More constexpr!

This MR focuses in FieldVector, FieldMatrix and iterator utilities. In particular, this is a step towards a constexpr reference elements in dune-geometry.

Note that this needs !1388 (closed) to be resolved.

added feature label

requested review from @simon.praetorius

assigned to @santiago.ospina

Have a look into !1401 . Let's do this transition to more constexpr step by step, I would suggest.

I am not convinced that re-implementing basic math stuff is the right approach. Rely on C++23 or even C++26 if you really need constexpr for exceptions and other difficult cases. With other words, guard the constexpr that do not compile with C++20 with feature macros or language macros.

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• 3996dc6c - Throw RangeError exception in bounds check instead of using DUNE_THROW

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added 69 commits

• 3996dc6c...fa579ea1 - 66 commits from branch master
• 1a16e388 - Add more constexpr qualifiers
• a15dbfd2 - More constexpr: backport constexpr versions of std::abs and std::sqrt
• cf1b6cb4 - Add integral and floating point constraints

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• 4885d6fa - Move back-port within macro
• 55370fb3 - Format document

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mentioned in merge request !1485 (merged)

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• 9e4c48ec - Format code

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• 0b36e315 - Use ADL to resolve std abs

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What is needed to make progress for this topic?

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• 0b36e315...8b31a737 - 34 commits from branch master
• 39bca8f4 - Add more constexpr qualifiers
• ad350c7b - More constexpr: backport constexpr versions of std::abs and std::sqrt
• a8e061dc - Add integral and floating point constraints
• 4f282d2a - Move back-port within macro
• f04e57fb - Format code
• a641a08b - Use ADL to resolve std abs
• ce8abde6 - Remove const-eval preprocessor check

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• 96212ee5 - Remove superfluous endif prerpocessor directive

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changed the description

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• 5987eea2 - Add more constexpr

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• f6843fb9 - Add more constexpr

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marked this merge request as ready

requested review from @gruenich and removed review request for @simon.praetorius

enabled an automatic merge when all merge checks for f6843fb9 pass

canceled the automatic merge

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• f6843fb9...8b31a737 - 14 commits from branch master
• 00256cb8 - Add more constexpr

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resolved all threads

enabled an automatic merge when all merge checks for 00256cb8 pass

merged

mentioned in commit 8f1177e4