Marks external neighbour set for recomputation

Also adds a variable to the main type to prevent DFTB+ updating the
neighbourlist if it has been set externally.

src/dftbp/dftbplus/initprogram.F90

@@ -266,6 +266,8 @@ module dftbp_dftbplus_initprogram
     !> Index in cellVec for each atom
     integer, allocatable :: iCellVec(:)
 
+    !> Are neighbour lists set externally (via the API), so should not be changed internally
+    logical :: areNeighSetExternal = .false.
 
     !> ADT for neighbour parameters
     type(TNeighbourList), allocatable :: neighbourList

src/dftbp/dftbplus/main.F90

@@ -1041,7 +1041,7 @@ subroutine processGeometry(this, env, iGeoStep, iLatGeoStep, tWriteRestart, tSto
           & this%img2CentCell, this%iCellVec, this%neighbourList, this%nAllAtom, this%coord0Fold,&
           & this%coord,this%species, this%rCellVec, this%nNeighbourSk, this%nNeighbourLC,&
           & this%ints, this%H0, this%rhoPrim, this%iRhoPrim, this%ERhoPrim, this%iSparseStart,&
-          & this%cm5Cont, errStatus)
+          & this%cm5Cont, this%areNeighSetExternal, errStatus)
         @:PROPAGATE_ERROR(errStatus)
     end if
 
@@ -2029,7 +2029,7 @@ subroutine handleCoordinateChange(env, boundaryCond, coord0, latVec, species0, c
       & tHelical, sccCalc, tblite, repulsive, dispersion, solvation, thirdOrd, rangeSep, reks,&
       & img2CentCell, iCellVec, neighbourList, nAllAtom, coord0Fold, coord, species, rCellVec,&
       & nNeighbourSK, nNeighbourLC, ints, H0, rhoPrim, iRhoPrim, ERhoPrim, iSparseStart, cm5Cont,&
-      & errStatus)
+      & areNeighSetExternal, errStatus)
 
     !> Environment settings
     type(TEnvironment), intent(in) :: env
@@ -2131,6 +2131,9 @@ subroutine handleCoordinateChange(env, boundaryCond, coord0, latVec, species0, c
     !> Charge model 5
     type(TChargeModel5), allocatable, intent(inout) :: cm5Cont
 
+    !> Are Neighbour lists set externally, so should not be updated
+    logical, intent(in) :: areNeighSetExternal
+
     !> Status of operation
     type(TStatus), intent(out) :: errStatus
 
@@ -2141,15 +2144,17 @@ subroutine handleCoordinateChange(env, boundaryCond, coord0, latVec, species0, c
     coord0Fold(:,:) = coord0
     call boundaryCond%foldCoordsToCell(coord0Fold, latVec)
 
-    if (tHelical) then
-      call updateNeighbourListAndSpecies(env, coord, species, img2CentCell, iCellVec,&
-          & neighbourList, nAllAtom, coord0Fold, species0, cutoff%mCutoff, rCellVec,&
-          & errStatus, helicalBoundConds=latVec)
-    else
-      call updateNeighbourListAndSpecies(env, coord, species, img2CentCell, iCellVec,&
-          & neighbourList, nAllAtom, coord0Fold, species0, cutoff%mCutOff, rCellVec, errStatus)
+    if (.not.areNeighSetExternal) then
+      if (tHelical) then
+        call updateNeighbourListAndSpecies(env, coord, species, img2CentCell, iCellVec,&
+            & neighbourList, nAllAtom, coord0Fold, species0, cutoff%mCutoff, rCellVec,&
+            & errStatus, helicalBoundConds=latVec)
+      else
+        call updateNeighbourListAndSpecies(env, coord, species, img2CentCell, iCellVec,&
+            & neighbourList, nAllAtom, coord0Fold, species0, cutoff%mCutOff, rCellVec, errStatus)
+      end if
+      @:PROPAGATE_ERROR(errStatus)
     end if
-    @:PROPAGATE_ERROR(errStatus)
 
     call getNrOfNeighboursForAll(nNeighbourSK, neighbourList, cutoff%skCutOff)
 

src/dftbp/dftbplus/mainapi.F90

@@ -138,6 +138,8 @@ subroutine setNeighbourList(env, main, nNeighbour, iNeighbour, neighDist, cutOff
     call setNeighbourListOrig(main%neighbourList, env, nNeighbour, iNeighbour, neighDist, cutOff,&
         & main%coord0, main%species0, coordNeighbours, neighbour2CentCell, main%rCellVec,&
         & main%nAllAtom, main%img2CentCell, main%iCellVec, main%coord, main%species)
+    main%areNeighSetExternal = .true.
+    main%tCoordsChanged = .true.
 
   end subroutine setNeighbourList
 

test/src/dftbp/api/mm/testers/test_neighbour_list.f90

@@ -41,12 +41,19 @@ program test_neighbour_list
   x = 2.5639291987021915_dp
   coord(:,:) = reshape([-x, -x, x, x, -x, -x, -x, x, -x, x, x, x], shape(coord))
   img2CentCell(:) = [2, 2, 2, 2]
-  nNeighbour(:) = [4, 0]
   iNeighbour(:,:) = reshape([1, 2, 3, 4, 0, 0, 0, 0], shape(iNeighbour))
   dist = sqrt(19.721198807872987_dp)
   neighDist(:,:) = reshape([dist, dist, dist, dist, 0.0_dp, 0.0_dp, 0.0_dp, 0.0_dp],&
       & shape(neighDist))
 
+  nNeighbour(:) = [3, 0]
+  ! set the neighbour list
+  call dftbp%setNeighbourList(nNeighbour, iNeighbour, neighDist, cutoff, coord, img2CentCell)
+  ! evaluate energy and forces
+  call dftbp%getEnergy(merminEnergy)
+  call dftbp%getGradients(gradients)
+
+  nNeighbour(:) = [4, 0]
   ! set the neighbour list
   call dftbp%setNeighbourList(nNeighbour, iNeighbour, neighDist, cutoff, coord, img2CentCell)