Installing numpy with pip on windows 10 for python 3.7

Question

I installed python 3.7 on my Windows 10 laptop since it has been officially released as of today (06/28/2018). Then i tried to install numpy package using pip

pip install numpy

The install proceeds but finally fails with the below error :

        source = func(extension, build_dir)
      File "numpy\core\setup.py", line 675, in get_mathlib_info
        raise RuntimeError("Broken toolchain: cannot link a simple C program")
    RuntimeError: Broken toolchain: cannot link a simple C program

    ----------------------------------------
Command ""c:\program files\python37\python.exe" -u -c "import setuptools, tokenize;__file__='C:\\Users\\pcheg\\AppData\\Local\\Temp\\pip-install-7wjkw5wn\\numpy\\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\pcheg\AppData\Local\Temp\pip-record-uhj8233f\install-record.txt --single-version-externally-managed --compile" failed with error code 1 in C:\Users\pcheg\AppData\Local\Temp\pip-install-7wjkw5wn\numpy\

Any ideas as to how to overcome this install Error? Thanks.

Answer 1

Installing NumPy on Windows is a common problem if you don't have the right build setup. Instead, I always go to Christoph Gohlke's website to download the wheels you can install for your computer. Christoph generously builds the libraries himself with the right build environment and he posts it on his website.

Go to the NumPy section: https://www.lfd.uci.edu/~gohlke/pythonlibs/#numpy then download the version for 3.7 that is compatible with your version of Python (2 or 3 and 32-bit or 64-bit). For example, the filename numpy‑1.14.5+mkl‑cp37‑cp37m‑win_amd64.whl is for NumPy 1.14.5, Python 3.7 - 64 bit. You can pick out which version of NumPy and which version of the Python interpreter and bit version you need in the filename.

Doing this never requires you to build NumPy yourself or install the required compiler as opposed to installing NumPy through PyPI. You can just download the wheel and install it yourself. Assuming you've already downloaded it, just do:

pip install numpy‑1.14.5+mkl‑cp37‑cp37m‑win_amd64.whl

... assuming the wheel is in the directory you're currently in.

Answer 2

You're probably missing a C compiler. If numpy doesn't provide a prebuilt wheel yet, you'll need to install a compiler. This website shows the one you need to install. For 3.7, I assume it's still 14.0, so you should install Microsoft Build Tools for Visual Studio 2017.

Let me know if that works.