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Re: array concatenation and optimization [message #26777]

Thu, 27 September 2001 00:25

R.Bauer
Messages: 1424
Registered: November 1998

Senior Member

Sean Raffuse wrote:
>
> Hello.
>
> I am trying to read a bunch of data from a file to a structure array. I'm
> not sure many data entries the file will have until I have read it and so I
> am increasing the size of the structure array after reading each line. I do
> this by concatenating.
>
> adp_struct_single is the structure as a "scalar"
> adp_struct is the array
>
> I concatenate like so:
> adp_struct =[adp_struct, adp_struct_single]
>
> This is working but it has increased the processing time of my loop by an
> order of magnitude. Is there a better way to do this? Is there a reason
> this is so slow?
>
> Thanks in advance.
>
> -Sean Raffuse

Dear Sean,

if you are able to count in str by e.g. a special sign
how many times you have to repeat the structure then
I believe you can read with reads the whole file
at once.

A similiar mehtod I am using in my read_data_file for ASCII data.

pro read_my_data,filename

OPENR, lun, filename[0], /GET_LUN,error=err
IF err NE 0 THEN GOTO, help_open
stats = FSTAT(lun)

data=make_array(stats.size,/byte)
read_u,lun,data

FREE_LUN, lun

str=bytes2strarr(data)

reads,str,structure

end

This routines from our library may be interesting you.

http://www.fz-juelich.de/icg/icg1/idl_icglib/idl_source/idl_ html/dbase/download/bytes2strarr.tar.gz
http://www.fz-juelich.de/icg/icg1/idl_icglib/idl_source/idl_ html/dbase/download/read_data_file.tar.gz

regards

Reimar

--
Reimar Bauer

Institut fuer Stratosphaerische Chemie (ICG-1)
Forschungszentrum Juelich
email: R.Bauer@fz-juelich.de
http://www.fz-juelich.de/icg/icg1/
============================================================ ======
a IDL library at ForschungsZentrum Juelich
http://www.fz-juelich.de/icg/icg1/idl_icglib/idl_lib_intro.h tml

http://www.fz-juelich.de/zb/text/publikation/juel3786.html
============================================================ ======

read something about linux / windows
http://www.suse.de/de/news/hotnews/MS.html

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[Message index]

		Re: array concatenation and optimization By: R.Bauer on Thu, 27 September 2001 00:25
		Re: array concatenation and optimization By: alt on Wed, 26 September 2001 22:05
		Re: array concatenation and optimization By: Andrew Cool on Wed, 26 September 2001 16:49
		Re: array concatenation and optimization By: Pavel A. Romashkin on Wed, 26 September 2001 14:51
		Re: array concatenation and optimization By: Brian Jackel on Wed, 26 September 2001 14:29
		Re: array concatenation and optimization By: Paul van Delst on Wed, 26 September 2001 12:59
		Re: array concatenation and optimization By: R.G.S. on Wed, 26 September 2001 12:22
		Re: array concatenation and optimization By: Craig Markwardt on Thu, 27 September 2001 09:34

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