[Pw_forum] Intermediate images in NEB

[Daniele Passerone]

Dear forum members

We noticed a small bug in the neb capabilities of pwscf, or maybe we
are missing something.
Indeed, the program seems to set always a linear interpolation between
first a last image, even when the
intermediate images are given.

The origin seems to be in the subroutine initial_guess (module
path_base.f90)
where an array pos_n with the linearly interpolated position is built.

The purpose should be to copy pos_n(:,:) in the pos(:,:) vector only if
the intermediate images given by the user are absent or 
unreasonable.
Unfortunately,
there is a line

pos(:,:) = pos_n(:,:)

that always copies the linear guess into the position array.

For the moment i modified this line into 

        if (input_images .ne. num_of_images) then
             pos(:,:) = pos_n(:,:)
         endif

And that should do the job.


Best regards,

Daniele Passerone