plot correctly up to asymptotes

[kcrisman]

Assuming this is a bug, not a feature:

sage: plot(1/x,0,1)
<boom>

My feeling is this should plot okay, since there is only one "bad"
point and the plotting code handles that kind of thing.

As far as I can tell from the traceback (relevant appended), the
problem is in the axes, which convert (at least when using
_tasteful_ticks) the endpoints to integers, given a big enough range.

sage: plot(1/x,0,1)
---------------------------------------------------------------------------
OverflowError                             Traceback (most recent call
last)

/Applications/sage/local/lib/python2.5/site-packages/sage/plot/plot.py
in _repr_(self)
    738         """
    739         if SHOW_DEFAULT:
--> 740             self.show()
    741             return ''
    742         else:

/Applications/sage/local/lib/python2.5/site-packages/sage/plot/plot.py
in show(self, xmin, xmax, ymin, ymax, figsize, filename, dpi, axes,
axes_labels, frame, fontsize, aspect_ratio)
   1252                   axes_labels=axes_labels,
   1253                   frame=frame, fontsize=fontsize,
-> 1254                   aspect_ratio=aspect_ratio)
   1255         os.system('%s %s 2>/dev/null 1>/dev/null &'%
(sage.misc.viewer.browser(), filename))
   1256

/Applications/sage/local/lib/python2.5/site-packages/sage/plot/plot.py
in save(self, filename, xmin, xmax, ymin, ymax, figsize, figure, sub,
savenow, dpi, axes, axes_labels, fontsize, frame, verify,
aspect_ratio)
   1429                 xmin,xmax,ymin,ymax = self._prepare_axes(xmin,
xmax, ymin, ymax)
   1430
-> 1431                 xmin, xmax, ymin, ymax =
sage_axes.add_xy_axes(subplot, xmin, xmax, ymin, ymax)
   1432
   1433                 subplot.set_xlim(xmin, xmax)

/Applications/sage/local/lib/python2.5/site-packages/sage/plot/axes.py
in add_xy_axes(self, subplot, xmin, xmax, ymin, ymax, axes, ticks,
axesstyle, axes_labels)
    324
    325         #evalute find_axes for y values and x ticks
--> 326         x_axis_ypos, ystep, ytslminor, ytslmajor =
self._find_axes(ymin, ymax)
    327         xltheight = 0.015*yspan
    328         xstheight = 0.25*xltheight

/Applications/sage/local/lib/python2.5/site-packages/sage/plot/axes.py
in _find_axes(self, minval, maxval)
    240             tslmajor, oppaxis, step =
self._tasteless_ticks(minval, maxval, 10)
    241         else:
--> 242             tslmajor, oppaxis, step =
self._tasteful_ticks(minval, maxval)
    243         min = tslmajor[0] - step
    244         tslminor = sage.misc.misc.srange(min, maxval +
0.2*step, 0.2*step)

/Applications/sage/local/lib/python2.5/site-packages/sage/plot/axes.py
in _tasteful_ticks(self, minval, maxval)
    124             else:
    125                 if maxval >= 10:
--> 126                     sl = [s for s in str(int(absmax))]
    127                     d0 = eval(sl[0])
    128                     d1 = eval(sl[1])

OverflowError: cannot convert float infinity to long

Component: graphics

Issue created by migration from https://trac.sagemath.org/ticket/3907

[mwhansen]

Attachment: trac_3907.patch.gz

[mwhansen]

comment:1

I've attached a patch which fixes the big traceback you get and actually produces a plot. This, however, does not fix the issue with the range on the y-axis being thrown of by asymptotes. I think that should be a separate ticket.

[sagetrac-mabshoff]

comment:2

Replying to @mwhansen:

I've attached a patch which fixes the big traceback you get and actually produces a plot. This, however, does not fix the issue with the range on the y-axis being thrown of by asymptotes. I think that should be a separate ticket.

kcrisman opened a ticket for that at #3985 - at least it seems very close to what you suggest.

Cheers,

Michael

[robertwb]

comment:3

Mostly looks good, but what about -inf?

[mwhansen]

comment:4

Attachment: trac_3907.2.patch.gz

I've updated the patch to handle the -inf case.

[rlmill]

comment:5

Apply only the second patch- applies cleanly to sage-3.1.2.alpha3 and passes tests in the files it touches.

[sagetrac-mabshoff]

comment:6

Merged in Sage 3.1.2.rc0