On Dec 10, 2007 8:29 PM, Jonathan Bober <[EMAIL PROTECTED]> wrote:
>
> Hi all. I just opened ticket #1457 (see below)
>
> http://trac.sagemath.org/sage_trac/ticket/1457
>
> The following is hopefully pretty self explanatory:
>
> -----------------------------------
>
> The following took place on an Intel Core Duo (32 bit) running Ubuntu
> 7.10. Hopefully the cause is obvious for someone familiar with the
> calculus/plotting code.
>
> (Note: replacing f(x) with f(x) = 2.0 * sqrt(x^2.0 + 300.0^2.0) - x +
> 1000.0 is a suitable workaround.)
>
>
> ----------------------------------------------------------------------
> | SAGE Version 2.8.15, Release Date: 2007-12-03 |
> | Type notebook() for the GUI, and license() for information. |
> ----------------------------------------------------------------------
>
> sage: f(x) = 2 * sqrt(x^2 + 300^2) - x + 1000
> sage: P = f.diff(x).diff(x).plot(xmin=0,xmax=1000)
> ---------------------------------------------------------------------------
> <type 'exceptions.AssertionError'> Traceback (most recent call last)
>
Note
sage: x = var("x")
sage: f = lambda x: 2 * sqrt(x^2 + 300^2) - x + 1000
sage: P = f(x).diff(x).diff(x).plot(xmin=0,xmax=1000)
sage: show(P)
sage: g = 2 * sqrt(x^2 + 300^2) - x + 1000
sage: P = g.diff(x).diff(x).plot(xmin=0,xmax=1000)
sage: show(P)
both work and yield the same plot.
> /home/bober/sage-2.8.15.alpha1/<ipython console> in <module>()
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/calculus/calculus.py
> in plot(self, *args, **kwds)
> 602 else:
> 603 f = self.function(param)
> --> 604 return plot(f, *args, **kwds)
> 605
> 606 def __lt__(self, right):
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/plot/plot.py
> in __call__(self, funcs, *args, **kwds)
> 2303 G = funcs.plot(*args, **kwds)
> 2304 else:
> -> 2305 G = self._call(funcs, *args, **kwds)
> 2306 if do_show:
> 2307 G.show()
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/plot/plot.py
> in _call(self, funcs, xmin, xmax, parametric, polar, label, show, **kwds)
> 2353
> 2354 try:
> -> 2355 y = f(x)
> 2356 data.append((x, float(y)))
> 2357 except (ZeroDivisionError, TypeError, ValueError), msg:
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/calculus/calculus.py
> in <lambda>(x)
> 591 else:
> 592 param = A[0]
> --> 593 f = lambda x: self(x)
> 594 else:
> 595 A = self.variables()
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/calculus/calculus.py
> in __call__(self, *args)
> 4012 vars = self.args()
> 4013 dct = dict( (vars[i], args[i]) for i in range(len(args)) )
> -> 4014 return self._expr.substitute(dct)
> 4015
> 4016 def _repr_(self, simplify=True):
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/calculus/calculus.py
> in substitute(self, in_dict, **kwds)
> 2589 kwds = self.__parse_in_dict(in_dict, kwds)
> 2590 kwds = self.__varify_kwds(kwds)
> -> 2591 return X._recursive_sub(kwds)
> 2592
> 2593 def subs(self, *args, **kwds):
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/calculus/calculus.py
> in _recursive_sub(self, kwds)
> 3424 """
> 3425 ops = self._operands
> -> 3426 new_ops = [SR(op._recursive_sub(kwds)) for op in ops]
> 3427
> 3428 #Check to see if all of the new_ops are symbolic constants
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/calculus/calculus.py
> in _recursive_sub(self, kwds)
> 3424 """
> 3425 ops = self._operands
> -> 3426 new_ops = [SR(op._recursive_sub(kwds)) for op in ops]
> 3427
> 3428 #Check to see if all of the new_ops are symbolic constants
>
> /home/bober/sage-2.8.15.alpha1/local/lib/python2.5/site-packages/sage/calculus/calculus.py
> in _recursive_sub(self, kwds)
> 3430 is_constant = all(map(lambda x: isinstance(x,
> SymbolicConstant), new_ops))
> 3431 if is_constant:
> -> 3432 return SymbolicConstant( self._operator(*map(lambda x:
> x._obj, new_ops)) )
> 3433 else:
> 3434 return self._operator(*new_ops)
>
> /home/bober/sage-2.8.15.alpha1/rational.pyx in
> sage.rings.rational.Rational.__pow__()
>
> <type 'exceptions.AssertionError'>: BUG: Rational.__pow__ called on a
> non-Rational
> sage:
>
>
>
> >
>
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