Driver generation for examples with matrix-free preconditioners

Make it possible to generate the driver and driverblock for examples using matrix-free preconditioners.

In order to build the matrix-free solvers in your solver block you need to:

1. Specify all necessary operators in the ini file, see eg dune-codegen/test/matrix-free-preconditioner/ for an example.
2. You need to set the two form options matrix-free-preconditioner and matrix_free_preconditioner_operators in your main form.
3. You need to set the driver_blocks option and within the driver block set the correct spatial_form.

After setting all these dune-codegen will generate all the operators, create a driverblock using them and generate the correct driver code.

Note: One change I did to the driver generation: If there is exactly one driver block we can always generate a driver, no matter how many operators are defined, as it is always clear that the driver should use the solver from the driver block.

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• b74a5ff7...266a0eac - 17 commits from branch master
• 19d9fd9c - [skipci][WIP] Driver implementation of matrix free solvers
• 956a943e - [skipci][WIP] Driverblock generation with proper file- and classnames
• 9f7a40ad - Fix bug in matrix-free preconditioner generation
• f83e45e0 - Generate driver if only one driverblock exists
• 9ae68f0a - Generate driver in test case

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• d03d1f80 - Remove preconditioner folder

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• 28749f54 - Fix flake8

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• 5fdb6030 - Fix flake8

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marked this merge request as ready

changed the description

@dominic It was good that we talked about it on Friday. It was very easy to implement it this way as the whole driver block business was more flexible than I thought.

One note: So far this is still a bit lacking as I cant generate two driver blocks, one matrix-based and one matrix-free, from the same operators. So far the choice of matrix-free solver in the driver block is deduced from the matrix-free option in the form. I will change this in a follow up MR.

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• 862f2106 - Fix dependency in test

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mentioned in merge request !428 (merged)

@marcel.koch Do you have opinions regarding this? Here the changes to the driver generation itself are quite small so I would hope that it doesn't interfere with your MRs.

mentioned in merge request !422 (merged)

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• 862f2106...cab23943 - 55 commits from branch master
• 6139d179 - Merge branch 'master' into feature/matrix-free-driver-generation

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resolved all threads

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• 43922db8 - Untabify: Meld introduced tabs...

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I updated this to the current master and will merge tomorrow. Changes should be uncontroversial.

merged

mentioned in commit 66783bbe