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Diffstat (limited to 'source/blender/functions/intern/multi_function_network_optimization.cc')
| -rw-r--r-- | source/blender/functions/intern/multi_function_network_optimization.cc | 491 |
1 files changed, 491 insertions, 0 deletions
diff --git a/source/blender/functions/intern/multi_function_network_optimization.cc b/source/blender/functions/intern/multi_function_network_optimization.cc new file mode 100644 index 00000000000..849b24a318f --- /dev/null +++ b/source/blender/functions/intern/multi_function_network_optimization.cc @@ -0,0 +1,491 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +/** \file + * \ingroup fn + */ + +/* Used to check if two multi-functions have the exact same type. */ +#include <typeinfo> + +#include "FN_multi_function_builder.hh" +#include "FN_multi_function_network_evaluation.hh" +#include "FN_multi_function_network_optimization.hh" + +#include "BLI_disjoint_set.hh" +#include "BLI_ghash.h" +#include "BLI_map.hh" +#include "BLI_rand.h" +#include "BLI_stack.hh" + +namespace blender::fn::mf_network_optimization { + +/* -------------------------------------------------------------------- */ +/** \name Utility functions to find nodes in a network. + * + * \{ */ + +static bool set_tag_and_check_if_modified(bool &tag, bool new_value) +{ + if (tag != new_value) { + tag = new_value; + return true; + } + else { + return false; + } +} + +static Array<bool> mask_nodes_to_the_left(MFNetwork &network, Span<MFNode *> nodes) +{ + Array<bool> is_to_the_left(network.node_id_amount(), false); + Stack<MFNode *> nodes_to_check; + + for (MFNode *node : nodes) { + is_to_the_left[node->id()] = true; + nodes_to_check.push(node); + } + + while (!nodes_to_check.is_empty()) { + MFNode &node = *nodes_to_check.pop(); + + for (MFInputSocket *input_socket : node.inputs()) { + MFOutputSocket *origin = input_socket->origin(); + if (origin != nullptr) { + MFNode &origin_node = origin->node(); + if (set_tag_and_check_if_modified(is_to_the_left[origin_node.id()], true)) { + nodes_to_check.push(&origin_node); + } + } + } + } + + return is_to_the_left; +} + +static Array<bool> mask_nodes_to_the_right(MFNetwork &network, Span<MFNode *> nodes) +{ + Array<bool> is_to_the_right(network.node_id_amount(), false); + Stack<MFNode *> nodes_to_check; + + for (MFNode *node : nodes) { + is_to_the_right[node->id()] = true; + nodes_to_check.push(node); + } + + while (!nodes_to_check.is_empty()) { + MFNode &node = *nodes_to_check.pop(); + + for (MFOutputSocket *output_socket : node.outputs()) { + for (MFInputSocket *target_socket : output_socket->targets()) { + MFNode &target_node = target_socket->node(); + if (set_tag_and_check_if_modified(is_to_the_right[target_node.id()], true)) { + nodes_to_check.push(&target_node); + } + } + } + } + + return is_to_the_right; +} + +static Vector<MFNode *> find_nodes_based_on_mask(MFNetwork &network, + Span<bool> id_mask, + bool mask_value) +{ + Vector<MFNode *> nodes; + for (uint id : id_mask.index_range()) { + if (id_mask[id] == mask_value) { + MFNode *node = network.node_or_null_by_id(id); + if (node != nullptr) { + nodes.append(node); + } + } + } + return nodes; +} + +/** \} */ + +/* -------------------------------------------------------------------- */ +/** \name Dead Node Removal + * + * \{ */ + +/** + * Unused nodes are all those nodes that no dummy node depends upon. + */ +void dead_node_removal(MFNetwork &network) +{ + Array<bool> node_is_used_mask = mask_nodes_to_the_left(network, network.dummy_nodes()); + Vector<MFNode *> nodes_to_remove = find_nodes_based_on_mask(network, node_is_used_mask, false); + network.remove(nodes_to_remove); +} + +/** \} */ + +/* -------------------------------------------------------------------- */ +/** \name Constant Folding + * + * \{ */ + +static Vector<MFNode *> find_non_constant_nodes(MFNetwork &network) +{ + Vector<MFNode *> non_constant_nodes; + non_constant_nodes.extend(network.dummy_nodes()); + + for (MFFunctionNode *node : network.function_nodes()) { + if (!node->all_inputs_have_origin()) { + non_constant_nodes.append(node); + } + } + return non_constant_nodes; +} + +static bool output_has_non_constant_target_node(MFOutputSocket *output_socket, + Span<bool> is_not_constant_mask) +{ + for (MFInputSocket *target_socket : output_socket->targets()) { + MFNode &target_node = target_socket->node(); + bool target_is_not_constant = is_not_constant_mask[target_node.id()]; + if (target_is_not_constant) { + return true; + } + } + return false; +} + +static MFInputSocket *try_find_dummy_target_socket(MFOutputSocket *output_socket) +{ + for (MFInputSocket *target_socket : output_socket->targets()) { + if (target_socket->node().is_dummy()) { + return target_socket; + } + } + return nullptr; +} + +static Vector<MFInputSocket *> find_constant_inputs_to_fold( + MFNetwork &network, Vector<MFDummyNode *> &r_temporary_nodes) +{ + Vector<MFNode *> non_constant_nodes = find_non_constant_nodes(network); + Array<bool> is_not_constant_mask = mask_nodes_to_the_right(network, non_constant_nodes); + Vector<MFNode *> constant_nodes = find_nodes_based_on_mask(network, is_not_constant_mask, false); + + Vector<MFInputSocket *> sockets_to_compute; + for (MFNode *node : constant_nodes) { + if (node->inputs().size() == 0) { + continue; + } + + for (MFOutputSocket *output_socket : node->outputs()) { + MFDataType data_type = output_socket->data_type(); + if (output_has_non_constant_target_node(output_socket, is_not_constant_mask)) { + MFInputSocket *dummy_target = try_find_dummy_target_socket(output_socket); + if (dummy_target == nullptr) { + dummy_target = &network.add_output("Dummy", data_type); + network.add_link(*output_socket, *dummy_target); + r_temporary_nodes.append(&dummy_target->node().as_dummy()); + } + + sockets_to_compute.append(dummy_target); + } + } + } + return sockets_to_compute; +} + +static void prepare_params_for_constant_folding(const MultiFunction &network_fn, + MFParamsBuilder ¶ms, + ResourceCollector &resources) +{ + for (uint param_index : network_fn.param_indices()) { + MFParamType param_type = network_fn.param_type(param_index); + MFDataType data_type = param_type.data_type(); + + switch (data_type.category()) { + case MFDataType::Single: { + /* Allocates memory for a single constant folded value. */ + const CPPType &cpp_type = data_type.single_type(); + void *buffer = resources.linear_allocator().allocate(cpp_type.size(), + cpp_type.alignment()); + GMutableSpan array{cpp_type, buffer, 1}; + params.add_uninitialized_single_output(array); + break; + } + case MFDataType::Vector: { + /* Allocates memory for a constant folded vector. */ + const CPPType &cpp_type = data_type.vector_base_type(); + GVectorArray &vector_array = resources.construct<GVectorArray>(AT, cpp_type, 1); + params.add_vector_output(vector_array); + break; + } + } + } +} + +static Array<MFOutputSocket *> add_constant_folded_sockets(const MultiFunction &network_fn, + MFParamsBuilder ¶ms, + ResourceCollector &resources, + MFNetwork &network) +{ + Array<MFOutputSocket *> folded_sockets{network_fn.param_indices().size(), nullptr}; + + for (uint param_index : network_fn.param_indices()) { + MFParamType param_type = network_fn.param_type(param_index); + MFDataType data_type = param_type.data_type(); + + const MultiFunction *constant_fn = nullptr; + + switch (data_type.category()) { + case MFDataType::Single: { + const CPPType &cpp_type = data_type.single_type(); + GMutableSpan array = params.computed_array(param_index); + void *buffer = array.buffer(); + resources.add(buffer, array.type().destruct_cb(), AT); + + constant_fn = &resources.construct<CustomMF_GenericConstant>(AT, cpp_type, buffer); + break; + } + case MFDataType::Vector: { + GVectorArray &vector_array = params.computed_vector_array(param_index); + GSpan array = vector_array[0]; + constant_fn = &resources.construct<CustomMF_GenericConstantArray>(AT, array); + break; + } + } + + MFFunctionNode &folded_node = network.add_function(*constant_fn); + folded_sockets[param_index] = &folded_node.output(0); + } + return folded_sockets; +} + +static Array<MFOutputSocket *> compute_constant_sockets_and_add_folded_nodes( + MFNetwork &network, + Span<const MFInputSocket *> sockets_to_compute, + ResourceCollector &resources) +{ + MFNetworkEvaluator network_fn{{}, sockets_to_compute}; + + MFContextBuilder context; + MFParamsBuilder params{network_fn, 1}; + prepare_params_for_constant_folding(network_fn, params, resources); + network_fn.call({0}, params, context); + return add_constant_folded_sockets(network_fn, params, resources, network); +} + +/** + * Find function nodes that always output the same value and replace those with constant nodes. + */ +void constant_folding(MFNetwork &network, ResourceCollector &resources) +{ + Vector<MFDummyNode *> temporary_nodes; + Vector<MFInputSocket *> inputs_to_fold = find_constant_inputs_to_fold(network, temporary_nodes); + if (inputs_to_fold.size() == 0) { + return; + } + + Array<MFOutputSocket *> folded_sockets = compute_constant_sockets_and_add_folded_nodes( + network, inputs_to_fold, resources); + + for (uint i : inputs_to_fold.index_range()) { + MFOutputSocket &original_socket = *inputs_to_fold[i]->origin(); + network.relink(original_socket, *folded_sockets[i]); + } + + network.remove(temporary_nodes); +} + +/** \} */ + +/* -------------------------------------------------------------------- */ +/** \name Common Sub-network Elimination + * + * \{ */ + +static uint32_t compute_node_hash(MFFunctionNode &node, RNG *rng, Span<uint32_t> node_hashes) +{ + uint32_t combined_inputs_hash = 394659347u; + for (MFInputSocket *input_socket : node.inputs()) { + MFOutputSocket *origin_socket = input_socket->origin(); + uint32_t input_hash; + if (origin_socket == nullptr) { + input_hash = BLI_rng_get_uint(rng); + } + else { + input_hash = BLI_ghashutil_combine_hash(node_hashes[origin_socket->node().id()], + origin_socket->index()); + } + combined_inputs_hash = BLI_ghashutil_combine_hash(combined_inputs_hash, input_hash); + } + + uint32_t function_hash = node.function().hash(); + uint32_t node_hash = BLI_ghashutil_combine_hash(combined_inputs_hash, function_hash); + return node_hash; +} + +/** + * Produces a hash for every node. Two nodes with the same hash should have a high probability of + * outputting the same values. + */ +static Array<uint32_t> compute_node_hashes(MFNetwork &network) +{ + RNG *rng = BLI_rng_new(0); + Array<uint32_t> node_hashes(network.node_id_amount()); + Array<bool> node_is_hashed(network.node_id_amount(), false); + + /* No dummy nodes are not assumed to output the same values. */ + for (MFDummyNode *node : network.dummy_nodes()) { + uint32_t node_hash = BLI_rng_get_uint(rng); + node_hashes[node->id()] = node_hash; + node_is_hashed[node->id()] = true; + } + + Stack<MFFunctionNode *> nodes_to_check; + nodes_to_check.push_multiple(network.function_nodes()); + + while (!nodes_to_check.is_empty()) { + MFFunctionNode &node = *nodes_to_check.peek(); + if (node_is_hashed[node.id()]) { + nodes_to_check.pop(); + continue; + } + + /* Make sure that origin nodes are hashed first. */ + bool all_dependencies_ready = true; + for (MFInputSocket *input_socket : node.inputs()) { + MFOutputSocket *origin_socket = input_socket->origin(); + if (origin_socket != nullptr) { + MFNode &origin_node = origin_socket->node(); + if (!node_is_hashed[origin_node.id()]) { + all_dependencies_ready = false; + nodes_to_check.push(&origin_node.as_function()); + } + } + } + if (!all_dependencies_ready) { + continue; + } + + uint32_t node_hash = compute_node_hash(node, rng, node_hashes); + node_hashes[node.id()] = node_hash; + node_is_hashed[node.id()] = true; + nodes_to_check.pop(); + } + + BLI_rng_free(rng); + return node_hashes; +} + +static Map<uint32_t, Vector<MFNode *, 1>> group_nodes_by_hash(MFNetwork &network, + Span<uint32_t> node_hashes) +{ + Map<uint32_t, Vector<MFNode *, 1>> nodes_by_hash; + for (uint id : IndexRange(network.node_id_amount())) { + MFNode *node = network.node_or_null_by_id(id); + if (node != nullptr) { + uint32_t node_hash = node_hashes[id]; + nodes_by_hash.lookup_or_add_default(node_hash).append(node); + } + } + return nodes_by_hash; +} + +static bool functions_are_equal(const MultiFunction &a, const MultiFunction &b) +{ + if (&a == &b) { + return true; + } + if (typeid(a) == typeid(b)) { + return a.equals(b); + } + return false; +} + +static bool nodes_output_same_values(DisjointSet &cache, const MFNode &a, const MFNode &b) +{ + if (cache.in_same_set(a.id(), b.id())) { + return true; + } + + if (a.is_dummy() || b.is_dummy()) { + return false; + } + if (!functions_are_equal(a.as_function().function(), b.as_function().function())) { + return false; + } + for (uint i : a.inputs().index_range()) { + const MFOutputSocket *origin_a = a.input(i).origin(); + const MFOutputSocket *origin_b = b.input(i).origin(); + if (origin_a == nullptr || origin_b == nullptr) { + return false; + } + if (!nodes_output_same_values(cache, origin_a->node(), origin_b->node())) { + return false; + } + } + + cache.join(a.id(), b.id()); + return true; +} + +static void relink_duplicate_nodes(MFNetwork &network, + Map<uint32_t, Vector<MFNode *, 1>> &nodes_by_hash) +{ + DisjointSet same_node_cache{network.node_id_amount()}; + + for (Span<MFNode *> nodes_with_same_hash : nodes_by_hash.values()) { + if (nodes_with_same_hash.size() <= 1) { + continue; + } + + Vector<MFNode *, 16> nodes_to_check = nodes_with_same_hash; + while (nodes_to_check.size() >= 2) { + Vector<MFNode *, 16> remaining_nodes; + + MFNode &deduplicated_node = *nodes_to_check[0]; + for (MFNode *node : nodes_to_check.as_span().drop_front(1)) { + /* This is true with fairly high probability, but hash collisions can happen. So we have to + * check if the node actually output the same values. */ + if (nodes_output_same_values(same_node_cache, deduplicated_node, *node)) { + for (uint i : deduplicated_node.outputs().index_range()) { + network.relink(node->output(i), deduplicated_node.output(i)); + } + } + else { + remaining_nodes.append(node); + } + } + nodes_to_check = std::move(remaining_nodes); + } + } +} + +/** + * Tries to detect duplicate sub-networks and eliminates them. This can help quite a lot when node + * groups were used to create the network. + */ +void common_subnetwork_elimination(MFNetwork &network) +{ + Array<uint32_t> node_hashes = compute_node_hashes(network); + Map<uint32_t, Vector<MFNode *, 1>> nodes_by_hash = group_nodes_by_hash(network, node_hashes); + relink_duplicate_nodes(network, nodes_by_hash); +} + +/** \} */ + +} // namespace blender::fn::mf_network_optimization |