[ncl-talk] Function return
Prashanth Bhalachandran
prashanth.bhalachandran at gmail.com
Sat Oct 14 14:13:41 MDT 2017
Dear Alan,
Unfortunately, I get a series of fatal errors if I don’t define them apriori.
fatal:Undefined identifier: (speed) is undefined, can't continue
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 32 in file varcalc.ncl
fatal:Undefined identifier: (latvals) is undefined, can't continue
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 33 in file varcalc.ncl
fatal:Undefined identifier: (lonvals) is undefined, can't continue
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 34 in file varcalc.ncl
fatal:Undefined identifier: (speed) is undefined, can't continue
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 36 in file varcalc.ncl
fatal:Undefined identifier: (coord) is undefined, can't continue
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 37 in file varcalc.ncl
fatal:Undefined identifier: (coord) is undefined, can't continue
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 38 in file varcalc.ncl
fatal:Variable (latvals) is undefined
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 42 in file varcalc.ncl
fatal:Undefined identifier: (wnout) is undefined, can't continue
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 43 in file varcalc.ncl
fatal:Undefined identifier: (wnout) is undefined, can't continue
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 44 in file varcalc.ncl
fatal:Variable (var0) is undefined
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 45 in file varcalc.ncl
fatal:Variable (var1) is undefined
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 46 in file varcalc.ncl
> On Oct 14, 2017, at 12:44 PM, Alan Brammer <abrammer at albany.edu <mailto:abrammer at albany.edu>> wrote:
>
> > I don’t know what my dimensions of wnout will be. Will it be a 251x251x73 array?
>
> It will be a list, there won't be array dimensions. You do not need to define wnout before hand.
> likewise, you do not need to define var0 or var1 before hand.
>
> e.g.
>
>
> 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
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
> ;; this section wasn't really needed
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
> 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]
>
> printVarSummary(var0)
> printVarSummary(var1)
>
> ;;;;;;;;;;;;;;;;;;;;;; Write to a netcdf file ;;;;;;;;;;;;;;;;;;
>
> ;;;; I do not think the lines that were here will work.
>
> On Sat, Oct 14, 2017 at 10:26 AM, Prashanth Bhalachandran <prashanth.bhalachandran at gmail.com <mailto:prashanth.bhalachandran at gmail.com>> wrote:
> 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 <http://f2.nc/>")
> ncdf = addfile("$f1_$f2.nc <http://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 <tel:+46%2031%20786%2049%2001>
>> 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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