I still get an error:
p = contour_plot(f, (y, 0, 6), (t, 0, 3), fill = false,
axes_labels=['$gro$','$kro$'], contours = [0.1, 0.2, 0.3, 0.5, 0.7,
1.0, 2.0, 4.0], legend_label='qwall');
File "", line 1, in <module>
File "/tmp/tmpZLCoKg/___code___.py", line 6
return (sqrt(t**_sage_const_2 +y**_sage_const_2 )/(_sage_const_2
*pi*y))*(bessel_J(_sage_const_0 ,t).arccos()) if y != _sage_const_0
^
SyntaxError: invalid syntax
On Oct 17, 5:25 pm, "D. S. McNeil" <dsm...@gmail.com> wrote:
> > Sage: y,t = var('y,t')
> > Sage: contour_plot(lambda y,t: (sqrt(t^2+y^2)/(2*pi*y))*(bessel_J(0,
> > t ).arccos()), (t, 0, 3), (y, 0, 4), fill = false, axes_labels=['$gro
> > $','$kro$'], contours = [0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 2.0, 4.0],
> > fill=False, legend_label='qwall');
>
> > This is the error message that I get when processing the code:
>
> > The error I get is: File "<ipython console>", line 1 SyntaxError:
> > keyword argument repeated (<ipython console>, line 1).
>
> > Does it have something to do with assigning the variables?
>
> It has to do with the fact you're repeating a keyword argument. :^)
> Note that you write "fill=false" and then later "fill=False".
>
> Also, be careful: when you use a Python function (lambda or def), you
> can't use the (variable, lower, upper) syntax, you have to give them
> in order. Proof:
>
> sage: aa = []
> sage: bb = []
> sage: def f(a,b):
> ....: aa.append(a)
> ....: bb.append(b)
> ....: return a+b
> ....:
> sage: a,b = var("a b")
> sage: contour_plot(f,(b,2,3),(a,4,5))
>
> sage:
> sage: min(aa),max(aa)
> (2.0, 3.0)
> sage: min(bb),max(bb)
> (4.0, 5.0)
>
> And you see that f gets two variables ranging from 2 to 3 and 4 to 5,
> but it doesn't put the "a" values in a. (Aside for devs: we could fix
> this using introspection.)
>
> Finally, I found that I had to manually handle the zero case to avoid
> getting a "Symbolic division by zero" error:
>
> ----
> y,t = var('y,t')
>
> def f(y,t):
> return (sqrt(t^2+y^2)/(2*pi*y))*(bessel_J(0,t).arccos()) if y != 0
> else infinity
>
> p = contour_plot(f, (y, 0, 6), (t, 0, 3), fill = false,
> axes_labels=['$gro$','$kro$'], contours = [0.1, 0.2, 0.3, 0.5, 0.7,
> 1.0, 2.0, 4.0], legend_label='qwall');
> show(p)
> ----
>
> Hope some of that helps!
>
> Doug
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