Is there a bug with fbinrecwrite or fbinrecread

Dear all:

It seems there is bug in fbinrecwrite or fbinrecread.

Here is the test main idea:
step 1: read netcdf file and get two variables data
step 2: printMinMax values of variables
step 3: using fbinrecwrite to write binary file
step 4: using fbinrecread to read binary file
step 5: printMinMax values of the new two variables

But I compared the Min and Max values between the original data and
new data read from binary file are different.

Original Min and Max values:
Monthly Longterm Mean of U-Wind: min=-37.2069 max=95.8738
Monthly Longterm Mean of V-Wind: min=-33.7934 max=32.8907

New Min and Max values read from binary file
u-wind Min and Max values read from ./wind.mon.ltm.bin are
min=-37.2069 max=81.1241
v-wind Min and Max values read from ./wind.mon.ltm.bin are
min=-36.9928 max=95.8738

Also in my script I output only variable to binary file and read it,
there is no problem.
u-wind Min and Max values read from ./uwind.mon.ltm.bin are
min=-37.2069 max=95.8738

So Could anyone check what is going when outputting two variables?

Thanks

Guangshan

;================================================;
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
;================================================;
;load external functions should be included path;
;external function_name "./function_name.so"
;================================================;
begin
;================================================;
;The binary file will be the same as a one open via fortran's open
statement:
;
; open(..., form="unformatted", [,access="sequential"] ) ;
sequential is default

uwind_file = addfile("uwnd.mon.ltm.nc","r")
vwind_file = addfile("vwnd.mon.ltm.nc","r")

; data can be download from
;http://www.esrl.noaa.gov/psd/cgi-bin/db_search/DBSearch.pl?Variable=U-
; Wind&Dataset=CDC+Derived+NCEP+Reanalysis+Products+Pressure+Level
; http://www.esrl.noaa.gov/psd/cgi-bin/db_search/DBSearch.pl?Variable=V-
; Wind&Dataset=CDC+Derived+NCEP+Reanalysis+Products+Pressure+Level

lat = uwind_file->lat(::-1)
print(lat)
lon = uwind_file->lon
lev = uwind_file->level
time = uwind_file->time

nlat = dimsizes(lat)
nlon = dimsizes(lon)
nlev = dimsizes(lev)
ntime = dimsizes(time)

; make sure lat from -90. 90.
uwind = uwind_file->uwnd(:,:,::-1,:)
vwind = vwind_file->vwnd(:,:,::-1,:)

printMinMax(uwind,True)
printMinMax(vwind,True)

  setfileoption("bin","WriteByteOrder","BigEndian")

path = "./wind.mon.ltm.bin"

do itime=0,ntime-1

   do ilev=0,nlev-1
    fbinrecwrite(path,-1,(/uwind(itime,ilev,:,:)/))
   end do

   do ilev=0,nlev-1
    fbinrecwrite(path,-1,(/vwind(itime,ilev,:,:)/))
   end do

end do

;************************************************************
; note the -1 indicates to just add on to the end of the file
; the (/.../) syntax means output the values only with no meta
; data
;************************************************************

path1 = "./uwind.mon.ltm.bin"

do itime=0,ntime-1
   do ilev=0,nlev-1
    fbinrecwrite(path1,-1,(/uwind(itime,ilev,:,:)/))
   end do
end do

; read uwind and vwind binary file

   setfileoption("bin","ReadByteOrder","BigEndian")

   rec_dims=(/nlat,nlon/)
   rec_type="float"

   uwnd=new( (/ntime,nlev,nlat,nlon/), rec_type )
   vwnd=new( (/ntime,nlev,nlat,nlon/), rec_type )
   rec_num = 0
   do it=0,ntime-1
     do il=0,nlev-1
       uwnd(it,il,:,:)=fbinrecread(path,rec_num,rec_dims,rec_type )
       rec_num=rec_num+1
     end do

     do il=0,nlev-1
       vwnd(it,il,:,:)=fbinrecread(path,rec_num,rec_dims,rec_type )
       rec_num=rec_num+1
     end do

   end do

   print("u-wind Min and Max values read from "+ path)
   printMinMax(uwnd,True)
   print("v-wind Min and Max values read from "+ path)
   printMinMax(vwnd,True)

; read uwind only binary file
   uwnd_o=new( (/ntime,nlev,nlat,nlon/), rec_type )
   rec_num = 0
   do it=0,ntime-1

     do il=0,nlev-1
       uwnd_o(it,il,:,:)=fbinrecread(path1,rec_num,rec_dims,rec_type )
       rec_num=rec_num+1
     end do

   end do

   print("u-wind Min and Max values read from "+ path1)
   printMinMax(uwnd_o,True)
;================================================;
;================================================;
end

_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk
Received on Thu Oct 29 20:19:18 2009