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| 1 | +using System; |
| 2 | +using System.Collections.Generic; |
| 3 | +using System.Linq; |
| 4 | +using System.Text; |
| 5 | +using Tensorflow.Keras.Layers; |
| 6 | +using Tensorflow.Keras.Saving; |
| 7 | +using Tensorflow.Keras.Utils; |
| 8 | +using static Tensorflow.Binding; |
| 9 | + |
| 10 | +namespace Tensorflow.Keras.Engine |
| 11 | +{ |
| 12 | + public partial class Functional |
| 13 | + { |
| 14 | + public static Functional from_config(ModelConfig config) |
| 15 | + { |
| 16 | + var (input_tensors, output_tensors, created_layers) = reconstruct_from_config(config); |
| 17 | + var model = new Functional(input_tensors, output_tensors, name: config.Name); |
| 18 | + model.connect_ancillary_layers(created_layers); |
| 19 | + return model; |
| 20 | + } |
| 21 | + |
| 22 | + /// <summary> |
| 23 | + /// Reconstructs graph from config object. |
| 24 | + /// </summary> |
| 25 | + /// <param name="config"></param> |
| 26 | + /// <returns></returns> |
| 27 | + static (Tensors, Tensors, Dictionary<string, ILayer>) reconstruct_from_config(ModelConfig config) |
| 28 | + { |
| 29 | + // Layer instances created during the graph reconstruction process. |
| 30 | + var created_layers = new Dictionary<string, ILayer>(); |
| 31 | + var node_index_map = new Dictionary<(string, int), int>(); |
| 32 | + var node_count_by_layer = new Dictionary<ILayer, int>(); |
| 33 | + var unprocessed_nodes = new Dictionary<ILayer, NodeConfig>(); |
| 34 | + // First, we create all layers and enqueue nodes to be processed |
| 35 | + foreach (var layer_data in config.Layers) |
| 36 | + process_layer(created_layers, layer_data, unprocessed_nodes, node_count_by_layer); |
| 37 | + |
| 38 | + // Then we process nodes in order of layer depth. |
| 39 | + // Nodes that cannot yet be processed (if the inbound node |
| 40 | + // does not yet exist) are re-enqueued, and the process |
| 41 | + // is repeated until all nodes are processed. |
| 42 | + while (unprocessed_nodes.Count > 0) |
| 43 | + { |
| 44 | + foreach(var layer_data in config.Layers) |
| 45 | + { |
| 46 | + var layer = created_layers[layer_data.Name]; |
| 47 | + if (unprocessed_nodes.ContainsKey(layer)) |
| 48 | + { |
| 49 | + var node_data = unprocessed_nodes[layer]; |
| 50 | + // foreach (var node_data in unprocessed_nodes[layer]) |
| 51 | + { |
| 52 | + process_node(layer, node_data, created_layers, node_count_by_layer, node_index_map); |
| 53 | + unprocessed_nodes.Remove(layer); |
| 54 | + } |
| 55 | + } |
| 56 | + } |
| 57 | + } |
| 58 | + |
| 59 | + var input_tensors = new List<Tensor>(); |
| 60 | + foreach (var layer_data in config.InputLayers) |
| 61 | + { |
| 62 | + var (layer_name, node_index, tensor_index) = (layer_data.Name, layer_data.NodeIndex, layer_data.TensorIndex); |
| 63 | + var layer = created_layers[layer_name]; |
| 64 | + var layer_output_tensors = layer.InboundNodes[node_index].Outputs; |
| 65 | + input_tensors.append(layer_output_tensors[tensor_index]); |
| 66 | + } |
| 67 | + |
| 68 | + var output_tensors = new List<Tensor>(); |
| 69 | + foreach (var layer_data in config.OutputLayers) |
| 70 | + { |
| 71 | + var (layer_name, node_index, tensor_index) = (layer_data.Name, layer_data.NodeIndex, layer_data.TensorIndex); |
| 72 | + var layer = created_layers[layer_name]; |
| 73 | + var layer_output_tensors = layer.InboundNodes[node_index].Outputs; |
| 74 | + output_tensors.append(layer_output_tensors[tensor_index]); |
| 75 | + } |
| 76 | + |
| 77 | + return (input_tensors, output_tensors, created_layers); |
| 78 | + } |
| 79 | + |
| 80 | + static void process_layer(Dictionary<string, ILayer> created_layers, |
| 81 | + LayerConfig layer_data, |
| 82 | + Dictionary<ILayer, NodeConfig> unprocessed_nodes, |
| 83 | + Dictionary<ILayer, int> node_count_by_layer) |
| 84 | + { |
| 85 | + ILayer layer = null; |
| 86 | + var layer_name = layer_data.Name; |
| 87 | + if (created_layers.ContainsKey(layer_name)) |
| 88 | + layer = created_layers[layer_name]; |
| 89 | + else |
| 90 | + { |
| 91 | + layer = layer_data.ClassName switch |
| 92 | + { |
| 93 | + "InputLayer" => InputLayer.from_config(layer_data.Config), |
| 94 | + "Dense" => Dense.from_config(layer_data.Config), |
| 95 | + _ => throw new NotImplementedException("") |
| 96 | + }; |
| 97 | + |
| 98 | + created_layers[layer_name] = layer; |
| 99 | + } |
| 100 | + node_count_by_layer[layer] = _should_skip_first_node(layer) ? 1 : 0; |
| 101 | + |
| 102 | + var inbound_nodes_data = layer_data.InboundNodes; |
| 103 | + foreach (var node_data in inbound_nodes_data) |
| 104 | + { |
| 105 | + if (!unprocessed_nodes.ContainsKey(layer)) |
| 106 | + unprocessed_nodes[layer] = node_data; |
| 107 | + else |
| 108 | + unprocessed_nodes.Add(layer, node_data); |
| 109 | + } |
| 110 | + } |
| 111 | + |
| 112 | + static void process_node(ILayer layer, |
| 113 | + NodeConfig node_data, |
| 114 | + Dictionary<string, ILayer> created_layers, |
| 115 | + Dictionary<ILayer, int> node_count_by_layer, |
| 116 | + Dictionary<(string, int), int> node_index_map) |
| 117 | + { |
| 118 | + var input_tensors = new List<Tensor>(); |
| 119 | + var inbound_layer_name = node_data.Name; |
| 120 | + var inbound_node_index = node_data.NodeIndex; |
| 121 | + var inbound_tensor_index = node_data.TensorIndex; |
| 122 | + |
| 123 | + var inbound_layer = created_layers[inbound_layer_name]; |
| 124 | + var inbound_node = inbound_layer.InboundNodes[inbound_node_index]; |
| 125 | + input_tensors.Add(inbound_node.Outputs[inbound_node_index]); |
| 126 | + |
| 127 | + var output_tensors = layer.Apply(input_tensors); |
| 128 | + |
| 129 | + // Update node index map. |
| 130 | + var output_index = output_tensors[0].KerasHistory.NodeIndex; |
| 131 | + node_index_map[(layer.Name, node_count_by_layer[layer])] = output_index; |
| 132 | + node_count_by_layer[layer] += 1; |
| 133 | + } |
| 134 | + |
| 135 | + static bool _should_skip_first_node(ILayer layer) |
| 136 | + { |
| 137 | + return layer is Functional && layer.Layers[0] is InputLayer; |
| 138 | + } |
| 139 | + } |
| 140 | +} |
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