Difference between IDPP interpolation for NEB in 23.12 version and 22.12 version

[pshinyeong]

Hello,

Previously in 2022.12 version when I generate NEB configuration with Image Dependent Pair Potential interpolation, the python script would set generate_images parameter as false.

e.g
NudgedElasticBand(generate_images=False)

However in 2023.12 version, generating NEB configuration with IDPP sets generate_images parameter as ImageDependentPairPotential

e.g
NudgedElasticBand(generate_images=ImageDependentPairPotential())

Does this mean that in the 2022.12 version, image dependent pair potential was not implemented when generating NEB configurations even though I set the interpolation as IDPP (in the QATK interface, not the python script)?

[Anders Blom]

No, your images were still correctly interpolated with IDPP in the old version too. It's just that in the new version we provide more options to re-interpolate the path, and it is then convenient to script the keywords needed, as a template.

Now, there is a small practical consequence to doing that, because actually it will always do a re-interpolation if the keyword generate_images is not False, and moreover it does a small random perturbation when doing that. So actually, in the new version, the initial path you will be running with is slightly different from the one in the script. The perturbation is however not random if you run multiple times, as the random seed is fixed. We might improve this in future versions, to make the re-interpolation more explicit on-demand.