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Re: array concatenation and optimization [message #26784 is a reply to message #26779]

Wed, 26 September 2001 16:49

Andrew Cool
Messages: 219
Registered: January 1996

Senior Member

Brian Jackel wrote:
>
> Hi
>
> This is what I generally do
>
> dat= {struct, a:fltarr(3), b:intarr(4), c:0b} ;example structure
> OPENR,lun,filename,/GET_LUN
> READU,lun,dat ;read one record
> fs= FSTAT(lun) ;look at current file information
> nrec= fs.size/fs.cur_ptr
> IF (fs.size GT 100000000L) THEN BEGIN ;avoid out-of-memory errors
> FREE_LUN,lun
> MESSAGE,'Error- file larger than 100Mbytes, returning'
> ENDIF
> POINT_LUN,lun,0
> data= REPLICATE(dat,nrec)
> READU,lun,data ;read all the data at once
> FREE_LUN,lun
>
> I'm not sure how well this will work with compressed files.
>
> Brian
>
> 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

G'Day,

Under IDL v5.5, the new routine FILE_INFO returns much the same
information as FSTAT, *but* the file doesn't have to be open already!

Nifty.

Andrew Cool

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Phone : 061 8 8259 5740 Fax : 061 8 8259 6673
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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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