Re: looping over panel plots is very slow

Hi Julia,

Thanks for the nice explanation of your problem.

First, what version of NCL are you running?

 ncl -V

How big is the data that you are plotting? Can you send a sample graphic?

I don't think the issue is with gsn_panel per se, but likely with something else in the loop, like adding the text and or labelbar.

Since the simple code didn't really illustrate the problem, let's try to debug your original code.

Here are some things to try:

1. String creation in NCL can be a memory hog if you do a lot of them.

Therefore, I'm a little suspicious that this line might be causing grief:

> 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

Try commenting out this line only and see if it makes a difference.

2. Comment out all the code that adds the legends, text and labelbars, so you are just doing the gsn_panel call.

I want to see if this speeds things up. If it does, then uncomment the various pieces one at a time, running the script each time, to see if there's a noticeable slow down.

3. Try using "PS" instead of "PDF".

If none of this points to the problem, then would you be able to provide your full script and data?

--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 Wed Jan 29 13:40:46 2014