The code that uses this data
works if compiled to 64 bits, but fails if compiled to 32 bits...

Cheers,
Eduardo.

TECNICO Lisboa - MARETEC
Sec莽茫o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com

聽聽<http://www.ist.utl.pt>
<http://www.mohid.com>
Em 21-02-2014 12:37, Matthieu Brucher escreveu:

Hi,

0 can be represented as 0.0 and -0.0 in floating point representation.
Your actual data has both, that's all. It doesn't matter.

Cheers,

Matthieu

2014-02-21 12:22 GMT+00:00 Eduardo Jauch <eduardo.jauch@ist.utl.pt>:

Hello :slight_smile:

I'm generating some HDF files and in many datasets, when I open with
HDFView, some of the values are set to -0.0, but they should be 0.0.

Anyone found this already?

Some hint on what can be?

Best regards,
Eduardo Jauch

--

TECNICO Lisboa - MARETEC
Sec莽茫o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com

聽聽<http://www.ist.utl.pt>
<http://www.mohid.com>

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org

http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

--
Information System Engineer, Ph.D.
Blog: http://matt.eifelle.com
LinkedIn: http://www.linkedin.com/in/matthieubrucher
Music band: http://liliejay.com/

_______________________________________________
Hdf-forum is for HDF software users discussion.Hdf-forum@lists.hdfgroup.orghttp://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org

http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

--
Information System Engineer, Ph.D.
Blog: http://matt.eifelle.com
LinkedIn: http://www.linkedin.com/in/matthieubrucher
Music band: http://liliejay.com/

_______________________________________________
Hdf-forum is for HDF software users discussion.Hdf-forum@lists.hdfgroup.orghttp://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org

http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org

11

Hum...

Interesting.
Mybe this will also afect "if's" that relay on defining if a value is >= 0.0, for example?

Anyway, I'll investigate also why the software that generates the HDF is (sometimes )creating -0.0 instead of 0.0.

Cheers,
Eduardo.

聽聽TECNICO Lisboa - MARETEC
Sec锟斤拷o de Ambiente e Energia

Av. Rovisco Pais
1049-001 Lisboa

Tel.: +351 21 8419425
Fax: +351 21 8417365

URL: www.mohid.com
聽聽聽聽聽聽聽聽聽
<www.ist.utl.pt>
<www.mohid.com>

路路路

Em 21-02-2014 13:55, Filipe Maia escreveu:

Just want to point out that 0.0 or -0.0 can give vastly different floating point results, such as in 1/x. But it's probably not relevant for this case.

On Fri, Feb 21, 2014 at 2:47 PM, Eduardo Jauch > <eduardo.jauch@ist.utl.pt <mailto:eduardo.jauch@ist.utl.pt>> wrote:

聽聽聽聽Hello Matthieu,

聽聽聽聽I think you're right.

聽聽聽聽After inspecting the code, it fails not because of the -0.0, but
聽聽聽聽because of a problem associated with an "access violation", and
聽聽聽聽HDF's with only "positive" zeroes also causes the program to crash-

聽聽聽聽Strangely the error happens only when I read HDF's in 32 bit
聽聽聽聽compiled programs.
聽聽聽聽But there is a lot o things that can be causing this.

聽聽聽聽But most probably is something associated with compilation options
聽聽聽聽or exxternal libraries used. The code used to work in 32 bits and
聽聽聽聽recently we changed the compiler.

聽聽聽聽I'll update it (the compiler) and see if it fix this issue with
聽聽聽聽the 32 bit version.

聽聽聽聽Thanks!
聽聽聽聽Eduardo

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聽聽聽聽Em 21-02-2014 13 <tel:21-02-2014%2013>:24, Matthieu Brucher escreveu:

聽聽聽聽If your code fails with those values, then something is
聽聽聽聽definitely wrong in your code. 0.0 and -0.0 behaves the same in
聽聽聽聽floating point computations.
聽聽聽聽You can check the binary representation of the data, just to
聽聽聽聽check that it really is 0, and not some other small negative value.

聽聽聽聽Cheers,

聽聽聽聽Matthieu

聽聽聽聽2014-02-21 13:16 GMT+00:00 Eduardo Jauch
聽聽聽聽<eduardo.jauch@ist.utl.pt <mailto:eduardo.jauch@ist.utl.pt>>:

聽聽聽聽聽聽聽聽Hello Matthieu,

聽聽聽聽聽聽聽聽The problem is that if I set the values of an array to 0.0,
聽聽聽聽聽聽聽聽how is it possible that it to be interpreted as -0.0?
聽聽聽聽聽聽聽聽And unfortunatelly, it seems it matter. The code that uses
聽聽聽聽聽聽聽聽this data works if compiled to 64 bits, but fails if compiled
聽聽聽聽聽聽聽聽to 32 bits...

聽聽聽聽聽聽聽聽Cheers,
聽聽聽聽聽聽聽聽Eduardo.

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聽聽聽聽聽聽聽聽Em 21-02-2014 12 <tel:21-02-2014%2012>:37, Matthieu Brucher >> escreveu:

聽聽聽聽聽聽聽聽Hi,

聽聽聽聽聽聽聽聽0 can be represented as 0.0 and -0.0 in floating point
聽聽聽聽聽聽聽聽representation. Your actual data has both, that's all. It
聽聽聽聽聽聽聽聽doesn't matter.

聽聽聽聽聽聽聽聽Cheers,

聽聽聽聽聽聽聽聽Matthieu

聽聽聽聽聽聽聽聽2014-02-21 12:22 GMT+00:00 Eduardo Jauch
聽聽聽聽聽聽聽聽<eduardo.jauch@ist.utl.pt <mailto:eduardo.jauch@ist.utl.pt>>:

聽聽聽聽聽聽聽聽聽聽聽聽Hello :slight_smile:

聽聽聽聽聽聽聽聽聽聽聽聽I'm generating some HDF files and in many datasets, when
聽聽聽聽聽聽聽聽聽聽聽聽I open with HDFView, some of the values are set to -0.0,
聽聽聽聽聽聽聽聽聽聽聽聽but they should be 0.0.

聽聽聽聽聽聽聽聽聽聽聽聽Anyone found this already?

聽聽聽聽聽聽聽聽聽聽聽聽Some hint on what can be?

聽聽聽聽聽聽聽聽聽聽聽聽Best regards,
聽聽聽聽聽聽聽聽聽聽聽聽Eduardo Jauch

聽聽聽聽聽聽聽聽聽聽聽聽--

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