Provided by: gnudatalanguage_1.0.6-1_amd64 
NAME
gdl - GNU Data Language incremental compiler
SYNOPSIS
gdl [--help] [-h] [--version] [-v] [-V] [[-]-quiet] [-q] [ -arg value ] [ -args ... ] [
-e statement ] [ -pref=/path/to/preferenceFile ] [ batch_file ... ]
DESCRIPTION
gdl is an incremental compiler for the GNU Data Language (GDL). GDL is being developed
with the aim of providing an open-source drop-in replacement for Interactive Data Language
(IDL) (RSI then ITTVIS then Exelis and now Harris Geospatial Solutions, Inc.). It is also
partially compatible with Visual Numerics (VN) PV-WAVE. IDL and PV-WAVE are registered
trademarks of L3Harris and VN, respectively. GDL and its library routines are designed as
a tool for numerical data analysis and visualisation. GDL is dynamically typed,
vectorized and has object-oriented programming capabilities. The library routines handle
numerical calculations, data visualisation, signal/image processing, file input/output
(incl. graphical and scientific data formats such as TIFF, PNG, netCDF, HDF etc) and
interaction with host OS.
For a list of resources on GDL/IDL/PV-WAVE syntax and library routines, see references in
GDL v1.0 JOSS paper: https://doi.org/10.21105/joss.04633
GDL mailing list is maintained at: https://sympa.obspm.fr/wws/info/gdl-announces
A vast part of GDL library routines is implemented using open-source libraries including
GSL, plPlot, and optionally: readline, FFTW, Eigen3, ImageMagick, netCDF, HDF4, HDF5,
PROJ, UDUNITS-2, libps and others.
OPTIONS
--help (or -h)
Show summary of options
--version (or -v, -V)
Show version of program
--quiet (or -quiet, -q)
Suppress welcome messages
-arg value
Tells COMMAND_LINE_ARGS() to report the following argument (may be specified more
than once)
-args ...
Tells COMMAND_LINE_ARGS() to report all following arguments
-e statement
Execute given statement and exit (last occurrence taken into account only, executed
after startup file, may not be specified together with batch files)
-pref=/path/to/PreferenceFile
(only partially working now) setting using external text file few variables
including default preferences (e.g. X11 Windows Size)
--fakerelease version
setting !VERSION.RELEASE to that value. !VERSION.RELEASE is often tested by
procedures to decide whether some function or option should be used. It is
sometimes possible to use this option to fool a procedure that request a specific
value of !VERSION.RELEASE (e.g. atv.pro)
--fussy
signals that all used procedures will adhere with modern IDL, where "()" are for
functions and "[]" are for arrays. This speeds up (sometimes terribly) compilation
but choke on every use of "()" with arrays. Conversion of procedures to modern IDL
can be done with D. Landsman's idlv4_to_v5 procedure. Use environment variable
"GDL_IS_FUSSY" to set up permanently this feature.
Incidentally "being fussy" can help find all places in a procedure that need to be
corrected to have it in the modern IDL format.
--silent
Supresses some messages (mainly "Compiled Module XXX" .)
--sloppy
inverse of fussy above. Sets the traditional (default) compiling option where "()"
can be used both with functions and arrays. Needed to counteract temporarily the
effect of the environment variable "GDL_IS_FUSSY".
--smart-tpool
switch to a mode where the number of threads is adaptive (experimental). Should
enable better perfs on many core machines.
--use-wx
Tells GDL to use WxWidgets graphics instead of X11 or Windows. (nicer plots). Also
enabled by setting the environment variable GDL_USE_WX to a non-null value.
--no-use-wx
Tells GDL no to use WxWidgets graphics, even if env. var. "GDL_USE_WX" is set.
--no-dSFMT
Tells GDL not to use double precision SIMD oriented Fast Mersenne Twister(dSFMT)
for random values. Also disabled by setting the environment variable GDL_NO_DSFMT
to a non-null value.
