Abstract neighborlists layout

Signed-off-by: Rafael Ravedutti <[email protected]>

backend/mapping_cpu.impala

@@ -1,9 +1,4 @@
-fn @is_nvvm() -> bool { false }
-fn @is_cuda() -> bool { false }
-fn @is_opencl() -> bool { false }
-fn @is_amdgpu() -> bool { false }
-fn @has_ldg() -> bool { false }
-
+fn @NeighborlistLayout() -> ArrayLayout { column_major_order_array(0) }
 type dev_i32_ptr = &mut i32;
 
 fn @device() -> Device {
@@ -87,7 +82,3 @@ fn @reduce_aabb(n: i32, b: AABB, reduce: fn(AABB, AABB) -> AABB, body: fn(i32) -
 
     red
 }
-
-fn @get_neighborlist_index(particle_index: i32, neighbor_index: i32, grid: Grid) -> i32 {
-    grid.neighborlist_capacity * particle_index + neighbor_index
-}

backend/mapping_gpu.impala

@@ -1,8 +1,4 @@
-fn @is_x86() -> bool { false }
-fn @is_sse() -> bool { false }
-fn @is_avx() -> bool { false }
-fn @is_avx2() -> bool { false }
-
+fn @NeighborlistLayout() -> ArrayLayout { row_major_order_array(0) }
 type dev_i32_ptr = &mut[1]i32;
 
 struct ReductionBuffers {
@@ -222,7 +218,3 @@ fn @reduce_aabb(n: i32, b: AABB, reduce: fn(AABB, AABB) -> AABB, body: fn(i32) -
 
     red
 }
-
-fn get_neighborlist_index(particle_index: i32, neighbor_index: i32, grid: Grid) -> i32 {
-    grid.particle_capacity * neighbor_index + particle_index
-}

core/compute.impala

@@ -23,7 +23,7 @@ fn @(?half_nb) compute_potential(
         let pos_i = get_position(i, grid);
 
         for n in range(0, nb_list_size) {
-            let j = neighborlists(get_neighborlist_index(i, n, grid));
+            let j = array_2d_get_i32(array_dev, NeighborlistLayout(), grid.neighborlists, i, n);
             let pos_j = get_position(j, grid);
             let del = vector_sub(pos_i, pos_j);
             let rsq = vector_len2(del);

core/layouts.impala

@@ -130,6 +130,14 @@ fn @array_2d_get_real(@target_fn: ArrayTargetFn, @layout: ArrayLayout, array: Ar
     bitcast[&[real_t]](target_fn(array).data)(layout.index_2d_fn(array, i, j))
 }
 
+fn @array_2d_set_i32(@target_fn: ArrayTargetFn, @layout: ArrayLayout, array: ArrayData, i: i32, j: i32, value: i32) -> () {
+    bitcast[&mut[i32]](target_fn(array).data)(layout.index_2d_fn(array, i, j)) = value;
+}
+
+fn @array_2d_get_i32(@target_fn: ArrayTargetFn, @layout: ArrayLayout, array: ArrayData, i: i32, j: i32) -> i32 {
+    bitcast[&[i32]](target_fn(array).data)(layout.index_2d_fn(array, i, j))
+}
+
 fn @array_2d_add_real(@layout: ArrayLayout, array: ArrayData, i: i32, j: i32, value: real_t) -> () {
     layout.add_fn(array, layout.index_2d_fn(array, i, j), value);
 }

core/neighborlist.impala

@@ -16,14 +16,13 @@ fn @(?half_nb) neighbor_cells(index: i32, nx: i32, ny: i32, ncells: i32, half_nb
 }
 
 fn @append_neighbor(grid: Grid, particle_index: i32, neighbor_index: i32) -> () {
-    let neighborlists = get_array_i32_ref(array_dev, grid.neighborlists);
     let neighbors_sizes = get_array_i32_ref(array_dev, grid.neighbors_sizes);
     let nb_list_size = neighbors_sizes(particle_index);
 
     if nb_list_size >= grid.neighborlist_capacity {
         grow_resize(nb_list_size, grid);
     } else {
-        neighborlists(get_neighborlist_index(particle_index, nb_list_size, grid)) = neighbor_index;
+        array_2d_set_i32(array_dev, NeighborlistLayout(), grid.neighborlists, particle_index, nb_list_size, neighbor_index);
     }
 
     neighbors_sizes(particle_index)++;