Is cbc app supported?

Site Feedback
1

Dear all,

I have tried to use the latest version of the cbc app with the stable release of Fenics (2019.1.0) . Unfortunately I cannot get the biot.py demo to run. I get the error :
RuntimeError: Can’t allocate vector - no usable template for block 0.
Consider calling something like bb.allocate([V, Q]) to initialise the block_vec.

Is the cbc app still supported by any project or shall we try to find an alternative within Fenics?

Thanks,
Nicolas

2

Hi,

No further information on the cbc app?

Nicolas

3

I guess the cbc app you are talking about is cbc.block.
I am not sure cbc.block is fully compatible with python 3 and/or the last FEniCS.

As far as I can tell : I can reproduce the error you get using Python 3 and the last FEniCS (2019.1.0), but I don’t get that error if I use Python 2 and FEniCS 2017.2.0 (which is the last version supporting Python 2).

4

Thank you very much for your answer Cécile.
I will give FEniCS 2017.2.0 a try in order to use cbc.block.
BTW, do you know if there exist an alternative to this module in the latest version of FEnICS?

5

Maybe take a look at @francesco-ballarin’s library multiphenics:

I haven’t used it much myself, although it appears to have some support for block linear algebra. See, e.g., the Stokes inf-sup tutorial.