With dSFMT, although the Mersenne Twister algorithm is the same as in modern IDL,
the values are computed in parallel (hence a speed gain) but the output order is
not the same as IDL. Also, the seed is different. Theses differences should not be
a problem as it is discouraged to interfere with seed values.
The -demo, -em, -novm, -queue, -rt, -ulicense and -vm options are ignored for
compatibility with IDL.
A list of batch files to be executed before entering the interactive
mode (but after executing a startup file, if specified) may be given when not using
the -e option.
FILES
$DATADIR/gnudatalanguage/lib/*.pro
Library routines implemented in GDL. $DATADIR is specified during compilation and
usually translates to /usr/share, /usr/local/share or alike. GDL includes this
directory in its search path unless GDL_PATH or IDL_PATH env. variables are set
(see below).
$HOME/.gdl/history
A file used for storing the history of commands issued in the interactive mode (if
GDL compiled within ReadLine)
ENVIRONMENT
The following environment variables have special meaning to gdl. The GDL_* variant, if
defined, takes precedence over any corresponding IDL_* variant.
GDL_PATH, IDL_PATH
The GDL command (script) search path.
GDL_STARTUP, IDL_STARTUP
A file of commands to be executed on startup.
GDL_TMPDIR, IDL_TMPDIR
A directory in which temporary files may be created.
HOME, SHELL
Variables influencing shell invocations from within GDL (SPAWN procedure and the $
interpreter command). Value of HOME determines as well the location of the GDL
history-file.
PATH Determines search path when spawning child processes using the SPAWN procedure with
the /NOSHELL keyword set.
PYTHONPATH
Influences behaviour of PYTHON procedure and PYTHON() function (available if GDL is
compiled with support for calling Python code)
GDL_MPI
A message to be sent out using MPI_Send before initialization of the interpreter
(available if GDL is compiled with support for MPI)
DISPLAY, XENVIRONMENT
Tell GDL how to connect to the X server
PLPLOT_DRV_DIR
Override the default location of PLplot dynamic drivers.
LC_* The locale-related settings accessible via LOCALE_GET() (GDL always uses the C
locale internally)
GDL_GR_WIN_HEIGHT
Sets the preference for the default height of a Windows(tm) graphic window
GDL_GR_WIN_QSCREEN
if set to true (1) this will prevent the use of the GDL_GR_WIN_HEIGHT and
GDL_GR_WIN_WIDTH preferences and the default dimensions of graphic windows will be
1/4 of the screen dimensions
GDL_GR_WIN_WIDTH
Sets the preference for the default width of a Windows(tm) graphic window
GDL_GR_X_HEIGHT
Sets the preference for the default height of an X11 graphic window
GDL_GR_X_QSCREEN
if set to true (1) this will prevent the use of the GDL_GR_X_HEIGHT and
GDL_GR_X_WIDTH preferences and the default dimensions of graphic windows will be
1/4 of the screen dimensions
GDL_GR_X_WIDTH
Sets the preference for the default width of an X11 graphic window
GDL_WX_BACKEND
can be set to [0,1,2] which will select, respectively, the back-ends 0,1 or 2 of
plplot's old wxWidgets driver (plplot versions < 5.10). Back-end 2 has anti-
aliasing enabled.
GDL_MAPS_DIR
If not automatically found, tells GDL where the maps files (coasts rivers, etc,
used by MAPS_CONTINENTS) are located. These are in Shapefile format and newer
versions can possibly be present on naturalearthdata.com
BUGS
Please report bugs, comments, patches or feature requests at
https://github.com/gnudatalanguage/gdl/
AUTHOR
The primary author of GDL is Marc Schellens <m_schellens@users.sourceforge.net>. A list
of contributors is available in the AUTHORS file shipped with GDL, and on the project
website (see above).
The original version of this manual page was written by Sergio Gelato
<Sergio.Gelato@astro.su.se>. It is currently a part of the GDL package, and is maintained
by the GDL Team.
SEE ALSO
netcdf(3), hdf(1), gsl(3), eigen3, plplot, fftw