Re: [sage-support] 3d plotting in CoCalc with SageMath 8.0

2017-10-29 Thread William Stein 
For sage worksheets, I've created

 https://github.com/sagemathinc/cocalc/issues/2450

On Sun, Oct 29, 2017 at 1:12 PM William Stein  wrote:

> On Sun, Oct 29, 2017 at 9:31 AM Simon Willerton <
> s.willer...@sheffield.ac.uk> wrote:
>
>> I have the following code to help my students visualize surfaces
>>
>> t, theta = var('t, theta', domain='real')
>> x(t) = cosh(t)
>> z(t) = t
>> formula = (x(t)*cos(theta), x(t)*sin(theta), z(t))
>> parameters = ((t, -3, 3), (theta, -pi, pi))
>> surface = ParametrizedSurface3D(formula, parameters)
>> show(surface.plot(aspect_ratio=1, color='yellow'), viewer='threejs')
>>
>> This works fine in SageMathCell (running SageMath 8.0) see
>>
>> http://simonwillerton.staff.shef.ac.uk/teaching/MAS336/sage_cell_surfaces.html
>> The reason I'm using threejs is so that many plots can been seen on a
>> single page.  Without it (using jmol, I think) this wasn't possible.
>>
>> The code also works fine in a jupyter notebook running SageMath 8.0 on OS
>> X in both firefox and chrome.
>>
>> However the code does not run in SageMath 8.0 on CoCalc.  In a sagews it
>> actually gives an error,
>>
>
> It works fine in CoCalc (and uses threejs) if you do not give the viewer=
> option.
>
> and in Jupyter (on firefox or chrome) the image just never appears.
>> Changing the kernel to 7.6 on Jupyter on CoCalc allows the image to appear
>> correctly.
>>
>> Should I not be using threejs or is the problem with CoCalc?
>>
>> Cheers,
>>
>> Simon
>>
>>
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> --
> -- William Stein
>
-- 
-- William Stein

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Re: [sage-support] 3d plotting in CoCalc with SageMath 8.0

2017-10-29 Thread William Stein 
On Sun, Oct 29, 2017 at 9:31 AM Simon Willerton 
wrote:

> I have the following code to help my students visualize surfaces
>
> t, theta = var('t, theta', domain='real')
> x(t) = cosh(t)
> z(t) = t
> formula = (x(t)*cos(theta), x(t)*sin(theta), z(t))
> parameters = ((t, -3, 3), (theta, -pi, pi))
> surface = ParametrizedSurface3D(formula, parameters)
> show(surface.plot(aspect_ratio=1, color='yellow'), viewer='threejs')
>
> This works fine in SageMathCell (running SageMath 8.0) see
>
> http://simonwillerton.staff.shef.ac.uk/teaching/MAS336/sage_cell_surfaces.html
> The reason I'm using threejs is so that many plots can been seen on a
> single page.  Without it (using jmol, I think) this wasn't possible.
>
> The code also works fine in a jupyter notebook running SageMath 8.0 on OS
> X in both firefox and chrome.
>
> However the code does not run in SageMath 8.0 on CoCalc.  In a sagews it
> actually gives an error,
>

It works fine in CoCalc (and uses threejs) if you do not give the viewer=
option.

and in Jupyter (on firefox or chrome) the image just never appears.
> Changing the kernel to 7.6 on Jupyter on CoCalc allows the image to appear
> correctly.
>
> Should I not be using threejs or is the problem with CoCalc?
>
> Cheers,
>
> Simon
>
>
> --
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> For more options, visit https://groups.google.com/d/optout.
>
-- 
-- William Stein

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[sage-support] Re: 3d plotting in CoCalc with SageMath 8.0

2017-10-29 Thread Eric Gourgoulhon 
Hi, 

You must add the keyword argument online=True to show(...):

show(surface.plot(aspect_ratio=1, color='yellow'), viewer='threejs', online=
True)

Then it works in a Jupyter notebook running SageMath 8.0 in CoCalc:
https://cocalc.com/projects/551a1e1d-9360-47bf-89ba-91603e96c7fe/files/2017-10-29-20.ipynb

More generally online=True (which was introduced in SageMath 8.0) is 
necessary to share threejs plots on the web, e.g. via nbviewer.jupyter.org.

Eric.


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[sage-support] 3d plotting in CoCalc with SageMath 8.0

2017-10-29 Thread Simon Willerton 
I have the following code to help my students visualize surfaces

t, theta = var('t, theta', domain='real')
x(t) = cosh(t)
z(t) = t
formula = (x(t)*cos(theta), x(t)*sin(theta), z(t))
parameters = ((t, -3, 3), (theta, -pi, pi))
surface = ParametrizedSurface3D(formula, parameters)
show(surface.plot(aspect_ratio=1, color='yellow'), viewer='threejs')

This works fine in SageMathCell (running SageMath 8.0) see
  
http://simonwillerton.staff.shef.ac.uk/teaching/MAS336/sage_cell_surfaces.html
The reason I'm using threejs is so that many plots can been seen on a 
single page.  Without it (using jmol, I think) this wasn't possible.

