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      1 /*
      2 Copyright 2017 The TensorFlow Authors. All Rights Reserved.
      3 
      4 Licensed under the Apache License, Version 2.0 (the "License");
      5 you may not use this file except in compliance with the License.
      6 You may obtain a copy of the License at
      7 
      8     http://www.apache.org/licenses/LICENSE-2.0
      9 
     10 Unless required by applicable law or agreed to in writing, software
     11 distributed under the License is distributed on an "AS IS" BASIS,
     12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 See the License for the specific language governing permissions and
     14 limitations under the License.
     15 */
     16 
     17 package tensorflow
     18 
     19 import (
     20 	"runtime"
     21 	"unsafe"
     22 )
     23 
     24 // #include <stdlib.h>
     25 // #include "tensorflow/c/c_api.h"
     26 import "C"
     27 
     28 // SavedModel represents the contents of loaded SavedModel.
     29 // TODO(jhseu): Add and document metagraphdef when we pregenerate protobufs.
     30 type SavedModel struct {
     31 	Session *Session
     32 	Graph   *Graph
     33 }
     34 
     35 // LoadSavedModel creates a new SavedModel from a model previously
     36 // exported to a directory on disk.
     37 //
     38 // Exported models contain a set of graphs and, optionally, variable values.
     39 // Tags in the model identify a single graph. LoadSavedModel initializes a
     40 // session with the identified graph and with variables initialized to from the
     41 // checkpoints on disk.
     42 //
     43 // The tensorflow package currently does not have the ability to export a model
     44 // to a directory from Go. This function thus currently targets loading models
     45 // exported in other languages, such as using tf.saved_model.builder in Python.
     46 // See:
     47 // https://www.tensorflow.org/code/tensorflow/python/saved_model/
     48 func LoadSavedModel(exportDir string, tags []string, options *SessionOptions) (*SavedModel, error) {
     49 	status := newStatus()
     50 	cOpt, doneOpt, err := options.c()
     51 	defer doneOpt()
     52 	if err != nil {
     53 		return nil, err
     54 	}
     55 	cExportDir := C.CString(exportDir)
     56 	cTags := make([]*C.char, len(tags))
     57 	for i := range tags {
     58 		cTags[i] = C.CString(tags[i])
     59 	}
     60 	graph := NewGraph()
     61 	// TODO(jhseu): Add support for run_options and meta_graph_def.
     62 	cSess := C.TF_LoadSessionFromSavedModel(cOpt, nil, cExportDir, (**C.char)(unsafe.Pointer(&cTags[0])), C.int(len(cTags)), graph.c, nil, status.c)
     63 	for i := range cTags {
     64 		C.free(unsafe.Pointer(cTags[i]))
     65 	}
     66 	C.free(unsafe.Pointer(cExportDir))
     67 
     68 	if err := status.Err(); err != nil {
     69 		return nil, err
     70 	}
     71 	s := &Session{c: cSess}
     72 	runtime.SetFinalizer(s, func(s *Session) { s.Close() })
     73 	return &SavedModel{Session: s, Graph: graph}, nil
     74 }
     75