| Data elimination from array [message #51799] |
Fri, 08 December 2006 09:07  |
StevenM
Messages: 9
Registered: June 2006
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Junior Member |
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Firstly, thanks to those of you who have replied to my posts, the
replies have been very helpful and I really appreciate the time that
has been taken on them.
I am trying to re-organise an array of numbers into 4 new arrays. The
array has 21446656 data points, and I would like to split it up into
four arrays of 5361664 data points. I would like the first 1792 data
points in the first new array, the second 1792 data points in the
second new array and so on. I would then like for the 5th set of 1792
data points (ie starting at data point 8959) to be put in the first new
array and so on.
To make this a bit clearer here is an example
array{0,12,14,16,22,43,12,35,67,88,12,11}
would become
array1{0,22,67}
array2{12,43,88}
array3{14,12,12}
array4{16,35,11}
thanks in advance
Steven
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| Re: Data elimination from array [message #51924 is a reply to message #51799] |
Sat, 09 December 2006 16:08  |
Michael Galloy
Messages: 1114
Registered: April 2006
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Senior Member |
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Braedley wrote:
> And after some optimizations of your code, Mike, it's on par with mine,
> so I offer up the choice to you, Steven.
OK, I took out all the repetitive calls to N_ELEMENTS and fixed the bugs
on array2, array3, array4 which were all identical to array1.
I think the only real difference is stride notation versus creating an
index array.
array = findgen(21446656)
nlen = 1792
n = n_elements(array)
r = reform(array, nlen, n / nlen)
array1 = reform(r[*, 0:*:4], n / 4)
array2 = reform(r[*, 1:*:4], n / 4)
array3 = reform(r[*, 2:*:4], n / 4)
array4 = reform(r[*, 3:*:4], n / 4)
Mike
--
www.michaelgalloy.com
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| Re: Data elimination from array [message #51929 is a reply to message #51799] |
Fri, 08 December 2006 18:55 |
Braedley
Messages: 57
Registered: September 2006
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Member |
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And after some optimizations of your code, Mike, it's on par with mine,
so I offer up the choice to you, Steven.
Braedley
Braedley wrote:
> Yeah, it just doesn't look as clear to me (plus, I think you still have
> an error in there). Mine is also a fair amount faster on my machine
> (AMD 64 X2 4800+, IDLv6.2). It does provide the correct result.
>
> Braedley
>
> mgalloy@gmail.com wrote:
>> Bob Crawford wrote:
>>> On Dec 8, 3:45 pm, "Braedley" <mike.braed...@gmail.com> wrote:
>>>> Except that it doesn't work.
>>>
>>> What doesn't work? Wox's code? It worked when I tried it.
>>
>> Mine original code doesn't work (or it only works for the case the
>> length of each "block" is 1).
>>
>> I think this should be more general:
>>
>> array = findgen(21446656)
>> nlen = 1792
>>
>> r = reform(array, nlen, n_elements(array) / nlen)
>> array1 = reform(r[*, 0:*:4], n_elements(array) / 4)
>> array2 = reform(r[*, 0:*:4], n_elements(array) / 4)
>> array3 = reform(r[*, 0:*:4], n_elements(array) / 4)
>> array4 = reform(r[*, 0:*:4], n_elements(array) / 4)
>>
>> Mike
>> --
>> www.michaelgalloy.com
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| Re: Data elimination from array [message #51930 is a reply to message #51799] |
Fri, 08 December 2006 18:40 |
Braedley
Messages: 57
Registered: September 2006
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Member |
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Yeah, it just doesn't look as clear to me (plus, I think you still have
an error in there). Mine is also a fair amount faster on my machine
(AMD 64 X2 4800+, IDLv6.2). It does provide the correct result.
Braedley
mgalloy@gmail.com wrote:
> Bob Crawford wrote:
>> On Dec 8, 3:45 pm, "Braedley" <mike.braed...@gmail.com> wrote:
>>> Except that it doesn't work.
>>
>> What doesn't work? Wox's code? It worked when I tried it.
>
> Mine original code doesn't work (or it only works for the case the
> length of each "block" is 1).
>
> I think this should be more general:
>
> array = findgen(21446656)
> nlen = 1792
>
> r = reform(array, nlen, n_elements(array) / nlen)
> array1 = reform(r[*, 0:*:4], n_elements(array) / 4)
> array2 = reform(r[*, 0:*:4], n_elements(array) / 4)
> array3 = reform(r[*, 0:*:4], n_elements(array) / 4)
> array4 = reform(r[*, 0:*:4], n_elements(array) / 4)
>
> Mike
> --
> www.michaelgalloy.com
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| Re: Data elimination from array [message #51937 is a reply to message #51799] |
Fri, 08 December 2006 13:59 |
Michael Galloy
Messages: 1114
Registered: April 2006
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Senior Member |
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Bob Crawford wrote:
> On Dec 8, 3:45 pm, "Braedley" <mike.braed...@gmail.com> wrote:
>> Except that it doesn't work.
>
> What doesn't work? Wox's code? It worked when I tried it.
Mine original code doesn't work (or it only works for the case the
length of each "block" is 1).
I think this should be more general:
array = findgen(21446656)
nlen = 1792
r = reform(array, nlen, n_elements(array) / nlen)
array1 = reform(r[*, 0:*:4], n_elements(array) / 4)
array2 = reform(r[*, 0:*:4], n_elements(array) / 4)
array3 = reform(r[*, 0:*:4], n_elements(array) / 4)
array4 = reform(r[*, 0:*:4], n_elements(array) / 4)
Mike
--
www.michaelgalloy.com
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