[ncl-talk] Function return
Prashanth Bhalachandran
prashanth.bhalachandran at gmail.com
Sat Oct 14 08:26:17 MDT 2017
Dear Marston,
Thank you for your response. I will ensure that the missing values are the default ones from NCL. I hope my attaching the code will give you a little more context.
My concern is this : If I am returning two arrays var0 and var01 (please see the red highlighted portions for array dimensions), how will I receive it in the main wrapper script?
That is, if my var0 dimension is : (/251/) and my var01 dimension is (/251,73/), and I return the variable from the function using return([/var0,var01/]), when I collect it in the wrapper script using
wnout = wn01(latvals,lonvals,lat1,lon1,speed),
I don’t know what my dimensions of wnout will be. Will it be a 251x251x73 array? I do know that I want to extract it as:
var0 = wnout[0]
var1 = wnout[1]
CODE
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
load "/scratch/lustreD/s/sbhalach/DATA/func_center.ncl"
load "/scratch/lustreD/s/sbhalach/DATA/func_rtheta.ncl"
a = addfile(filename,"r")
u10 = a->u10
v10 = a->v10
slp = a->slp
;;;;;;;;;;;;;;;;; Constants ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
R = 6371
d2r = atan(1.0)/45; Equivalent of pi/180 - 0.01745329
r2d = 1.0/d2r
toknots = 1.94384
pi = 3.14159
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
latvals = new((/801/),float,1e+30)
lonvals = new((/810/),float,1e+30)
speed = new((/801,810/),float,1e+30)
var01 = new((/251,73/),float,1e+30)
var0 = new((/251/),float,1e+30)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
slpsub = slp(time,0,:,:) ; X is now a 2D array
speed(:,:) = wind_speed(u10(time,0,:,:),v10(time,0,:,:)) * toknots
latvals(:) = u10&lat(0:800)
lonvals(:) = u10&lon(0:809)
coord = center_find(speed(:,:),slpsub)
lat1 = coord[0]
lon1 = coord[1]
;;;;;;;;;;;;;; Find all variables here and store into allvars ;;;;;;;
wnout = wn01(latvals,lonvals,lat1,lon1,speed)
var0 = wnout[0]
var1 = wnout[1]
;;;;;;;;;;;;;;;;;;;;;; Write to a netcdf file ;;;;;;;;;;;;;;;;;;
system("rm -f $f1_$f2.nc")
ncdf = addfile("$f1_$f2.nc","c")
ncdf->allvars = allvars
ncdf->yymmdd = $f1
ncdf->time = $f2
-------------------------------------------------------------------
FUNCTION
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
load "/scratch/lustreD/s/sbhalach/DATA/func_center.ncl"
undef("wn01")
function wn01(latvals:float,lonvals:float,lat1:float,lon1:float,var:float)
local R,d2r,r2d,toknots,pi,delr,Xi,Yi,xo,yo,nearxo,nearyo,ovar,var01,var0,c1,b1,orad,otha,arr,a1,a2,a3,a4,a5,a6,a7,a8,a9,r,weights
begin
R = 6371
d2r = atan(1.0)/45; Equivalent of pi/180 or 0.01745329
r2d = 1.0/d2r
toknots = 1.94384
pi = 3.14159
delr = 12
Xi = new((/810/),float,1e+30)
Yi = new((/801/),float,1e+30)
ovar = new((/251,73/),float,1e+30)
var01 = new((/251,73/),float,1e+30)
var0 = new((/251/),float,1e+30)
c1 = new((/251/),float,1e+30)
b1 = new((/251/),float,1e+30)
orad = ispan(0,1000,delr)
otha = fspan(0,6.283185,73)
arr = new((/3,3/),float,1e+30)
Xi(:) = R *cos(lat1*d2r)*(lonvals(:)-lon1) * d2r
Yi(:) = R *(latvals(:)-lat1) * d2r
do radius=0,250,1
do theta=0,72,1
xo = (radius*delr)*cos((theta*5)*d2r) ; reference points
yo = (radius*delr)*sin((theta*5)*d2r) ; reference points
nearxo = ind_nearest_coord (xo, Xi(:), 0) ;Find the index of the bounds
nearyo = ind_nearest_coord (yo, Yi(:), 0)
if(nearxo .eq. 0 .or. nearxo .eq. 809 .or. nearyo .eq. 0 .or. nearyo .eq. 800) then
ovar(radius,theta) = var(nearyo,nearxo)
else
a1 = var(nearyo+1,nearxo+1)
a2 = var(nearyo+1,nearxo)
