RE: Some matlab stuff

[Ted Harding]

On 15-Sep-99 Beverley Eyre wrote:
> Hey. I'm new to Octave and old to Matlab. I notice that Octave uses
> gnuplot (which I've also used but little) to plot. Can Octave use all
> of gnuplot (i.e. is gnuplot a subset of Octave?) If not, is there
> anything that gnuplot does better than Octave? I'm still going through
> the FAQ's and the online help stuff, so much of the questions that I
> have may be answered there.

Gnuplot is a separate program which octave uses to perform required
plotting.

On UNIX systems, there is a clean mechanism for both programs to be
running at the same time and for octave to pass commands and data through
a "pipe" to gnuplot. Octave doesn't have to use gnuplot, but since octave
has a lot of built-in support for the interface to gnuplot it is easiest
to use gnuplot rather than any other plotting program. In particular,
octave delegates the computation for contouring or hidden-line surface
plotting to gnuplot rather than doing it internally, so any alternative
program would have to have similar capabilities.

If you are running octave on a Windows system then I don't know how
it works, but presumably it is similar.

Octave's interface internally supports gnuplot's most important commands,
and there are mechanisms for sending others directly.

> (still trying to clear a plot. clf doesn't work)

It should be 'clg', not 'clf'. Sure, there is no immediate response to
clg. However, in "hold off" mode, the next 'plot' command clears the plot
window automatically and replaces it with the next plot, so there's no
need for clg to do anything in this mode.

In "hold on" mode, successive plots are added to the current plot. If you
then do 'clg', although there is no immediate response, the next plot
will clear everything plotted so far and plot just the next plot
(remaining in "hold on" mode). Agreed, this is minimal behaviour, but
it's all that's needed.

Ted.

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E-Mail: (Ted Harding) <address@hidden>
Date: 15-Sep-99                                       Time: 20:20:34
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