The code also works fine in a jupyter notebook running SageMath 8.0 on OS X 
in both firefox and chrome.

However the code does not run in SageMath 8.0 on CoCalc.  In a sagews it 
actually gives an error, and in Jupyter (on firefox or chrome) the image 
just never appears.  Changing the kernel to 7.6 on Jupyter on CoCalc allows 
the image to appear correctly.

Should I not be using threejs or is the problem with CoCalc?

Cheers,

Simon


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[sage-support] Re: [piecewise] AttributeError: ComplexField_class_with_category object has no attribute complex_field

2017-10-29 Thread Marcel Partap 
like basically, why don't the piecewise functions collapse to scalars? This 
should result in the same output, no?
M_vec(x) = vector([M_Tx(x), M_by(x), M_bz(x)]).column()
M_vec(x = l1)
M_vec_l1 = vector([M_Tx(l1), M_by(x=l1), M_bz(x=l1)]).column()
M_vec_l1

gives instead
[piecewise(x|-->238.7324 on 
[0, 200], x|-->0 on (200, 450); x)]
[ piecewise(x|-->-4.270333*x on [0, 200], x|-->3.416267*x - 
1537.320 on (200, 450); x)]
[piecewise(x|-->-0.9833111*x on [0, 200], x|-->1.076289*x - 
484.3300 on (200, 450); x)]
[ 238.7324]
[-854.0667]
[-196.6622]


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[sage-support] [piecewise] AttributeError: ComplexField_class_with_category object has no attribute complex_field

2017-10-29 Thread Marcel Partap 
For graphing strain load on a shaft in relation to coordinate x, I have 
created a set of piecewise functions. Now I wanted to munge them into a 
single parametrized vector to easily get the length via norm() at a 
specified point.

M_Tx = piecewise([[[0, l1], M_t], [(l1, l1+l2), 0]])
M_by = piecewise([[[0, l1], -A_z * x], [(l1, l1+l2), -B_z * (l1+l2-x)]])
M_bz = piecewise([[[0, l1], A_y * x], [(l1, l1+l2), B_y * (l1+l2-x)]])
N_x = piecewise([[[0, l1], -A_x], [(l1, l1+l2), 0]])
Q_y = piecewise([[[0, l1], -A_y], [(l1, l1+l2), B_y]])
Q_z = piecewise([[[0, l1], -A_z], [(l1, l1+l2), B_z]])


M_vec(x) = vector([M_Tx, M_by, M_bz]).column()
show(r"$\vec M=\left(\begin{array}{c} M_{Tx} \\ M_{by} \\ M_{bz} 
\end{array}\right)=$", M_vec(x = l1).n(digits=4), "kN $=$", round(M_vec(x = 
l1).norm(), 4), "kN")



But, this does not work.

Error in lines 27-27
Traceback (most recent call last):
  File "/cocalc/lib/python2.7/site-packages/smc_sagews/sage_server.py", 
line 996, in execute
exec compile(block+'\n', '', 'single') in namespace, locals
  File "", line 1, in 
  File "sage/structure/element.pyx", line 838, in sage.structure.element.
Element.n (/ext/sage/sage-8.0/src/build/cythonized/sage/structure/element.c:
7961)
return self.numerical_approx(prec, digits, algorithm)
  File "sage/symbolic/expression.pyx", line 5718, in sage.symbolic.
expression.Expression.numerical_approx (/ext/sage/sage-8.0/src/build/
cythonized/sage/symbolic/expression.cpp:35056)
x = x._convert(kwds)
  File "sage/symbolic/expression.pyx", line 1261, in sage.symbolic.
expression.Expression._convert (/ext/sage/sage-8.0/src/build/cythonized/sage
/symbolic/expression.cpp:10465)
cdef GEx res = self._gobj.evalf(0, kwds)
  File "sage/libs/pynac/pynac.pyx", line 1343, in 
sage.libs.pynac.pynac.py_float 
(/ext/sage/sage-8.0/src/build/cythonized/sage/libs/pynac/pynac.cpp:15280)
return p.complex_field()(n)
  File "sage/structure/category_object.pyx", line 823, in sage.structure.
category_object.CategoryObject.__getattr__ (/ext/sage/sage-8.0/src/build/
cythonized/sage/structure/category_object.c:7662)
return self.getattr_from_category(name)
  File "sage/structure/category_object.pyx", line 838, in sage.structure.
category_object.CategoryObject.getattr_from_category (/ext/sage/sage-8.0/src
/build/cythonized/sage/structure/category_object.c:7826)
attr = getattr_from_other_class(self, cls, name)
  File "sage/structure/misc.pyx", line 294, in 
sage.structure.misc.getattr_from_other_class 
(/ext/sage/sage-8.0/src/build/cythonized/sage/structure/misc.c:1866)
raise dummy_attribute_error
AttributeError: 'ComplexField_class_with_category' object has no attribute 
'complex_field'


Is it that piecewise functions are not yet fully fledged out, or is my lack 
of sage routine that is to blame?
Any hints most welcome : )

#Best Regards/Marcel

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