[ncl-talk] Slow code

[Michael Notaro]

Thanks for your email.


Actually, this is the main part slowing me down, not the top part of the code with the addfiles.


cnt=0
do id=0,30
  daily(:,:,:,:,id)=dim_avg(data(:,:,:,:,cnt:cnt+23)) ; convert hourly to daily data     ***** THIS PART IS SLOW *****
  cnt=cnt+24
end do

Any way to perform this task quicker?

Michael






Michael Notaro
Associate Director
Nelson Institute Center for Climatic Research
University of Wisconsin-Madison
Phone: (608) 261-1503
Email: mnotaro at wisc.edu


________________________________
From: Guido Cioni <guidocioni at gmail.com>
Sent: Tuesday, January 12, 2016 8:57 AM
To: Michael Notaro
Cc: ncl-talk at ucar.edu
Subject: Re: [ncl-talk] Slow code

Everyone here will tell you that using loops in NCL it's not efficient :)
But from my experience I think that the main thing slowing you down is that you are using addfile at every iteration.
Does creating a whole file and reading that in the beginning would change what you are trying to compute?

Guido Cioni
http://guidocioni.altervista.org
[http://guidocioni.altervista.org/nuovosito/wp-content/uploads/2015/10/Screenshot.png]<http://guidocioni.altervista.org/>

Guido Cioni<http://guidocioni.altervista.org/>
guidocioni.altervista.org
Le stazioni sono state riparate ed i dati vengono nuovamente aggiornati in tempo reale. Purtroppo a causa di numerosi malfunzionamenti i dati pluviometrici di Pisa e ...



On 12 Jan 2016, at 15:35, Michael Notaro <mnotaro at wisc.edu<mailto:mnotaro at wisc.edu>> wrote:

Does anyone have a recommendation to speed up my code?
It's been running for a day now.  I put asterisks next to the real slow loop.
Basically, that part is converting a large array of hourly data into daily data.
Thanks, Michael



mns=(/"01","02","03","04","05","06","07","08","09","10","11","12"/)
ndays=(/31,28,31,30,31,30,31,31,30,31,30,31/)

data=new((/141,217,20,12,744/),float) ; hourly data
data at _FillValue=1e+35
data=1e+35

cnt=0
do iyr=0,19
  do im=0,11
    prefix=(1980+iyr)+""+mns(im)
    b=addfile("/volumes/data1/yafang/Downscaling/ACCESS1-0/historical/output/ACCESS_SRF."+(1980+iyr)+""+mns(im)+"0100.nc","r") ; read hourly SRF data
    iy=b->iy
    jx=b->jx
    xlat=b->xlat
    xlon=b->xlon
    snow=b->snv ; liquid equiv of snow on ground
    dims=dimsizes(snow)
    nt=dims(0)
    data(:,:,iyr,im,0:nt-1)=snow(iy|:,jx|:,time|:)
    delete(snow)
    delete(b)
    delete(dims)
    cnt=cnt+1
  end do
end do
data at _FillValue=1e+20

daily=new((/141,217,20,12,31/),float) ; daily data per month
daily at _FillValue=1e+35
daily=1e+35

cnt=0
do id=0,30
  daily(:,:,:,:,id)=dim_avg(data(:,:,:,:,cnt:cnt+23)) ; convert hourly to daily data     ***** THIS PART IS SLOW *****
  cnt=cnt+24
end do

delete(data)




Michael Notaro
Associate Director
Nelson Institute Center for Climatic Research
University of Wisconsin-Madison
Phone: (608) 261-1503
Email: mnotaro at wisc.edu<mailto:mnotaro at wisc.edu>
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