a3 = var(nearyo-1,nearxo-1)
a4 = var(nearyo,nearxo+1)
a5 = var(nearyo,nearxo)
a6 = var(nearyo,nearxo-1)
a7 = var(nearyo-1,nearxo+1)
a8 = var(nearyo-1,nearxo)
a9 = var(nearyo-1,nearxo-1)
arr = (/ (/a1,a2,a3/), (/a4,a5,a6/), (/a7,a8,a9/)/) ; Written as nD arrays for visual clarity of neighbors
weights = (/ (/0.0625,0.0625,0.0625/), (/0.0625,0.5,0.0625/), (/0.0625,0.0625,0.0625/)/)
ovar(radius,theta) = dim_avg_wgt(ndtooned(arr),ndtooned(weights),1)
; Give 50% weight to the nearest location and distribute the other 50% equally amongst the neighbours
end if
end do ; Loop over every radius and theta
end do ; End of r-theta loop
do r=0,250,1
var0(r) = 1/(2*pi)*simpeq(ovar(r,:),5.0*d2r) ; Dimension (/251/)
c1(r) = 1/(2*pi)*simpeq(ovar(r,:)*cos(otha),5.0*d2r)
b1(r) = 1/(2*pi)*simpeq(ovar(r,:)*sin(otha),5.0*d2r)
var01(r,:) = var0(r) + (c1(r)*cos(otha)) + (b1(r)*sin(otha)) ; Dimension (/251,73/)
end do
return([/var0,var01/])
end
> On Oct 14, 2017, at 12:42 AM, Marston Johnston <shejo284 at gmail.com <mailto:shejo284 at gmail.com>> wrote:
>
> There is an error in your code: var0 = new((/251/),float,1e+30
> As a preference, I always find it best to use the default FillValues when creating arrays. Read up on missing values/fillvalues on the NCL wedpage.
>
> There is nothing wrong with returning a list from a function, even if the dimensions are different. Why would the dimensions matter?
> This doesn’t seem to be your problem. You have not provided enough information about your code and variable information (printVarSumary) to give a definite answer.
> It seems you need to do some more debugging of your code yourself.
>
> When defining functions, it is good practice to set the define the intrinsic variables as “local” as well as using the “undef” function.
> Using the same name for the variables inside and outside the function, if you are indeed using a function that is properly designed, can mask a bug in your code.
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Marston S. Ward, PhD
> Department of Earth Sciences
> University of Gothenburg, Sweden
> Email: marston.johnston at gu.se <mailto:marston.johnston at gu.se>
> SkypeID: marston.johnston
> Phone: +46-31-7864901
> Only the fruitful thing is true!
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
> From: ncl-talk <ncl-talk-bounces at ucar.edu <mailto:ncl-talk-bounces at ucar.edu>> on behalf of Prashanth Bhalachandran <prashanth.bhalachandran at gmail.com <mailto:prashanth.bhalachandran at gmail.com>>
> Date: Saturday, 14 October 2017 at 03:57
> To: <ncl-talk at ucar.edu <mailto:ncl-talk at ucar.edu>>
> Subject: Re: [ncl-talk] Function return
>
> Hello,
> I have a quick question regarding returning of arrays from functions.
>
> In my code, I have two arrays var0 and var01 that I want to return from my function. Their dimensionalities are as follows:
>
>
> var0 = new((/251/),float,1e+30
> var01 = new((/251,73/),float,1e+30)
>
>
> At present, I am trying to return this using the command :
>
> return([/var0,var01/]) ; Note that the dimensions of var0 and var1 are different.
>
>
> As a result, in my wrapper script, when I receive the variables, it is becoming a confusing task.
>
>
> wnout = wn01(latvals,lonvals,lat1,lon1,speed)
> var0 = wnout[0]
> var1 = wnout[1]
>
>
> The above return procedure is giving out an error since I don’t know how to define the dimensions of wnout. Is there any better way to return two arrays of varying dimensions in NCL?
>
>
> Thank you,
> Prashanth
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