Jussi Salmela <[EMAIL PROTECTED]> wrote:
> I've run a couple of tests and it seems to me that Dennis Lee Bieber
is
> on the trail of the truth when he claims that smallest magnitude to
> the largest is the way to do the summation. Actually it isn't THE way
> although it diminishes the error.
Duncan Booth kirjoitti:
> Dennis Lee Bieber <[EMAIL PROTECTED]> wrote:
>
>> For floating point, smallest magnitude to largest IS the most
>> precise.
>>
>> Pretend you only have 2 significant digits of precision...
>>
>> 10 + 0.4 + 0.4 + 0.4 => 10
>>
>> 0.4 + 0.4 + 0.4 + 10 =>
Dennis Lee Bieber <[EMAIL PROTECTED]> wrote:
> For floating point, smallest magnitude to largest IS the most
> precise.
>
> Pretend you only have 2 significant digits of precision...
>
> 10 + 0.4 + 0.4 + 0.4 => 10
>
> 0.4 + 0.4 + 0.4 + 10 => 11
and if you try the way I sugg
Steven D'Aprano <[EMAIL PROTECTED]> wrote:
> If the values vary greatly in magnitude, you probably want to add them
> from smallest to biggest; other than that, how else can you calculate the
> mean?
>
It doesn't have to be smallest to largest, but the important thing is not
to be adding the mil
On 2007-02-27, Steven D'Aprano <[EMAIL PROTECTED]> wrote:
> On Tue, 27 Feb 2007 10:06:29 +, Duncan Booth wrote:
>> Adding up a long list of values and then dividing by the
>> number of values is the classic computer science example of
>> how to get an inaccurate answer from a floating point
>>
On Tue, 27 Feb 2007 10:06:29 +, Duncan Booth wrote:
> Adding up a long list of values
> and then dividing by the number of values is the classic computer
> science example of how to get an inaccurate answer from a floating point
> calculation.
I'm not entirely ignorant when it comes to com
Dennis Lee Bieber <[EMAIL PROTECTED]> wrote:
> Something like (pseudo-code):
>
>
> cnt = 0
> for rw in cursor():
> if cnt:
> for i,v in enumerate(rw):
>sum[i] += v #accumulate next row
> else:
> sum = rw #initialize to first row
>
Leif K-Brooks wrote:
> [EMAIL PROTECTED] wrote:
>> ...
>> Unfortunately, when I try to use that last list in a NumPy function,
>> I'm told that it cannot be broadcast to the correct shape. So, what I
>> want to do is strip the extra brackes from each end to leave just
>> [3.5, 4.5, 5.5, 6.5, 7.5].
On 2007-02-27, Leif K-Brooks <[EMAIL PROTECTED]> wrote:
Lief, Bjoern:
> l = l[0]
Of course! If I had let it work in my mind overnight I would almost
certainly have seen this.
Thank you both for your patient responses,
Rich
--
http://mail.python.org/mailman/listinfo/python-list
[EMAIL PROTECTED] wrote:
> I end up with a single list, but with two brackets on each end,
> for example, [[3.5, 4.5, 5.5, 6.5, 7.5]].
>
> Unfortunately, when I try to use that last list in a NumPy
> function, I'm
> told that it cannot be broadcast to the correct shape. So, what I
> want to d
[EMAIL PROTECTED] wrote:
> So I have lists that look like this: [1, 2, 3, 4, 5]. When I
> concatenate lists, I end up with a list of lists that looks like
> this: [[1, 2, 3. 4, 5]. [6, 7. 8, 9. 10]].
Really?
>>> [1, 2, 3, 4, 5] + [6, 7, 8, 9, 10]
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
> Then, I aver
I start with a list of tuples retrieved from a database table. These
tuples are extracted and put into individual lists. So I have lists that
look like this: [1, 2, 3, 4, 5]. When I concatenate lists, I end up with a
list of lists that looks like this: [[1, 2, 3. 4, 5]. [6, 7. 8, 9. 10]].
Then, I
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