Bugs in Mathematica on Raspberry Pi 3?

[xxandra]

Replaying a sample of examples from the Wolfram Language & System Documentation Center on my newly acquired Raspberry Pi 3, I discovered the following:
The results of calculations on my Raspberry Pi are mostly the same as those shown in the Documentation Center. However, there are notable exceptions. For example, the plots of the functions of the NDEigensystem-code

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{vals, funs} =   NDEigensystem[{-Laplacian[u[x, y], {x, y}],     DirichletCondition[u[x, y] == 0, True]},    u[x, y], {x, y} \[Element] Disk[], 6];

are distinctively different from the plots of these functions in the Documentation Center. Which is in striking contrast to the plots of the comparable DEigensystem-code

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{vals, funs} =   DEigensystem[{-Laplacian[u[x, y], {x, y}],     DirichletCondition[u[x, y] == 0, True]},    u[x, y], {x, y} \[Element] Disk[], 6];

The DEigensystem-plots on my Raspberry are the same as in the Documentation Center. That is to say, under version 10.3.1. Under version 11.0.1.0, however, four of the plots show white blots on their 3D surfaces, as if there were discontinuities in the functions.

Further, plots of the Eigenfunctions in an L-shaped region produced from

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 L = Polygon[{{1, 0}, {2, 0}, {2, 2}, {0, 2}, {0, 1}, {1, 1}}]; {vals, funs} =   NDEigensystem[{Laplacian[u[x, y], {x, y}],     DirichletCondition[u[x, y] == 0., True]},    u[x, y], {x, y} \[Element] L, 6];

look like plots of minus the Eigenfunctions. Possibly as a consequence of the warning (shown on my Raspberry, but not in the Documentation Center) that "the second matrix (..) is not positive definite".

It should also be noted that plotting the NDEigensystem-functions takes less than 20 seconds under version 10.3.1, but about half an hour under version 11.0.1.0!

One wonders, how reliable is Mathematica's implementation on Raspberry Pi?

N.B. Results under Raspbian version d.d. 2016-11-25

[sibir]

I wrote some Mathematica code reading data fast from a TCP device. It works reliably under 10.3.1 but not version 11 or 12.

Any idea idea how to install version 10.3 now?

"sudo apt-get install wolfram-engine" installs version 12.0.1 and "apt-cache madison wolfram-engine" only shows that version as candidate

[ejolson]

I wrote some Mathematica code reading data fast from a TCP device. It works reliably under 10.3.1 but not version 11 or 12.

Any idea idea how to install version 10.3 now?

"sudo apt-get install wolfram-engine" installs version 12.0.1 and "apt-cache madison wolfram-engine" only shows that version as candidate

It might be a good idea to start a new thread related to your specific problem. Ideally version 12 should work as well.

[sibir]

I found a solution:

• create a fresh SD card with Jessie 2017-02-16 which last included Mathematica 10.3.1
• mark wolfram-engine to not be upgraded with

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  $ sudo apt-mark hold wolfram-engine

• the do the usual upgrades