How can I install nmslib on Windows 10 - pip

Question

I am trying to install scispacy with pip and found that the installatio of nmslib was causing issues. There are various posts on the internet as to how to fix this, but none seem to be working for me.
I am running Python 3.7.4 on a Windows 10 laptop
Pip is version 19.2.1
Here is error part of the logs
2019-08-08T18:25:20,901 ERROR: Command errored out with exit status 1: 'c:\users\andre\appdata\local\programs\python\python37\python.exe' -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\\Users\\andre\\AppData\\Local\\Temp\\pip-install-y6n2f026\\nmslib\\setup.py'"'"'; __file__='"'"'C:\\Users\\andre\\AppData\\Local\\Temp\\pip-install-y6n2f026\\nmslib\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record 'C:\Users\andre\AppData\Local\Temp\pip-record-90f_5c93\install-record.txt' --single-version-externally-managed --compile Check the logs for full command output.
2019-08-08T18:25:20,902 Exception information:
2019-08-08T18:25:20,902 Traceback (most recent call last):
2019-08-08T18:25:20,902 File "c:\users\andre\appdata\local\programs\python\python37\lib\site-packages\pip\_internal\cli\base_command.py", line 188, in main
2019-08-08T18:25:20,902 status = self.run(options, args)
2019-08-08T18:25:20,902 File "c:\users\andre\appdata\local\programs\python\python37\lib\site-packages\pip\_internal\commands\install.py", line 407, in run
2019-08-08T18:25:20,902 use_user_site=options.use_user_site,
2019-08-08T18:25:20,902 File "c:\users\andre\appdata\local\programs\python\python37\lib\site-packages\pip\_internal\req\__init__.py", line 58, in install_given_reqs
2019-08-08T18:25:20,902 **kwargs
2019-08-08T18:25:20,902 File "c:\users\andre\appdata\local\programs\python\python37\lib\site-packages\pip\_internal\req\req_install.py", line 959, in install
2019-08-08T18:25:20,902 spinner=spinner,
2019-08-08T18:25:20,902 File "c:\users\andre\appdata\local\programs\python\python37\lib\site-packages\pip\_internal\utils\misc.py", line 934, in call_subprocess
2019-08-08T18:25:20,902 raise InstallationError(exc_msg)
2019-08-08T18:25:20,902 pip._internal.exceptions.InstallationError: Command errored out with exit status 1: 'c:\users\andre\appdata\local\programs\python\python37\python.exe' -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\\Users\\andre\\AppData\\Local\\Temp\\pip-install-y6n2f026\\nmslib\\setup.py'"'"'; __file__='"'"'C:\\Users\\andre\\AppData\\Local\\Temp\\pip-install-y6n2f026\\nmslib\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record 'C:\Users\andre\AppData\Local\Temp\pip-record-90f_5c93\install-record.txt' --single-version-externally-managed --compile Check the logs for full command output.
A few weeks ago I had the same issue and amongst the million things I tried I was able to get it to work, but at the time I wasn't entirely sure how I did it. I'm now on a new computer and the issue won't go away.

Answer 1

nmslib is a python wrapper over a c++ library. Therefore it could cause problems on few systems. I had the same issue.
Please clone the repository from here and install manually instead of the pip installation.
Try one of the following.
As per the comments from here,nmslib is optional and is only required if you use it for linker.So you may comment it from the requirements.txt and then do a manual installation via setup.py
Or
In your requirements.txt file add numpy to the top and install via setup.py file.
Though the above steps may throw a VC++ error, the scispacy module will get installed and you will be able to import it.
I tried both the solutions and they worked for me.
Note : Also, from the comments I understand that, now we may directly use spacy and load the scispacy models provided you have downloaded and installed the models.
pip install en_core_sci_sm
import spacy
nlp = spacy.load("en_core_sci_sm")
Let me know which one works for you.