Initial working commit with bug in delete command

src/subroutines.f90

@@ -289,4 +289,63 @@ module subroutines
         end do
     end subroutine
 
+    subroutine build_cell_list(numinlist, r_list, rc_off, cell_num, num_in_cell, cell_list, which_cell)
+        !This subroutine builds a cell list based on rc_off
+        
+        !----------------------------------------Input/output variables-------------------------------------------
+
+        integer, intent(in) :: numinlist !The number of points within r_list
+
+        real(kind=dp), dimension(3,numinlist), intent(in) :: r_list !List of points to be used for the construction of 
+                                                                    !the cell list.
+
+        real(kind=dp), intent(in) :: rc_off ! Cutoff radius which dictates the size of the cells
+
+        integer, dimension(3), intent(inout) :: cell_num !Number of cells in each dimension.
+
+        integer, allocatable, intent(inout) :: num_in_cell(:,:,:) !Number of points within each cell
+
+        integer, allocatable, intent(inout) :: cell_list(:,:,:,:) !Index of points from r_list within each cell.
+
+        integer, dimension(3,numinlist), intent(out) :: which_cell !The cell index for each point in r_list
+
+        !----------------------------------------Begin Subroutine -------------------------------------------
+
+        integer :: i, j, cell_lim, c(3)
+        real(kind=dp) :: box_len(3)
+        integer, allocatable :: resize_cell_list(:,:,:,:)
+
+        !First calculate the number of cells that we need in each dimension
+        do i = 1,3
+            box_len(i) = box_bd(2*i) - box_bd(2*i-1)
+            cell_num(i) = int(box_len(i)/(rc_off/2))+1
+        end do 
+
+        !Initialize/allocate variables 
+        cell_lim = 10
+        allocate(num_in_cell(cell_num(1),cell_num(2),cell_num(3)), cell_list(cell_lim, cell_num(1), cell_num(2), cell_num(3)))
+
+        !Now place points within cell
+        do i = 1, numinlist
+            !c is the position of the cell that the point belongs to 
+            do j = 1, 3
+                c(j) = int((r_list(j,i)-box_bd(2*j-1))/(rc_off/2)) + 1
+            end do
+
+            !Place the index in the correct position, growing if necessary
+            num_in_cell(c(1),c(2),c(3)) = num_in_cell(c(1),c(2),c(3)) + 1
+            if (num_in_cell(c(1),c(2),c(3)) > cell_lim) then 
+                allocate(resize_cell_list(cell_lim+10,cell_num(1),cell_num(2),cell_num(3)))
+                resize_cell_list(1:cell_lim, :, :, :) = cell_list
+                resize_cell_list(cell_lim+1:, :, :, :) = 0
+                call move_alloc(resize_cell_list, cell_list)
+            end if
+
+            cell_list(num_in_cell(c(1),c(2),c(3)),c(1),c(2),c(3)) = i
+            which_cell(:,i) = c
+        end do 
+
+        return
+    end subroutine build_cell_list
+
 end module subroutines