gnuplot-py-users Mailing List for Gnuplot.py

Leonardo Milano writes:
> Is there a date-format data type in Python ?. I browsed the docs
> and couldn't find one. Or is there a class for that ?.

There is a package called mx.DateTime or something like that with a
vary capable date class, but unfortunately it is not part of standard
Python.  Standard Python tends to use doubles or tuples to represent
date/times and the time module has lots of routines for manipulating
dates/times.

Michael

--
Michael Haggerty
hag...@jp...

Lothar Birk writes:
> > It looks like you are using a home-cooked extension to Gnuplot.py,
> > so I could only guess what your problem might be.  Possibly the
> > argument that you are passing to gnuplot.__call__ is not a
> > sensible string as it should be.
> 
> Yes it is a crooked extension, which maintains a list of all gnuplot
> commands and allows you to build up a plot command by adding more
> and more curves which finally get plotted into one diagrams.

Just a quick note: you can add PlotItems one after another in the
standard Gnuplot.py by calling Gnuplot.replot() with additional
arguments as documented in _Gnuplot.py.  If you want to store other
kinds of commands too (though I don't know why because other commands
are not cumulative) you could use the "filename=" argument to the
Gnuplot constructor.

Michael

--
Michael Haggerty
hag...@jp...

Hi Chuck

> > Is there a way to plot Time/Data data in Gnuplot-py?
> > I've got some two dimensional data that looks like
> > the following:
> > 
> > 12:01:30    4.63
> > 12:02:30    6.74
> > 12:03:30    0.0
> > 12:04:30    6.32

[...]

> I don't have any experience myself with using date-formats in gnuplot,

Is there a date-format data type in Python ?. I browsed the docs
and couldn't find one. Or is there a class for that ?.

Anyway, it seems that the more straightforwars way to go would
be to write a small python function that converts a string "hh:mm:ss"
into a floating point. It should be doable in a few lines
of code.

A little fancier would be a date class, with conversion methods.
But may be that is overkill depending on what you need.

Hope this helps,
-- leo

Hello Micheal,

thanks for the quick answer and pointing me to the gnuplot-py-user list.
I somehow failed to notice there is one.

Michael Haggerty wrote:
> Lothar,
> 
> [I have cc'ed this email to the gnuplot-py-users mailing list.  Please
> subscribe to that list if you are interested in following Gnuplot.py
> developments:
> 
>     http://lists.sourceforge.net/lists/listinfo/gnuplot-py-users
> 
> .]
> 
> Lothar Birk <bi...@en...> writes:
> 
>>Dear Michael,
>>
>>first of all, thank your for your great tool which is very useful to
>>me creating plots on the fly for my lectures and papers.
>>
>>I recently had to move to an Win2k PC :-( and try to get some of my
>>Python scripts running there,
>>In all my scripts using Gnuplot I run into the following error message.
>>
>>Traceback (most recent call last):
>>   File "C:\Home\birk\src\pyprop\b-series\TESTBS~1.PY", line 46, in ?
>>     PDlist=[0.5,0.6,0.8,1.0,1.2,1.4])
>>   File "C:\Home\birk\src\pyprop\b-series\propseries.py", line 269, in 
>>plotKTKQ
>>     g.additem('set xrange [%f:%f]' % (Jmin,Jmax))
>>   File "C:\Home\birk\src\pyprop\b-series\IncrGnuplot.py", line 173, in 
>>additem
>>     self.__call__(plotitem)
>>   File "C:\program 
>>files\python22\Lib\site-packages\Gnuplot\_Gnuplot.py", line 206, in __call__
>>     self.gnuplot(s)
>>   File "C:\PROGRA~1\python22\lib\site-packages\Gnuplot\gp_win32.py", 
>>line 121, in __call__
>>     self.write(s + '\n')
>>IOError: [Errno 22] Invalid argument
>>
>>The weird thing is that it does not happen at the same place in the
>>script at different runs from a command terminal. May be this error
>>is not a Gnuplot.py issue at all, but related to system or python 
>>installation. I hope, however, you can provide me with hints where to look.
>>
>>I have python-2.2.1, gnuplot-py-1.6.1, Numeric-21.3 and a lot of
>>other stuff which runs as far as I know.
>>
>>Best regards
>>Lothar
> 
> 
> I don't think there's ever been a version 1.6.1 of Gnuplot.py
> released.  Are you using 1.6 or a more recent CVS version or ...?

OK it is the plain 1.6 distribution. I got confused by the numbering
of the rpms on sourceforge (1.6-1)

> 
> It looks like you are using a home-cooked extension to Gnuplot.py, so
> I could only guess what your problem might be.  Possibly the argument
> that you are passing to gnuplot.__call__ is not a sensible string as
> it should be.
> 
Yes it is a crooked extension, which maintains a list of all gnuplot
commands and allows you to build up a plot command by adding more and
more curves which finally get plotted into one diagrams.

However the error also occurs when I try to run the Gnuplot.py
demo:

C:\Program Files\python22\Lib\site-packages\Gnuplot>python demo.py
gnuplot> set title "A simple example"
gnuplot> set data style linespoints
gnuplot> plot 'C:\DOCUME~1\birk\LOCALS~1\Temp\~1200-0' notitle
Please press return to continue...

