function fsfvp,pp,noisy=noisy

; Purpose: compute stream function and velocity potential on a sphere
; Category pp fortran
; Inputs: 
;	pp - vector of (u,v) components of wind
; Outputs:
; 	[returns] - vector of (sf,vp)
;		sf: stream function (rot_ wind=curl(sf))
;		vp: velocity potential (div_ wind=grad(vp))
; Note: this routine uses SPHEREPACK to do the work.
;       see ~wmc/wave/pros/sfvp1/index.html for more info
; The routine will work on alphas ONLY

dir='/users/icd/wmc/wave/pros/sfvp1/'
rm='rm fort.51 2> /dev/null; '

exe='sfvp1.'+!version.os+'.exe'

; We'll put the result here
pp1=pp

; First, prepare the data file for the prog
x=xc(pp(0),/arr)
y=yc(pp(0),/arr)
openw,lun,/get,'fort.52'
printf,lun,pp(0).lbnpt,pp(0).lbrow
; *** Note negative on pp(1) - spherepack uses opposite sign convention...
for i=0,pp(0).lbrow-1 do for j=0,pp(0).lbnpt-1 do printf,lun,pp(0).data(j,i),-pp(1).data(j,i)
close,lun
free_lun,lun

if (keyword_set(noisy)) then begin
  print,'Written data file fort.52:'
  spawn,'ls -l fort.52'
endif

; Now run stoat
cmd=rm+dir+exe
if (keyword_set(noisy)) then print,'About to spawn: '+cmd
spawn,cmd,junk
if (keyword_set(noisy)) then print,junk

; Read in results
data=readfromfile('fort.51')
pp1(0).data=data(0,*)
pp1(1).data=data(1,*)

; And thats it!
return,pp1
end