[SciPy-Dev] Updating constants

Vincent Davis vincent@vincentdavis....
Fri Jun 11 13:46:02 CDT 2010


On Thu, Jun 10, 2010 at 11:29 PM,  <josef.pktd@gmail.com> wrote:
> On Fri, Jun 11, 2010 at 1:09 AM, Vincent Davis <vincent@vincentdavis.net> wrote:
>> On Thu, Jun 10, 2010 at 10:54 PM, Vincent Davis
>> <vincent@vincentdavis.net> wrote:
>>> On Thu, Jun 10, 2010 at 10:38 PM,  <josef.pktd@gmail.com> wrote:
>>>> On Fri, Jun 11, 2010 at 12:11 AM, Vincent Davis
>>>> <vincent@vincentdavis.net> wrote:
>>>>> The current constants in scipy are from 2002, the newest set available
>>>>> are from 2006.
>>>>> Should they be updated, What are the issues with updating with regard
>>>>> to notifying users ie documenting the update.
>>>>
>>>> I thought these are constants. Did they change the value of Pi recently?
>>>
>>> They found more digits of Pi :)
>>> I was referring to "Fundamental Physical Constants" scipy.constants.codata
>>> I don't know, it's not easy to compare. I assume there was a reason
>>> they updated the list. There is an Uncertainty value on many of them
>>> so I assume the actual value don't change but our estimate does.
>>>
>>> http://physics.nist.gov/cuu/Constants/index.html
>>> release dates 1986, 1998, 2002, 2006
>>>
>>> Vincent
>>>
>>>>
>>>> just curious: What has changed?
>>>>
>>
>> I just relived I can update the constants and then compare them with
>> the old. Should be quick, I will send out the diff in the morning.
>
> quote from the REVIEWS OF MODERN PHYSICS paper:
>
> "Although just four years separate the 31 December closing dates of
> the 2002 and 2006 adjustments, there are a number of important new
> results to consider. Experimental advances include the 2003 Atomic
> Mass Evaluation from the Atomic Mass Data Center (AMDC),which provides
> new values for the relative atomic masses Ar(X) of a number of
> relevant atoms; a new value of ..."

Ok a few more issues/question about constants.codata.
Some of the names seem rather messed up because of how the raw text is
 read. For example
Loschmidt constant (273.15 K, 101.325 kPa)             2.686 7774 e25
      0.000 0047 e25        m^-3

The above line gets added to the physical_constants dict with the key
value 'Loschmidt constant (273.15 K, 101.325 kPa)'.
codata.value('Loschmidt constant (273.15 K, 101.325 kPa)')
2.6867773000000001e+25

Seems like it should be no more that 'Loschmidt constant' and I would
recommend 'Loschmidt' unless there is a conflict.

So as well as updating the variable constants :) I would like to
update naming issue like this above.
Should I? , What kind of warning should there be......?

Vincent
>
> Josef
> “Curiouser and curiouser!”
>
>>
>> Vincent
>>
>>
>>>> Josef
>>>>
>>>>>
>>>>> Vincent
>>>>> _______________________________________________
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>>>>>
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>>>
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