Traceback (most recent call last):
   File "demo.py", line 121, in ?
     demo()
   File "demo.py", line 47, in demo
     g.reset()
   File "C:\program 
files\python22\Lib\site-packages\Gnuplot\_Gnuplot.py", line 3
62, in reset
     self('reset')
   File "C:\program 
files\python22\Lib\site-packages\Gnuplot\_Gnuplot.py", line 2
06, in __call__
     self.gnuplot(s)
   File "C:\PROGRA~1\python22\lib\site-packages\Gnuplot\gp_win32.py", 
line 121, i
n __call__
     self.write(s + '\n')
IOError: [Errno 22] Invalid argument

> If you send us more information we might be able to help you.
> 
> Michael
> 
> --
> Michael Haggerty
> hag...@jp...
> 
Any help appreciated
Lothar
-- 
-- Lothar Birk -------------------------------------------------------
Visiting Professor, Dept. of Naval Architecture and Marine Engineering
University of Michigan
Phone +1 734 615 8061, Fax +1 734 936 8820, E-mail bi...@um...

Lothar,

[I have cc'ed this email to the gnuplot-py-users mailing list.  Please
subscribe to that list if you are interested in following Gnuplot.py
developments:

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.]

Lothar Birk <bi...@en...> writes:
> Dear Michael,
> 
> first of all, thank your for your great tool which is very useful to
> me creating plots on the fly for my lectures and papers.
> 
> I recently had to move to an Win2k PC :-( and try to get some of my
> Python scripts running there,
> In all my scripts using Gnuplot I run into the following error message.
> 
> Traceback (most recent call last):
>    File "C:\Home\birk\src\pyprop\b-series\TESTBS~1.PY", line 46, in ?
>      PDlist=[0.5,0.6,0.8,1.0,1.2,1.4])
>    File "C:\Home\birk\src\pyprop\b-series\propseries.py", line 269, in 
> plotKTKQ
>      g.additem('set xrange [%f:%f]' % (Jmin,Jmax))
>    File "C:\Home\birk\src\pyprop\b-series\IncrGnuplot.py", line 173, in 
> additem
>      self.__call__(plotitem)
>    File "C:\program 
> files\python22\Lib\site-packages\Gnuplot\_Gnuplot.py", line 206, in __call__
>      self.gnuplot(s)
>    File "C:\PROGRA~1\python22\lib\site-packages\Gnuplot\gp_win32.py", 
> line 121, in __call__
>      self.write(s + '\n')
> IOError: [Errno 22] Invalid argument
> 
> The weird thing is that it does not happen at the same place in the
> script at different runs from a command terminal. May be this error
> is not a Gnuplot.py issue at all, but related to system or python 
> installation. I hope, however, you can provide me with hints where to look.
> 
> I have python-2.2.1, gnuplot-py-1.6.1, Numeric-21.3 and a lot of
> other stuff which runs as far as I know.
> 
> Best regards
> Lothar

I don't think there's ever been a version 1.6.1 of Gnuplot.py
released.  Are you using 1.6 or a more recent CVS version or ...?

It looks like you are using a home-cooked extension to Gnuplot.py, so
I could only guess what your problem might be.  Possibly the argument
that you are passing to gnuplot.__call__ is not a sensible string as
it should be.

If you send us more information we might be able to help you.

Michael

--
Michael Haggerty
hag...@jp...

Chuck,

[I have cc'ed this email to the gnuplot-py-users mailing list.  Please
subscribe to that list if you are interested in following Gnuplot.py
developments:

    http://lists.sourceforge.net/lists/listinfo/gnuplot-py-users

.]

chuck clark <cn...@us...> writes:
> Michael,
> I am a decent Python programmer but just started
> using Gnuplot and Gnuplot-py yesterday so please
> forgive me if this is an obvious question with an
> obvious answer that I've just missed.
> Is there a way to plot Time/Data data in Gnuplot-py?
> I've got some two dimensional data that looks like
> the following:
> 
> 12:01:30    4.63
> 12:02:30    6.74
> 12:03:30    0.0
> 12:04:30    6.32
> 
> I can get this to plot directly in Gnuplot but I
> can't seem to create a Gnuplot.Data that can
> handle the time type data.  Is there something I'm
> missing?  If plotting this kind of data is not
> possible then is there any chance Gnuplot-py will
> be supporting it in the near future?

I don't have any experience myself with using date-formats in gnuplot,
so I wouldn't know how to support them in Gnuplot.py.  The Gnuplot.py
Data class stores its data internally as a Numeric array of floating
point data.  It has no way of storing (let alone plotting) data in
another format.  If gnuplot requires date data formatted as you
mentioned, how would you want to store it within Gnuplot.py?  As
strings?  Date objects of some sort?

If you have a rather specific purpose in mind, you could easily write
a class derived from PlotItem that prints its contents in the format
that you need.  If you want it to be more generally useful, you base
it on the Data class but instead of using Numeric arrays of float to
store its data it would use Python lists (or perhaps Numeric arrays of
Python objects, though last time I checked they didn't work too well).

If you decide to derive from PlotItem, then I would strongly recommend
that you base your work on the latest CVS version of Gnuplot.py since
the PlotItem interface has changed significantly.  I haven't gotten
around to making a new release but when I do it will include the new
interface.

In fact, I just realized that Numeric isn't really required for very
much in Gnuplot.py.  It might be easy to provide a non-Numeric mode,
which would be interesting to me at the moment because I'm mostly
using Jython in my current work and JNumeric isn't well-developed.

Yours,
Michael

--
Michael Haggerty
hag...@jp...