How to fix ' ImportError: cannot import name 'numpy_type_map' ' in Python?
I've followed the instructions in Detectron and I've configured it several times: the code compiles as it should. When it comes to run the code, I get this error:

    Traceback (most recent call last):
    File "tools/train_net_step.py", line 21, in &lt;module&gt;
    import nn as mynn
    File "/home/federico/PycharmProjects/Detectron.pytorch/lib/nn/__init__.py", line 2, in &lt;module&gt;
    from .parallel import DataParallel
    File "/home/federico/PycharmProjects/Detectron.pytorch/lib/nn/parallel/__init__.py", line 3, in &lt;module&gt;
    from .data_parallel import DataParallel, data_parallel
    File "/home/federico/PycharmProjects/Detectron.pytorch/lib/nn/parallel/data_parallel.py", line 4, in &lt;module&gt;
    from .scatter_gather import scatter_kwargs, gather
    File "/home/federico/PycharmProjects/Detectron.pytorch/lib/nn/parallel/scatter_gather.py", line 8, in &lt;module&gt;
    from torch.utils.data.dataloader import numpy_type_map
    ImportError: cannot import name 'numpy_type_map'


I've also tried to google it many times, but I can't find a way to solve it. What can I do? I'm using PyTorch 0.4.1 and pytorch nightly 1.0.0-dev.

EDIT: Thanks to sancelot, I managed to solve that error (PyTorch 0.4.0 did the thing). Anyway, now I've got another error: 

    Traceback (most recent call last):
    File "tools/train_net_step.py", line 27, in &lt;module&gt;
    from modeling.model_builder import Generalized_RCNN
    File "/home/federico/PycharmProjects/Detectron.pytorch/lib/modeling/model_builder.py", line 11, in &lt;module&gt;
    from model.roi_pooling.functions.roi_pool import RoIPoolFunction
    File "/home/federico/PycharmProjects/Detectron.pytorch/lib/model/roi_pooling/functions/roi_pool.py", line 3, in &lt;module&gt;
    from .._ext import roi_pooling
    File "/home/federico/PycharmProjects/Detectron.pytorch/lib/model/roi_pooling/_ext/roi_pooling/__init__.py", line 3, in &lt;module&gt;
    from ._roi_pooling import lib as _lib, ffi as _ffi
    ImportError: /home/federico/PycharmProjects/Detectron.pytorch/lib/model/roi_pooling/_ext/roi_pooling/_roi_pooling.so: undefined symbol: PyInt_FromLong


What I can't get this time is: is this an error given by an external library? I'm using an anaconda environment previously made by my professor, who has used it for Detectron... so I can't guess why I get this.

I suppose there is a version mismatch between detectron and the needed pytorch release you are using.
if you look at latest pytorch source code, there is no numpy_type_map component.
https://github.com/pytorch/pytorch/blob/master/torch/utils/data/dataloader.py
