tensorflow: Conversion from pb to tflite fails

System information

• Have I written custom code (as opposed to using a stock example script provided in TensorFlow): yes
• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): Windows 10
• Mobile device (e.g. iPhone 8, Pixel 2, Samsung Galaxy) if the issue happens on mobile device:
• TensorFlow installed from (source or binary): binary through pip
• TensorFlow version (use command below): tf-nightly and tf 1.11 (updated today)
• Python version: 3.6.6
• Bazel version (if compiling from source):
• GCC/Compiler version (if compiling from source):
• CUDA/cuDNN version: CPU only
• GPU model and memory:
• Exact command to reproduce:

Describe the problem

I have a trained model and exportet it to a frozen pb file. After that, I optimized this frozen graph for inference. Now I want to convert this graph to a tflite model to use on Android. The code I used to convert it is:

import tensorflow as tf

graph_def_file = "graph_optimized.pb"
input_arrays = ["Placeholder"]
output_arrays = ["output"]

converter = tf.contrib.lite.TocoConverter.from_frozen_graph(
    graph_def_file, input_arrays, output_arrays, input_shapes={"Placeholder" : [1, 227, 227, 3]})
tflite_model = converter.convert()
open("save_path/converted_model.tflite", "wb").write(tflite_model)

This fails with an error. I tried it both with my existing tensorflow installation and with a clean installation in a new virtualenv with tf-nightly like it was suggested in issue #22617 . Still the same errors happen

Source code / logs

WARNING:tensorflow:From C:/Users/User/Documents/Test_export/export.py:8: TocoConverter.from_frozen_graph (from tensorflow.contrib.lite.python.lite) is deprecated and will be removed in a future version.
Instructions for updating:
Use `lite.TFLiteConverter.from_frozen_graph` instead.
2018-10-11 11:57:49.338944: I tensorflow/core/platform/cpu_feature_guard.cc:141] Your CPU supports instructions that this TensorFlow binary was not compiled to use: AVX2
Traceback (most recent call last):
  File "C:/Users/User/Documents/Test_export/export.py", line 9, in <module>
    tflite_model = converter.convert()
  File "C:\Users\User\venv-tf-nightly\lib\site-packages\tensorflow\contrib\lite\python\lite.py", line 453, in convert
    **converter_kwargs)
  File "C:\Users\User\venv-tf-nightly\lib\site-packages\tensorflow\contrib\lite\python\convert.py", line 348, in toco_convert_impl
    input_data.SerializeToString())
  File "C:\Users\User\venv-tf-nightly\lib\site-packages\tensorflow\contrib\lite\python\convert.py", line 135, in toco_convert_protos
    (stdout, stderr))
RuntimeError: TOCO failed see console for info.
b'Traceback (most recent call last):\r\n  File "c:\\users\\user\\appdata\\local\\programs\\python\\python36\\lib\\site-packages\\tensorflow\\contrib\\lite\\toco\\python\\tensorflow_wrap_toco.py", line 18, in swig_import_helper\r\n    fp, pathname, description = imp.find_module(\'_tensorflow_wrap_toco\', [dirname(__file__)])\r\n  File "c:\\users\\user\\appdata\\local\\programs\\python\\python36\\lib\\imp.py", line 297, in find_module\r\n    raise ImportError(_ERR_MSG.format(name), name=name)\r\nImportError: No module named \'_tensorflow_wrap_toco\'\r\n\r\nDuring handling of the above exception, another exception occurred:\r\n\r\nTraceback (most recent call last):\r\n  File "c:\\users\\user\\appdata\\local\\programs\\python\\python36\\lib\\runpy.py", line 193, in _run_module_as_main\r\n    "__main__", mod_spec)\r\n  File "c:\\users\\user\\appdata\\local\\programs\\python\\python36\\lib\\runpy.py", line 85, in _run_code\r\n    exec(code, run_globals)\r\n  File "C:\\Users\\User\\AppData\\Local\\Programs\\Python\\Python36\\Scripts\\toco_from_protos.exe\\__main__.py", line 5, in <module>\r\n  File "c:\\users\\user\\appdata\\local\\programs\\python\\python36\\lib\\site-packages\\tensorflow\\contrib\\lite\\toco\\python\\toco_from_protos.py", line 22, in <module>\r\n    from tensorflow.contrib.lite.toco.python import tensorflow_wrap_toco\r\n  File "c:\\users\\user\\appdata\\local\\programs\\python\\python36\\lib\\site-packages\\tensorflow\\contrib\\lite\\toco\\python\\tensorflow_wrap_toco.py", line 28, in <module>\r\n    _tensorflow_wrap_toco = swig_import_helper()\r\n  File "c:\\users\\user\\appdata\\local\\programs\\python\\python36\\lib\\site-packages\\tensorflow\\contrib\\lite\\toco\\python\\tensorflow_wrap_toco.py", line 20, in swig_import_helper\r\n    import _tensorflow_wrap_toco\r\nModuleNotFoundError: No module named \'_tensorflow_wrap_toco\'\r\n'
None


Process finished with exit code 1