[issue40855] statistics.stdev ignore xbar argument

2020-06-17 Thread Matti


Matti  added the comment:

I meant to write "pre-calculate".

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[issue40855] statistics.stdev ignore xbar argument

2020-06-17 Thread Matti


Matti  added the comment:

>I see what you're trying to do but think that interpretation is surprising
>and is at odds with the existing and intended uses of the *xbar* argument.  
>
>The goals were to allow the mean to be precomputed (common case) or to be 
>recentered (uncommon).  Neither case should have the effect of changing the 
>divisor.  
>
>We can't break existing code that assumes that stdev(data) is equal to 
>stdev(data, xbar=mean(data)).

Maybe the requirement are buged? It seems to me that recalculating the mean is 
a very niche use case. You will very little time on a call you do once. 

But what good is it to supply a re-centered mean if you get a wrong estimation 
of the standard deviation? If the mean is not the mean of the sample it was not 
calculated using the sample so there is no loos of degrees of freedom.

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[issue40855] statistics.stdev ignore xbar argument

2020-06-11 Thread Matti


Matti  added the comment:

Hi Raymond and Steven!

I'm happy that you are solving this issue but do you have any comment on my 
previous answer?

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[issue40855] statistics.stdev ignore xbar argument

2020-06-04 Thread Matti

Matti  added the comment:

If we estimate the mean using a sample we loose one degree of freedom so it 
will be divided by N-1, while if we have the mean independent of the sample it 
should be divided by N to be unbiased. 

i.e. 
example 1 
sqrt(((1-1.5)²+(2-1.5)²)/(2-1)) = 0.7...
example 3
sqrt(((1-1.5)²+(2-1.5)²)/(2)) = 0.5

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[issue40855] statistics.stdev ignore xbar argument

2020-06-03 Thread Matti


New submission from Matti :

statistics.variance also has the same problem. 

>>> import statistics
>>> statistics.stdev([1,2])
0.7071067811865476
>>> statistics.stdev([1,2], 3)
0.7071067811865476
>>> statistics.stdev([1,2], 1.5)
0.7071067811865476

should be 
0.7071067811865476
2.23606797749979
0.5

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messages: 370659
nosy: Folket
priority: normal
severity: normal
status: open
title: statistics.stdev ignore xbar argument
type: behavior
versions: Python 3.6

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[issue14897] struct.pack raises unexpected error message

2012-10-30 Thread Matti Mäki

Matti Mäki added the comment:

I filled up the contributor form and gave it to Petri Lehtinen 2012-10-22

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[issue14897] struct.pack raises unexpected error message

2012-10-23 Thread Matti Mäki

Matti Mäki added the comment:

A second try, now taking into account buffer and offset params in pack_into.

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Added file: http://bugs.python.org/file27689/issue14897-2.patch

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[issue14897] struct.pack raises unexpected error message

2012-10-23 Thread Matti Mäki

Matti Mäki added the comment:

Changed the error message as suggested by 
http://bugs.python.org/issue14897#msg161493

Also made similar change to struct.pack_into

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keywords: +patch
nosy: +makimat
Added file: http://bugs.python.org/file27679/issue14897.patch

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[issue1912] Segmentation fault

2008-01-22 Thread Matti Punkeri

Matti Punkeri added the comment:

And the program is running on SuSE Linux, 2.6.11.4-20a-default, gcc 
version 3.3.5

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[issue1912] Segmentation fault

2008-01-22 Thread Matti Punkeri

New submission from Matti Punkeri:

Python seg faults after 20-30 hours. The running Python application is 
a Qt based user interface which handles several SSH threads. Backtrace 
is attached.

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files: backtrace.txt
messages: 61558
nosy: mpunkeri
severity: major
status: open
title: Segmentation fault
type: crash
versions: Python 2.4
Added file: http://bugs.python.org/file9270/backtrace.txt

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[issue1239] openpty does not give bidirectional pipe

2007-10-05 Thread Matti Katila

Matti Katila added the comment:

Not a real issue - it's a standard behaviour of tty.

Fix is to set -icanon:

m,s = os.openpty()
s = os.ttyname(s)
os.system( 'stty cs8 -icanon -echo < %s' % s )

see, http://www.eulogika.net/download/eutalk_20040302/pymouse.html

The issue can be closed and documentation can be updated with some
helpful information.

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[issue1239] openpty does not give bidirectional pipe

2007-10-05 Thread Matti Katila

Matti Katila added the comment:

Linux Programmer’s Manual for ptmx and pts - pseudo-terminal master and
slave states:

"Data written to the slave is presented  on  the  master descriptor  as
input. Data written to the master is presented to the slave as input."

The data can be read from slave to master but not from master to slave.

The unit test does not test this issue either:
http://coverage.livinglogic.de/Lib/test/test_openpty.py.html

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[issue1239] openpty does not give bidirectional pipe

2007-10-05 Thread Matti Katila

New submission from Matti Katila:

http://rafb.net/p/t8cqSt71.html

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nosy: +mudyc

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[issue1239] openpty does not give bidirectional pipe

2007-10-05 Thread Matti Katila

Changes by Matti Katila:


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components: None
severity: normal
status: open
title: openpty does not give bidirectional pipe
type: behavior
versions: Python 2.5

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