On Jan 1, 2008 6:16 PM, lwd <[EMAIL PROTECTED]> wrote:
>
> First of all "A Happy New Year to everyone!"
> Ok, sage-2.9.1-linux-ubuntu-32bit-i686-Linux on Ubuntu 7.10 machine I
> get a plot for this:
> sage: maxima.plot2d('[-7.5/-0.5*(x-0.5)+8,-7.5/7.5*(x-0.5)+8]','[x,
> 0,8]', '[y, 0, 8],[ylabel,"y"],[gnuplot_preamble, "set grid xtics
> ytics"],[legend,false]')
>
> But not for this ugliness:
>
> sage: maxima.plot2d('[-7.5/-0.5*(x-0.5)+8, -7.5/7.5*(x-0.5)+8,
> -6.5/-0.5*(x-0.5)+8, -6.5/7.5*(x-0.5)+8, -5.5/-0.5*(x-0.5)+8,
> -5.5/7.5*(x-0.5)+8, -4.5/-0.5*(x-0.5)+8, -4.5/7.5*(x-0.5)+8,
> -3.5/-0.5*(x-0.5)+8, -3.5/7.5*(x-0.5)+8, -2.5/-0.5*(x-0.5)+8,
> -2.5/7.5*(x-0.5)+8, -1.5/-0.5*(x-0.5)+8, -1.5/7.5*(x-0.5)+8,
> -0.5/-0.5*(x-0.5)+8, -0.5/7.5*(x-0.5)+8]','[x,0,8]', '[y, 0, 8],
> [ylabel,"y"], [gnuplot_preamble, "set grid xtics ytics"],
> [legend,false]')
>
> or this
> sage: maxima('plot2d([-7.5/-0.5*(x-0.5)+8, -7.5/7.5*(x-0.5)+8,
> -6.5/-0.5*(x-0.5)+8, -6.5/7.5*(x-0.5)+8, -5.5/-0.5*(x-0.5)+8,
> -5.5/7.5*(x-0.5)+8, -4.5/-0.5*(x-0.5)+8, -4.5/7.5*(x-0.5)+8,
> -3.5/-0.5*(x-0.5)+8, -3.5/7.5*(x-0.5)+8, -2.5/-0.5*(x-0.5)+8,
> -2.5/7.5*(x-0.5)+8, -1.5/-0.5*(x-0.5)+8, -1.5/7.5*(x-0.5)+8,
> -0.5/-0.5*(x-0.5)+8, -0.5/7.5*(x-0.5)+8]','[x,0,8]', '[y, 0, 8],
> [ylabel,"y"], [gnuplot_preamble, "set grid xtics ytics"],
> [legend,false])')
It would be better to try
sage: maxima.eval(...)
above.
>
> which returns:
> sage0
>
> but no plot.
> But in maxima plot2d(...) works, also in maxima.console()
> Octave is different; it pops a gnuplot window with some lines and
> raise the following error:
> sage: octave('fplot("[-7.5/-0.5*(x-0.5)+8, -7.5/7.5*(x-0.5)+8,
> -6.5/-0.5*(x-0.5)+8, -6.5/7.5*(x-0.5)+8, -5.5/-0.5*(x-0.5)+8,
> -5.5/7.5*(x-0.5)+8, -4.5/-0.5*(x-0.5)+8, -4.5/7.5*(x-0.5)+8,
> -3.5/-0.5*(x-0.5)+8, -3.5/7.5*(x-0.5)+8, -2.5/-0.5*(x-0.5)+8,
> -2.5/7.5*(x-0.5)+8, -1.5/-0.5*(x-0.5)+8, -1.5/7.5*(x-0.5)+8,
> -0.5/-0.5*(x-0.5)+8, -0.5/7.5*(x-0.5)+8]",[0,8])')
> ---------------------------------------------------------------------------
> <type 'exceptions.TypeError'> Traceback (most recent call
> last)
>
> /home/lwdrob/Disertatie/<ipython console> in <module>()
>
> /usr/local/sage/local/lib/python2.5/site-packages/sage/interfaces/
> expect.py in __call__(self, x)
> 736 return x
> 737 if isinstance(x, basestring):
> --> 738 return cls(self, x)
> 739 try:
> 740 return self._coerce_from_special_method(x)
>
> /usr/local/sage/local/lib/python2.5/site-packages/sage/interfaces/
> expect.py in __init__(self, parent, value, is_name)
> 987 except (TypeError, KeyboardInterrupt,
> RuntimeError, ValueError), x:
