How to boost performances of NCL scripts?

Hello to everyone,

I would like to boost performances of my ncl scripts to make them faster
and less cpu-consuming.
My script is reading a netcdf file in a native lambert projection grid
and plot temperature contour on a mercator projection. I think
regridding with ndctodata may be one of the reason my script is slow. I
saw that for better performances it could be recommanded to use C
functions and procedures, but I don't know which part of my script could
be put into C routines or if it would help in such case.

Does someone have an idea on optimizing such a script?
Any remark would be very helpful!
Kind regards,
Caroline

-- 
Caroline Serraud - Ingénieur Etudes & Développements
------------------------------------------------------
METEO CONSULT / La Chaine Météo - Groupe Figaro
Département Informatique
Domaine de Marsinval F-78540 Vernouillet, FRANCE
Tél : 01 39 28 1990 - Fax : 01 39 71 85 31
e-mail : cs@meteoconsult.fr
------------------------------------------------------
Toute la météo sur le Web : http://www.meteoconsult.fr
Toute la météo par téléphone : 3201 

;*************************************************
; barb_3.ncl
;
; Concepts illustrated:
; - Drawing colored wind barbs vectors over a cylindrical equidistant map
; - Changing the length of the wind barbs
; - Changing the size of the wind barbs
; - Decreasing the number of vectors drawn
; - Adding a color to an existing color map
; - Using the full color map for colored wind barbs
; - Changing the length of a wind barb tick
; - Changing the distance between wind barb ticks
; - Turning off the vector reference annotation label
; - Drawing a map using the medium resolution map outlines
; - Thinning vectors using a minimum distance resource
;
;************************************************
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
;************************************************
begin
if (.not.isvar("v_file")) then
        print("Le nom du fichier source n'est pas defini")
        exit()
end if
;************************************************
; read in netCDF file
;************************************************
  a = addfile(v_file,"r")
  setfileoption(a,"SuppressClose",False)
  ;************************************************
  ; read in zonal [u] and meridional [v] winds
  ;************************************************
    t = a->TMP_GDS3_HTGL_10(:,:)
    tt = t/10.

    LAT2D= a->g3_lat_0
    LON2D= a->g3_lon_1
    lon2d=LON2D(g3_y_1|:,g3_x_0|:)
    lat2d=LAT2D(g3_y_1|:,g3_x_0|:)

    dimll = dimsizes(lat2d)
    nlon = dimll(0)
    nlat = dimll(1)

    i_lat_min = v_lat_min + 0
    i_lat_max = v_lat_max + 0
    i_lon_min = v_lon_min + 0
    i_lon_max = v_lon_max + 0

;************************************************
; create plot
;************************************************
  wks_type = "ps"
  wks =gsn_open_wks(wks_type,"tempe")

        gsn_define_colormap(wks,"BlWhRe") ; choose color map

        res = True ; plot mods desired

        res@gsnMaximize = True
        res@gsnPaperOrientation = "landscape"
        res@gsnBoxMargin = 0.0

        res@lbLabelBarOn = False

        res@tmXBOn = False ; don't draw axis nor axis labels
        res@tmXTOn = False
        res@tmYLOn = False
        res@tmYROn = False

        res@cnLevelSelectionMode = "ManualLevels"
        res@cnMinLevelValF = -15.
        res@cnMaxLevelValF = 35.
        res@cnLevelSpacingF = 1.
        res@cnFillOn = True ; turn on color for contours
        res@cnLinesOn = False ; turn off contour lines
        res@cnLineLabelsOn = False ; turn off contour line labels
        res@cnFillColors = (/2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78,80,82,84,86,88,90,92,94,96,98,100,102/)
        res@cnInfoLabelOn = False

        res@gsnAddCyclic = False ; regional data

; zoom in on map

   res@mpDataBaseVersion = "RANGS_GSHHS" ; high resolution coastline
   res@mpDataResolution = "FinestResolution"
   res@mpFillOn = False
   res@mpOutlineOn = False
   res@mpPerimOn = False
; res@mpShapeMode = "FixedAspectNoFitBB"

  res@mpProjection = "LambertConformal"
  res@mpLimitMode = "Corners" ; choose range of map
  res@mpLeftCornerLatF = lat2d@corners(0)
  res@mpLeftCornerLonF = lon2d@corners(0)
  res@mpRightCornerLatF = lat2d@corners(2)
  res@mpRightCornerLonF = lon2d@corners(2)
  res@mpLambertParallel1F = lat2d@Latin1 ; ncl adds from grib file
  res@mpLambertParallel2F = lat2d@Latin2 ; ncl adds from grib file
  res@mpLambertMeridianF = lat2d@Lov ; ncl adds from grib file

  res@tfDoNDCOverlay = True
  res@gsnDraw = False
  res@gsnFrame = False

  plot=gsn_csm_contour_map(wks,tt,res)

  getvalues plot
    "vpXF" : x
    "vpYF" : y
    "vpWidthF" : w
    "vpHeightF" : h
  end getvalues
; print("x: " + x + " y: " + y + " w: " + w + " h: " + h)

  ndcx = fspan(x, x + w,nlon)
  ndcy = fspan(y-h,y,nlat)

  eps = 5e-7
  ndcx(0) = ndcx(0) + eps
  ndcx(nlon-1) = ndcx(nlon -1) - eps
  ndcy(0) = ndcy(0) + eps
  ndcy(nlat-1) = ndcy(nlat -1) - eps
 
; print( "calculating lat/lon fields")
  tndcy = new(nlon, float)
  outlat = new((/nlat,nlon/), float)
  outlon = new((/nlat,nlon/), float)

  do i = 0, nlat-1
     tndcy = ndcy(i)
     ndctodata(plot,ndcx,tndcy,outlon(i,:),outlat(i,:))
  end do

  res@gsnAddCyclic = False
  res@sfXArray = outlon
  res@sfYArray = outlat
  res@tfDoNDCOverlay = False

  res@mpProjection = "mercator"
  res@mpLimitMode = "Corners"
  res@mpLeftCornerLatF = i_lat_min
  res@mpLeftCornerLonF = i_lon_min
  res@mpRightCornerLatF = i_lat_max
  res@mpRightCornerLonF = i_lon_max

  plot=gsn_csm_contour_map(wks,tt,res)
  draw(plot)
  frame(wks)

end

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Received on Wed Mar 31 07:45:30 2010