Portable version of igb

igb1y2k.f from /reanl2/codes_j916/fcst/

changes
   f77 syntax
   
   no longer requires logical and real to be same size
     (separated rowsep)

linux, aix:  requires larger stack

----------------------------------------------
	Compiling

linux: make

----------------------------------------------

	Making an isentropic analysis

$ igb.sh spectral_sigma_file grib_isentropic_analyses


Note: on linux (x386), the spectral_sigma_file must be a little-
	endian f77 IEEE file (4 byte reals).
      on AIX, the spectral_sigma_file must be a big-endian
	f77 IEEE file (4 byte reals).

Reanalysis prior to May 2000: the files are in COS-blocked (UNICOS)
IBM-S370 4 byte reals.  You must run a program to convert it to
big/little endian f77 IEEE files.

Reanalysis (R1) model: the AIX version of the model produces
	sigma files with big-endian f77 IEEE file with 8 byte reals.  
	All sigma files are immediately converted to 4 byte reals.

Reanalysis archive:  f77 big-endian IEEE fiels with 4 byte reals.
	On linux, the files must be byte swapped to make them
	little endian.  Since the reals and integers are all 4 bytes,
	the program is fairly trivial.  (A reasonably fast swap
	program is available on request.)


Testing:

	$ igb.sh sig.linux theta.analysis

	The GRIB file, "theta.analysis" should be similar to i.grb.



	