> 988 self._session_number = -1
> --> 989 raise TypeError, x
> 990 self._session_number = parent._session_number
> 991
>
> <type 'exceptions.TypeError'>: Error executing code in Octave
> CODE:
>
> sage4=fplot("[-7.5/-0.5*(x-0.5)+8,-7.5/7.5*(x-0.5)+8,-6.5/-0.5*(x-0.5)+8,-6.5/7.5*(x-0.5)+8,-5.5/-0.5*(x-0.5)+8,-5.5/7.5*(x-0.5)+8,-4.5/-0.5*(x-0.5)+8,-4.5/7.5*(x-0.5)+8,-3.5/-0.5*(x-0.5)+8,-3.5/7.5*(x-0.5)+8,-2.5/-0.5*(x-0.5)+8,-2.5/7.5*(x-0.5)+8,-1.5/-0.5*(x-0.5)+8,-1.5/7.5*(x-0.5)+8,-0.5/-0.5*(x-0.5)+8,-0.5/7.5*(x-0.5)+8]",
> [0,8]);
> Octave ERROR:
> error: value on right hand side of assignment is undefined
> error: evaluating assignment expression near line 1, column 6
> error: near line 1 of file `/home/lwdrob/.sage//temp/lwdrob_comp/7546//
> interface//tmp'
> error: source: error sourcing file `/home/lwdrob/.sage//temp/
> lwdrob_comp/7546//interface//tmp'
>
> But in octave and octave.console() in works.
Do
sage: octave.eval(...)
that is equivalent to just typing in the contents of eval to octave. Doing
sage: foo = octave(...)
is different -- it makes a Python object that wraps an octave object -- this
makes no sense if ... doesn't evaluate to an octave object.
> Any ideas are welcomed.
In that case, here's a quick remark. You can easily just draw the above plots
in Sage directly, without using any of gnuplot/maxima/octave at all:
show(plot([-7.5/-0.5*(x-0.5)+8, -7.5/7.5*(x-0.5)+8, \
-6.5/-0.5*(x-0.5)+8, -6.5/7.5*(x-0.5)+8, -5.5/-0.5*(x-0.5)+8, \
-5.5/7.5*(x-0.5)+8, -4.5/-0.5*(x-0.5)+8, -4.5/7.5*(x-0.5)+8, \
-3.5/-0.5*(x-0.5)+8, -3.5/7.5*(x-0.5)+8, -2.5/-0.5*(x-0.5)+8, \
-2.5/7.5*(x-0.5)+8, -1.5/-0.5*(x-0.5)+8, -1.5/7.5*(x-0.5)+8, \
-0.5/-0.5*(x-0.5)+8, -0.5/7.5*(x-0.5)+8], 0, 8), ymin=0,ymax=8)
Sage has extremely good 2d graphics built in, which are built
on matplotlib:
http://matplotlib.sourceforge.net/
See
http://sagemath.org/doc/html/ref/module-sage.plot.plot.html
for how to use it from Sage. Our goal is that this, plus our new
interactive 3d graphics (coming soon), will be substantially better
than gnuplot (which is what both Maxima and Octave rely on
for the above commands). If nothing else, the *license* is much
better than the gnuplot license, which is not GPL-compatible.
This is why Sage cannot include gnuplot, and programs
such as Octave and Maxima can't (legally) binary link with
gnuplot. If you check the Octave devel mailing list, you'll see
one of the main pushes in Octave development right now is
a new graphics engine so that can get away from gnuplot.
-- William
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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