=head1 NAME

tela - TEnsor LAnguage

=head1 SYNOPSIS

B<tela>	S<[ B<-v> | B<--verbose> ]> S<[ B<-b> | B<--batch> ]>
	S<[ B<-f> | B<--fast> ]> S<[ B<-s> | B<--silent> ]> S<[ B<-O>[I<level>] ]>
	S<[ B<-e> I<tela-code> | B<--execute> I<tela-code> ]> S<[ I<files> ]>

B<tela> S<B<-V> | B<--version>>

B<tela> S<B<-?> | B<-h> | B<--help>>

=head1 DESCRIPTION

Start B<tela>; first execute I<tela-code>, then each of I<files> in
turn (if any), finally enter interactive mode.

Tela is a numerical computing environment mainly targeted for
numerical simulation pre- and post-processing work.  The language
supports arbitrary rank arrays (hence the name, TEnsor LAnguage), and
has powerful programming capabilities including F90 style vector
notation.  Two- and three- dimensional graphics is implemented by
calling PlotMTV.  For 2D graphics, the SPPC interface is also
available.

The on-line help is intended as the primary source of documentation.
The command S<B<help> I<topic>> gives help on I<topic>, where I<topic>
can be individual reserved words, function names, etc.

=head1 OPTIONS

B<tela> accepts the following options:

=over 8

=item B<-b>, B<--batch>

Quit after executing I<tela-code>, or I<files>.

=item B<-e>, B<--execute> I<tela-code>

Execute Tela expressions I<tela-code>.

=item B<-f>, B<--fast>

Do not source any initialization files; see L<"INITIALIZATION">.

=item B<-O>[I<level>]

Select optimization level.  B<-O0>, the default, means no
optimization.  B<-O>, and B<-O1> enable flat-code optimization.

=item B<-h>, B<-?>, B<--help>

Print help message and exit.

=item B<-s>, B<--silent>

Suppress startup message, MIPS count, and FLOPS count.

=item B<-v>, B<--verbose>

Set verbose execution mode: list tree-codes and flat-codes.

=item B<-V>, B<--version>

Print version number and exit.

=back

=head1 INITIALIZATION

Unless suppressed with the B<-f> or B<--fast> options B<tela> tries to
source the file F<telainit.t> (or just F<telainit> if that
exists).  The sourced files are searched in a directory path, which is
obtained as follows:

=over 4

=item 1.

A compiled-in default, typically
C<"/usr/local/lib/tela/t:/usr/local/lib/tela/ct:/usr/local/lib/tela:.">

=item 2.

If set, the environment variable B<TELAPATH_SYSTEM> overrides
the compiled-in default, or appends to it if it starts with a colon.

=item 3.

Similarly, if set, the environment variable B<TELAPATH> overrides
the previous, or appends to them if it starts with a colon.

=back

The combined effect of the compiled-in default, B<TELAPATH_SYSTEM>,
and B<TELAPATH> can be seen by giving the command B<telapath()> in
Tela.

The standard F<telainit.t> tries to source $HOME/F<.telainit.t>.

=head1 ENVIRONMENT

Besides B<TELAPATH> and B<TELAPATH_SYSTEM>, B<tela> recognizes the
following environment variables: B<TELA_PLOTMTV> specifies the PlotMTV
program to use (default: C<plotmtv>).  The function C<whos()> displays
variables and uses the B<PAGER> (default: C<more>) and B<TELA_SORTER>
(default: S<C<sort> C<-b> C<-f> C<-k> C<1>>) environment variables.

=head1 SEE ALSO

    telakka	Tela extension utility
    ctpp	Tela preprocessor
    plotmtv	Standard associated graphics package
    sppc	Alternative graphics package
    m2t		Matlab to Tela translator

=head1 HISTORY

Tela by S<Pekka Janhunen>; man page by S<Ch. L. Spiel>, 2000-12-7.
