[ncl-talk] generate_sample_indices without replacement

[Sri nandini]

Hello dear ncl-users,

I would like to know how to properly code for selecting 40 random 
ensemble from a 100 ensembles of my data.

I wonder if someone could help me with this code? My original data is 
[time | 240] x [ens | 100] x [lat | 180] x [lon | 360]

   f     = addfile ("temperature_data.nc", "r")
   T2m    = f->temp

   printVarSummary(T2m)
   dimx = dimsizes(T2m)
   ntim = dimx(0)          ; 240- time dimension
   nens = dimx(1)          ; 100- ensemble dimension
   nlat = dimx(2)            ; 180- lat
   mlon = dimx(3)          ; 360- lon

   T2m at _FillValue = -9.96921e+36

   ; randomly select 40 members from 100 members without replacement
   ; define a new variable dimensions

   n=40
   rcp_40=new((/ntim,n,nlat,mlon/),typeof(rcp45_anom))
   copy_VarCoords(rcp45_anom(:,0,:,:),rcp_40(:,0,:,:))    ; Copy metadata
   printVarSummary(rcp_40) ==>Dimensions and sizes:    [time | 240] x 
[40] x [lat | 180] x [lon | 360]

   Coordinates:
             time: [1192152..1366728]
             lat: [-89.5..89.5]
             lon: [   0.. 359]

   do j= 0,n-1
   iwo = generate_sample_indices( n, 0 )
   rcp_40(:,j,:,:) = T2m(:,iwo,:,:)  ====>error here fatal:VarVarWrite: 
Number of dimensions on left hand side does not match right hand side

   end do
   printVarSummary(rcp_40)

Could someone help me in this code?

Best

Sri