[OctDev] progress meter function

[Rafael L. <ra...@ic...>]

I am almost sure that somebody has already written such a thing, but I just
added comment to my own progress_meter.m function and thought it would be a
interesting addition to OctaveSF.

The file is attached below and I am reproducing the doc string here. Please,
feel free to send comments/patches.  If you do not object, I will add it to
the CVS repository.  I only need to know in which directory.

Enjoy.

## usage:   progress_meter (0, [label, [ncols]])
##          progress_meter (adv)
##
## This function shows a progress meter at stdout and is intended for
## giving visual feedback on the progress of long loop operations.
## A typical call would be like this:
##
##    progress_meter (0, "Computing ... ", 60);
##    N = 2000;
##    for j = 1:N
##      eig (randn (40)); # this is the core of the loop operation
##      progress_meter (j/N);
##    endfor
##
## and the following progress_meter will be shown:
##
##    Computing ... |==                           | - 10%  1m15s
##
## which changes over time, looking later like this:
##
##    Computing ... |============                 | / 42%    43s 
##
## progress_meter should always be called before the loop with the first
## argument equal to 0.  The third optional argument is the number of
## text columns spanned by the display (it defaults to the value of the
## COLUMNS environment variable).  The second optional argument is the
## label that will be shown at the left of the progress meter display.
##
## The other fields in the display are: a horizontal bar giving a
## pictorial indication of the advancement, a "flipping clock", a
## indication of percentage completed, and an estimated time of
## completion.
## 
## When calling progress_meter inside the loop, only one argument should
## be given, which is the amount of advancement.  Its is equal to 0 at
## the beginning and must reach 1 at the end of the loop.
##
## Implementation notes:  
##
## 1) A number of global variables are defined in order to keep the
##    internal state of the meter.  All Their names start with
##    "progress_meter_".  The user must avoid to mess with them in her
##    code. 
## 2) This implementation relies on Unix specificities, like the
##    getenv("COLUMNS") call and the use of "\r" in printf().  For now,
##    progress_meter has only be tested in Linux.
## 3) The estimated time of completion is noisy, since it is computed
##    from one iteration to another, with tic() and toc() calls.  

-- 
Rafael Laboissiere