Basis -- interactive driver for NCAR

From: P. Dubois (dubois AT unknown)
Date: Sun Jun 18 1995 - 21:35:25 MDT


The recent announcement about NCAR 4.0 reminds me that I may never have
made this announcement to this mailing list; if so I apologize. Since
January 1995 Basis has been available for free release.

Basis is a system for developing computer programs in Fortran, with the
special property that an full interactive programming language,
the Basis Language, is the user interface; this language knows the
subroutines, functions, and common block variables in the compiled Fortran.
So the user can set variables, execute code, and print or plot the
variables. Naturally, variables can be created in the language. It
resembles an array Fortran:

        real x=iota(200), y = sqrt(x**2 + 3 * x + 2)
        plot y x color=red

creates an array x consisting of the first 200 integers, calculates an
array y from it, and plots y vs. x in red. This plot would have
worked equally well if x and y were arrays in common blocks instead of
creating them from the interpreter.

The basic architecture is a package architecture, so that a full Basis
application contains zero or more additional packages. Several packages
are available for reuse in any code. In particular, the ezn package is
loaded by default. It contains an interactive driver for NCAR Graphics,
including commands for plotting curves, text, labels, contours, surfaces,
etc. It can be combined with ATC-GKS, a commercial GKS, for direct
postscript output and a better X-Windows driver than comes with NCAR (IMHO).
It does not contain an interface to the earth-map contour stuff a lot
of you do.

Since Basis is a full language, and includes facilities for reading and
writing text files or files of its own input, the program "basis", which
consists of just the EZN package with a few added packages such as FFTs
and SVDs, can be used as an interactive NCAR driver, without creating
your own Fortran program. Or, you can combine this with your own
processing routines. Some limited C/C++ support is available also.
EZN contains extensive abilities for customization of the pictures.

Basis is available for HP, Sun/SunOs, Sun/Solaris, SGI (regular and Power
Challenge), DEC (64 bit), and IBM workstations, Meiko, Cray YMP, Cray C90.
Basis is available at NERSC.

You get it from ftp-icf.llnl.gov, directory pub/basis. The WWW site is:

http://www-phys.llnl.gov/X_Div/htdocs/basis.html

This contains further info, the complete six-volume manual set (#1 is
a tutorial for users) which is searchable by keyword and hypertexted to
the index. Volume 3 (EZN) contains sample pictures.

Basis was begun in 1984 and has been used in well over a hundred
significant applications. It is used in Lasnex. the main LLNL ICF target
design code. Support is not promised to those outside LLNL (unless they pay!)
but usually questions to support AT unknown are cheerfully answered.

Bon appetit,

Paul F. Dubois



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