DFT+U stress tensor

Description

Implements the contribution from LDA+U stress tensor to the stress tensor.

Closes #678 (closed)

News snippet

Implements the contribution from LDA+U stress tensor to the stress tensor.

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.

changed milestone to %15.0

added Feature label

assigned to @nicolastd

marked this merge request as draft

added 1 commit

• 8fea719c - Implements the contribution from LDA+U stress tensor to the stress tensor.

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added 1 commit

• 5075c0d8 - Implements the contribution from LDA+U stress tensor to the stress tensor.

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marked this merge request as ready

@AlexBuccheri If you find some time for reviewing, here comes the DFT+U contribution to the stress tensor. Apart from mGGAs and EXX, almost everything is implemented now

@AlexBuccheri Just pinging you again on this one, if you have time.