Entropy calculation incorrect?

Community matplotlib-users
1

Hello,

I have been using the matplotlib.mlab.entropy function and have noticed that it may be incorrect. I have posted a question on stackoverflow here:

http://stackoverflow.com/questions/23291576/matplotlib-mlab-entropy-calculation-incorrect

I thought I would should it on the mailing list too. Does anyone have any ideas?

Thanks,

Nathan

2

Nathan,

Thanks for bringing this up. It looks like the short-term fix is to make the documentation match the code. Longer term, it seems to me like this is the sort of thing that should be deprecated; it doesn't belong in matplotlib any more.

Would you open an issue on Github, please? Even better: submit a pull request that fixes the documentation.

Eric

···

On 2014/04/25 1:26 AM, Nathan Lindop wrote:

Hello,

I have been using the matplotlib.mlab.entropy function and have noticed
that it may be incorrect. I have posted a question on stackoverflow here:
python - Matplotlib mlab entropy calculation incorrect? - Stack Overflow

I thought I would should it on the mailing list too. Does anyone have
any ideas?

Thanks,
Nathan

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3

Eric,

Thanks. I have submitted a pull request to fix the documentation as you suggested.

Thanks for your help,

Nathan (aka captainwhippet)

···

From: Eric Firing <efiring@…202…>
To: matplotlib-users@lists.sourceforge.net
Sent: Friday, 25 April 2014, 19:38
Subject: Re: [Matplotlib-users] Entropy calculation incorrect?

Nathan,

Thanks for bringing this up. It looks like the short-term fix is to
make the documentation match the code. Longer term, it seems to me like
this is the sort of thing that should be deprecated; it doesn’t belong
in matplotlib any more.

Would you open an issue on Github, please? Even better: submit a
pull
request that fixes the documentation.

Eric

On 2014/04/25 1:26 AM, Nathan Lindop wrote:

Hello,

I have been using the matplotlib.mlab.entropy function and have noticed
that it may be incorrect. I have posted a question on stackoverflow here:
http://stackoverflow.com/questions/23291576/matplotlib-mlab-entropy-calculation-incorrect

I thought I would should it on the mailing list too. Does anyone have
any ideas?

Thanks,
Nathan

Start Your Social Network Today - Download eXo Platform
Build your Enterprise Intranet with eXo Platform Software
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Ready
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4

This is a side-remark.

Please, don't exaggerate with the term "incorrect". Binary, decimal, natural... logarithms, all this is just a matter of multiplicative CONSTANT, and sometimes a question of convention.
I am a physicist, and for "us" the entropy is NOT given in bits. We use natural logarithms, and in order to have the units appropriate for statistical physics / thermodynamics, we multiply the result by the Boltzmann constant, 1.38*10^(-23) Joule/Kelvin, and that's it.

Anyway, Eric Firing is right, all this has nothing to do with Matplotlib.

Best regards.
Jerzy Karczmarczuk

5

Jerzy,

Yes, understood.

The issue here is that the function is documented incorrectly and I have made a pull request to fix that.

Best regards,

Nathan.

···

From: Jerzy Karczmarczuk <jerzy.karczmarczuk@…3937…>
To: matplotlib-users@…712…orge.net
Sent: Monday, 28 April 2014, 10:02
Subject: Re: [Matplotlib-users] Entropy calculation incorrect?

This is a side-remark.

Please, don’t exaggerate with the term “incorrect”. Binary, decimal,
natural… logarithms, all this is just a matter of multiplicative
CONSTANT, and sometimes a question of convention.
I am a physicist, and for “us” the entropy is NOT given in bits. We use
natural logarithms, and in order to have the units appropriate for
statistical physics / thermodynamics, we multiply the result by the
Boltzmann constant, 1.38*10^(-23) Joule/Kelvin, and that’s it.

Anyway, Eric Firing is right, all this has nothing to do with Matplotlib.

Best regards.
Jerzy
Karczmarczuk

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