Handle operations between surfaces of different topology

[HansKallekleiv]

Insert a description of your pull request (PR) here, and check off the boxes below when they are done.

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Contributor checklist

• 🎉 This PR closes Calculations between surfaces with different topology fails in SurfaceViewerFMU #665.
• 📜 I have broken down my PR into the following tasks:
  • Use xtgeo built in methods for operations between surfaces as they support different topologies
• 📖 I have considered adding a new entry in CHANGELOG.md, and added it if should be communicated there.

[jcrivenaes]

This should already be handled autmatically in xtgeo if you take operations between instances:
Let s1 and s2 be two RegularSurface() instances, then e.g.

diff = s1 - s2

shall regrid s2 to the topology of s1 behind the scene. See https://github.com/equinor/xtgeo/blob/ab3d188da03f100df65a62449473cccce5e43b5f/src/xtgeo/surface/_regsurf_oper.py#L44

[HansKallekleiv]

This should already be handled autmatically in xtgeo if you take operations between instances:
Let s1 and s2 be two RegularSurface() instances, then e.g.

diff = s1 - s2

shall regrid s2 to the topology of s1 behind the scene. See https://github.com/equinor/xtgeo/blob/ab3d188da03f100df65a62449473cccce5e43b5f/src/xtgeo/surface/_regsurf_oper.py#L44

Thanks @jcrivenaes . Changed code to do operations between instances.

[anders-kiaer]

👍