problems with the docs

I am brand new to ngsolve but installed it today and and keen to learn to use it. There are a couple of problems that I found in the docs and I am not sure if it is well known or not.

First, in installing ngsolve on jupyter on my ubuntu system, I needed to install jupyter-notebook as well, and the install command did not work but needed to use enable, as copied below.

sudo apt install jupyter-notebook
jupyter nbextension enable ngsolve --user --py

Second, I found about 6 or so examples in the notebooks that did not run, the first of which was the notebook on Maxwells equations. I can provide a longer list if need be.

I presume these are known but wanted to try and contribute in case they aren't.

Hi Poulin,

welcome to NGSolve. Yes, please tell us what is not working.

You may also watch the tutorials on youtube to see how they should work, e.g. the Maxwell tutorial:



Joachim

Hello Joachim,

Thanks for sharing this video wtih me.

I understand the setup of the code but the problem I had was with an error.

In particular, I am copying the error message below. I will copy other errors that I get in the other codes in separate lines.

---

AttributeError Traceback (most recent call last)
<ipython-input-5-47895662d752> in <module>
5 from math import pi
6 mu0 = 4*pi*1e-7
----> 7 mur = mesh.MaterialCF({"magnet" : 1000}, default=1)
8
9 a = BilinearForm(fes)

AttributeError: 'ngsolve.comp.Mesh' object has no attribute 'MaterialCF'

2.6 Stokes Equation

TypeError Traceback (most recent call last)
<ipython-input-2-4cfe5b119a48> in <module>
1 V = H1(mesh, order=2, dirichlet="wall|inlet|cyl")
2 Q = H1(mesh, order=1)
----> 3 X = V*V*Q

TypeError: unsupported operand type(s) for *: 'ngsolve.comp.H1' and 'ngsolve.comp.H1'

2.11 Matrix free operator application¶

---

NameError Traceback (most recent call last)
<ipython-input-4-8901926dddb7> in <module>
2 felS = Sigma.GetFE(el)
3 felV = V.GetFE(el)
----> 4 fel = MixedFE(felS, felV)
5 trafo = mesh.GetTrafo(el)
6

NameError: name 'MixedFE' is not defined

3.3 Discontinuous Galerkin Discretizations for linear transport

---

TypeError Traceback (most recent call last)
<ipython-input-11-05fb163505bf> in <module>
1 # this does not work:
2 c2 = BilinearForm(VT)
----> 3 res.data = c2.mat * gfu.vec

TypeError: matrix not ready - assemble bilinearform first