Improve mesh batch nrm2: add OpenMP parallelization for packed batches

Description

Add OpenMP parallelization for the norm calculation (mesh_batch_nrm2).

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.

added Optimization label

Codecov Report

Merging #882 into develop will decrease coverage by 0.00%. The diff coverage is 63.88%.

@@             Coverage Diff             @@
##           develop     #882      +/-   ##
===========================================
- Coverage    70.76%   70.76%   -0.01%     
===========================================
  Files          501      501              
  Lines        96456    96472      +16     
===========================================
+ Hits         68258    68268      +10     
- Misses       28198    28204       +6     

Impacted Files	Coverage Δ
src/grid/mesh_batch.F90	100.00% <ø> (ø)
src/grid/mesh_batch_inc.F90	88.44% <63.88%> (-0.75%)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update e0511a4...6072f27. Read the comment docs.

added 25 commits

• b737afdf...e0511a41 - 23 commits from branch develop
• e066665d - Improve nrm2: less calls to abs
• 5dc40ba3 - OpenMP version of mesh_batch_nrm2 for packed states

Compare with previous version

added 1 commit

• e03fac84 - OpenMP version of mesh_batch_nrm2 for packed states

Compare with previous version

assigned to @nicolastd

added 2 commits

• ad4a8004 - Remove unnecessary multiplication by 1
• 9ee8145f - Split sum in real and imaginary part in nrm2

Compare with previous version

resolved all threads

approved this merge request

added 1 commit

• 6072f272 - Fix logic of checking if component in sum is non-zero

Compare with previous version

@nicolastd the pipeline now passes with the most recent fix.

approved this merge request

merged

mentioned in commit 0f2a5bad

mentioned in issue #328 (closed)

changed milestone to %10.0

added in Changelog label