gnuplot-beta

Re: [Gnuplot-info] plot and splot with vectors

[<br...@ph...>]

Donald J Bindner wrote:
> On Sat, Mar 25, 2006 at 06:44:32PM +0100, Hans-Bernhard Br?ker wrote:
>> Donald J Bindner wrote:
>>> vec.dat:
>>> 0 0 1 1
>>> I tried to plot it with:
>>> plot "vec.dat" w vec
>>> It works in my older version, but in the CVS pull, there is no
>>> arrow head.
>> Yep, that's a bug alright.  I'll investigate.

I did some investigating in the meantime.  Turns out this is an utter 
mess, created by about 4 separate attempts at getting option parsing for 
'with vectors' to work piled on top of each other.

The core problem is that the '{s}plot' parser now only initializes the 
relevant data structure for the arrows in a part of the 'while still 
some command-line text left to parse' that is never reached in the
above case.  For gnuplot-beta readers: default_arrow_style() is never 
called if "with vectors" is the last thing on the plot commands line, 
and "arrow_parse()" doesn't initialize anything either.

Re: [Gnuplot-info] plot and splot with vectors

[Lars H. <lhe...@us...>]

> I did some investigating in the meantime.  Turns out this is an utter 
> mess, created by about 4 separate attempts at getting option parsing for 
> 'with vectors' to work piled on top of each other.
> 
> The core problem is that the '{s}plot' parser now only initializes the 
> relevant data structure for the arrows in a part of the 'while still 
> some command-line text left to parse' that is never reached in the
> above case.  For gnuplot-beta readers: default_arrow_style() is never 
> called if "with vectors" is the last thing on the plot commands line, 
> and "arrow_parse()" doesn't initialize anything either.

 {s}plot needs to be moved to table-based parsing to be brought in line
 with the rest of the code, see the comments in tables.c.

Re: [Gnuplot-info] plot and splot with vectors

[Ethan A M. <merritt@u.washington.edu>]

On Monday 27 March 2006 05:06 am, Hans-Bernhard Br=F6ker wrote:
> Donald J Bindner wrote:
> >>> plot "vec.dat" w vec
> >>> It works in my older version, but in the CVS pull, there is no
> >>> arrow head.
>=20
> I did some investigating in the meantime.  Turns out this is an utter=20
> mess, created by about 4 separate attempts at getting option parsing for=
=20
> 'with vectors' to work piled on top of each other.
>=20
> The core problem is that the '{s}plot' parser now only initializes the=20
> relevant data structure for the arrows in a part of the 'while still=20
> some command-line text left to parse' that is never reached in the
> above case.

I won't try to defend the "utter mess", but I think this particular
failure was introduced when we removed the initialization code from
all the <foo>_parse() routines so that successive calls were=20
incremental.  The 2D and 3D plot structures should properly have
their corresponding fields initialized to something reasonable.
Such initialization certainly can't hurt, and I'll add it to the
respective allocation routines cp_alloc() and sp_alloc().

This may actually allow us to remove some of the "utter mess", but
I won't do that without further inspection or testing.

=2D-=20
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742