Add example

example/example.f90

@@ -0,0 +1,61 @@
+program graphstruc_example
+  !! Example program for graphstruc
+  use graphstruc, only: graph_type
+  implicit none
+
+  type(graph_type) :: graph
+  integer :: i
+
+  graph%directed = .true.
+  call graph%add_vertex( feature = [ 1.0, 1.0 ] )
+  call graph%add_vertex( feature = [ 1.0, 12.0 ] )
+  call graph%add_edge( &
+       index = [1, -2], weight = 2.0, &
+       feature = [ 1.0, 2.0, 3.0 ], directed = .true. &
+  )
+  write(*,'("Number of vertices:    ",I0)') graph%num_vertices
+  write(*,'("Number of edges:       ",I0)') graph%num_edges
+  write(*,*) 'Directed:', graph%directed
+  write(*,'("Vertex 1 degree:       ",I0)') graph%vertex(1)%degree
+  write(*,'("Vertex 2 degree:       ",I0)') graph%vertex(2)%degree
+
+  write(*,*) 'Adjacency matrix:'
+  do i = 1, graph%num_vertices
+     write(*,*) graph%adjacency(i,:)
+  end do
+  write(*,*)
+
+  write(*,*) "-------------------"
+  write(*,*) "Adding edge"
+  call graph%remove_edges([1])
+  call graph%add_edge( &
+       index = [1, 2], weight = 2.0, &
+       feature = [ 1.0, 2.0, 3.0 ] &
+  )
+  write(*,*) 'Directed:', graph%directed
+  write(*,*) 'Adjacency matrix:'
+  do i = 1, graph%num_vertices
+     write(*,*) graph%adjacency(i,:)
+  end do
+
+  write(*,*) "-------------------"
+  write(*,*) "Resetting graph"
+  call graph%set_num_vertices(4, num_vertex_features = 2)
+  call graph%set_edges(2, [1, 4])
+  write(*,'("Number of vertices:    ",I0)') graph%num_vertices
+  write(*,'("Number of edges:       ",I0)') graph%num_edges
+
+  write(*,*) "-------------------"
+  write(*,*) "Removing vertex 1"
+  call graph%remove_vertices([1, 3])
+  write(*,'("Number of vertices:    ",I0)') graph%num_vertices
+  write(*,'("Number of edges:       ",I0)') graph%num_edges
+
+  write(*,*)
+  write(*,*) "-------------------"
+  write(*,*) "Adding vertex"
+  call graph%add_vertex( feature = [ 1.0, 2.0 ] )
+  write(*,'("Number of vertices:    ",I0)') graph%num_vertices
+  write(*,'("Number of edges:       ",I0)') graph%num_edges
+
+end program graphstruc_example

fpm.toml

@@ -15,3 +15,8 @@ source-dir="src"
 implicit-typing = false
 implicit-external = false
 source-form = "free"
+
+[[example]]
+name = "simple"
+source-dir = "example/"
+main = "example.f90"