MAKGRD
| 
| 
|
| Latest: MAKGRD v2.0 (20APR18)
[Download]
| 03DEC23
|
Introduction
Part of the RFM handling of Irregular Spectral Grids
(.grd files)
MAKGRD is a Fortran90 program to convert a
user-supplied list
of spectral axis points into the RFM
.grd file format.
General Comments
- A .grd file
contains a series of '1's and '0's on a spectral fine grid
(encoded in groups of 4 as hexadecimal characters):
'1' indicates a fine grid point which
is to be used for the spectral and radiative
transfer calculations when the RFM GRD
Flag is enabled (otherwise the RFM performs calculations at all fine
grid points).
- Generating such a file is non-trivial
(the format comes from the RFM's origins as a tool to support
MIPAS processing), so this program has been written to
to convert a simple list of spectral points in
either wavenumber [cm-1] or frequency [GHz] units.
- The spectral points have to be in monotonically increasing
order, and must all be integer multiples of some
fundamental fine grid spacing, which the user also specifies.
- The default option is to produce an output
.grd
file which
exactly matches the spectral range of the user-supplied points, but the
user has the option of modifying this range (any extension being filled
with '0' values).
Installing makgrd
Download the source code: [makgrd.f90]
Compile with any generic FORTRAN compiler, eg
gfortran makgrd.f90 -o makgrd
Running makgrd
To run the program, type makgrd and respond to the prompts.
A typical run might be
(user responses in bold)
makgrd
R-MAKGRD: Running MAKGRD v2.0
Fundamental resolution: 0.0005 (Note 1)
File containing spectral points: points.txt
(Note 2)
Output spectral range (= 800.0000: 800.8000 [cm-1]): <CR>
(Note 3)
Output .grd file: points.grd
R-MAKGRD: Successful completion
The program should run almost instantaneously.
Notes
- It is assumed that the user-supplied set of irregular grid points represent
a sub-sampling of some underlying regular grid.
- User's file containing the
list of spectral points (see List file, below).
- At this point the user has the option of setting the output file to
maintain the original
spectral range of the supplied grid points, or of adjusting the range.
If extended, the output file will simply be padded with '0's.
List file
The user supplies a set of spectral points in a file with the following
format:
| HEADER | (optional)
|
| NSPC
|
| SPC(1) SPC(2) ..
|
| ... SPC(|NSPC|)
|
| [eof]
|
Where the fields are defined as follows
| Field | Type | Description | Range
|
|---|
| HEADER
| C80
| Comment record
| First character is '!'
|
| NSPC
| I
| No.spectral points (-ve if GHz units)
| | NSPC | > 1
|
| SPC
| D
| Spectral point value
| [cm-1] or [GHz]
|
Type:
I=Integer;
R=Real;
D=Double Precision;
Cn=character string, length n.
Notes
- If the first character of the first record is '!' then this
is interpreted as a comment record and passed to the output file
as the CONFIG record
(see .grd file format). If there is
no initial comment record, the name of the list file is written to the
CONFIG record.
- The first non-comment record should contain just an integer indicating
the number of spectral points to follow. A negative value of NSPC
indicates that the
points are in [GHz], while a positive value indicates [cm-1].
- Then follows the set of spectral points in monotonically increasing
order, read free-format.
Examples
The following is an example of a list of points, actually
just sampling a 0.0005 cm-1 grid at 0.004 cm-1 spacing.
! test data
201
800.00000 800.00400 800.00800 800.01200 800.01600
800.02000 800.02400 800.02800 800.03200 800.03600
800.04000 800.04400 800.04800 800.05200 800.05600
...
800.78000 800.78400 800.78800 800.79200 800.79600
800.80000
This file generates the following output .grd file
! test data
! Created by program makgrd.f90 v2.0
lin
1601 201 800.0000 0.0005
0.0 120.0
80808080808080808080808080808080808080808080808080
80808080808080808080808080808080808080808080808080
80808080808080808080808080808080808080808080808080
80808080808080808080808080808080808080808080808080
80808080808080808080808080808080808080808080808080
80808080808080808080808080808080808080808080808080
80808080808080808080808080808080808080808080808080
80808080808080808080808080808080808080808080808080
8
Error Messages
Fatal error messages may occur if there are I/O errors on the input
or output files, if the spectral points are not multiples of the
fundamental grid, or if the user specifies a modified output range which
is inconsistent with the input data.
Version History
- v2.00 (20APR18)
- Recoded in FORTRAN 90 but, from the user's viewpoint, unchanged.
- v1.00 (23JUL15)
- Original code (F77)