Re: looping over panel plots is very slow

Hi folks,

Julia wrote to me offline and gave me permission to share her solution here.

The problem was a “new” statement that was creating 250 “graphic” objects. She really only needs five at a time (for the panel plot), so she wrote the code so that only 5 “graphic” objects are created at a time. This sped things up “remarkably” as she put it.

—Mary

On Jan 28, 2014, at 8:21 AM, Julia Bethke <julia.bethke@anemos.de> wrote:

>
> Dear all,
>
> I have a ncl code, in which I have roughly 50*5 plots which I want to
> plot alltogether in a pdf with gsn_panel.
> I am plotting 5 plots on one page, resulting in 50 pages. For this, I am
> looping over gsn_panel.
> The code works fine for a small amount of pages, but it takes VERY long
> for this high number of pages.
>
> Is there any chance to reduce the running time of the code?
>
> As the code is rather long and also refers to other functions defined in different codes, I only send the relevant code snippet, where I loop over the panel plots.
> Secondly, I attach a simplified code, which is ready to run. However, here the looping works quite fast. Therefore, I guess the slowing down has something to do with all the indexing within the loop in the original code.
>
> Here is the code snippet from my original code to illustrate the problem:
>
> ----------------------------------------------------------------------------------
> ; calculate page number
> n_pages = n_total
>
> ;---set panel resources
> panel_res = True ; specify desired panel mods
>
> panel_res@gsnFrame = False ; Don't advance frame. because add labelbar
> panel_res@gsnMaximize = True
> panel_res@gsnPaperOrientation = "portrait"
>
> panel_res@gsnPanelCenter = False ; don't center the plots
>
> tx3Res = True
> tx3Res@txJust = "CenterLeft"
>
> gsRes = True ; set polyline resources
> gsRes@gsLineThicknessF = 3.0 ; Extra thick lines
>
>
> if (nd .eq. 4) ; 4 plots on one page --> change legend position
> xleg = (/ (/0.90,0.92/), (/0.90,0.92/), (/0.90,0.92/), (/0.90,0.92/) /)
> yleg = (/ (/0.47,0.47/), (/0.44,0.44/), (/0.41,0.41/), (/0.38,0.38/) /)
> tx3Res@txFontHeightF = 0.013 ; Font Height for legend labels
> else
> xleg = (/ (/0.68,0.70/), (/0.68,0.70/), (/0.68,0.70/), (/0.68,0.70/) /)
> yleg = (/ (/0.11,0.11/), (/0.08,0.08/), (/0.05,0.05/), (/0.02,0.02/) /)
> tx3Res@txFontHeightF = 0.013 ; Font Height for legend labels
> end if
>
> xtxt = (/ xleg(0,1)+0.01, xleg(0,1)+0.01, xleg(0,1)+0.01, xleg(0,1)+0.01 /)
> ytxt = (/ yleg(0,0), yleg(1,0), yleg(2,0), yleg(3,0) /)
>
>
> ;---panel plot, how many plots on one page in x and y direction?
> if (nd .ge. 5)
> panel_ny = 3
> else
> panel_ny = 2
> end if
>
> panel_mx = 2
>
>
> do i = 0, n_pages-1
> print(round(int2flt(i)/n_pages*100,2) + " % of panel created")
>
> panel_res@txString = "Wind roses " + position_name(ind_total(i)) + \
> " (" + height_dir_model_korrel( ind_total(i) ) + " m)" + "~C~" +\ ;~C~ forces a line break: ~I~ writes the letters in indexal size
> "~I~" + time_strings_post_selection(0) + " - " +time_strings_post_selection(dim_selection-1) ; + model_name + case_number
>
> gsn_panel(wks, plot(:,ind_total(i)), (/ panel_ny, panel_mx /), panel_res)
>
> do j = 0, nd-2 ; legend for circles
> gsRes@gsLineColor = colors(j)
> gsn_polyline_ndc(wks,xleg(j,:),yleg(j,:),gsRes)
> end do
>
> gsn_text_ndc(wks,plot_name(:nd-2),xtxt(:nd-2),ytxt(:nd-2),tx3Res)
>
> gsn_labelbar_ndc(wks,nbar,labels,0.1,0.98,lbres) ; add labelbar
> frame(wks)
> delete(panel_res@txString)
> end do
>
> ----------------------------------------------------------------------------------------
>
> And here is the simplified code, which is ready to run:
> ----------------------------------------------------------------------------------------
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>
> begin
> outpath = ; to be defined
>
>
> x = ispan(0,10,1)
> y = ispan(0,10,1)
>
> plot = new( (/5,50/), graphic )
>
> fn = outpath + "panel_loops_test"
> wks = gsn_open_wks("pdf", fn)
>
> res = True
> res@gsnDraw = False
> res@gsnFrame = False ; do not advance the frame
>
> do i = 0,49
> do j = 0,4
> plot(j,i) = gsn_csm_xy(wks,x,y,res)
> end do
> end do
>
> ; draw panels
> n_pages = 50
>
> panel_res = True ; specify desired panel mods
>
> panel_res@gsnFrame = False ; Don't advance frame. because add labelbar
> panel_res@gsnMaximize = True
> panel_res@gsnPaperOrientation = "portrait"
> panel_res@gsnPanelCenter = False ; don't center the plots
>
> do i = 0,n_pages-1
> gsn_panel(wks, plot(:,i), (/ 3, 2 /), panel_res)
> frame(wks)
> end do
>
> end
> ---------------------------------------------------------------------------------------------------
>
> Any help is appreciated very much! Thank you!
>
> Best regards,
> Julia
>
>
>
>
>
>
>
>
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Received on Fri Jan 31 09:05:28 2014