Nupic.core Legacy

Implementation of core NuPIC algorithms in C++ (under construction)
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As of September 2023 this repository contains code from legacy Hierarchical Temporal Memory (HTM) Numenta projects that have been in maintenance mode for several years.

NuPIC Core Unix-like Build Status Windows Build Status CircleCI Coverage Status

This repository contains the C++ source code for the Numenta Platform for Intelligent Computing (NuPIC). It will eventually contain all algorithms for NuPIC, but is currently in a transition period. For details on building NuPIC within the python environment, please see numenta/nupic.

Installing from a Release

You can install the nupic.bindings Python package from PyPI:

pip install nupic.bindings

Optionally include --user or other flags to determine where the package is installed.

Note: On Linux this will do a source installation and will require that the prerequisites specified below are installed.

Building from Source

Important notes:

  • $NUPIC_CORE is the current location of the repository that you downloaded from GitHub.
  • Platform specific text files exist in some external/ subdirectories
  • See the main wiki for more build notes


  • Python - We recommend you use the system version where possibly.
    • Version 2.7
  • NumPy - Can be installed through some system package managers or via pip
    • Version 1.12.1
  • pycapnp
    • Version 0.5.8 (Linux and OSX only)
  • CMake

Note: On Windows, Python package dependencies require the following compiler package to be installed: Microsoft Visual C++ Compiler for Python 2.7

The Python dependencies (NumPy and pycapnp) can be installed with pip:

pip install -r bindings/py/requirements.txt

Simple Source Installation (does not support incremental builds)

The easiest way to build from source is as follows. This does not support incremental builds.

python install

Optionally include --user or other flags to determine where the package is installed.

Testing the Installation

Regardless of how you install nupic.bindings, the nupic-bindings-check command-line script should be installed. Make sure that you include the Python bin installation location in your PATH environment variable and then execute the script:


Developer Installation

This option is for developers that would like the ability to do incremental builds of the C++ or for those that are using the C++ libraries directly.

Note: The following sub-sections are related to Linux and OSX only. For Windows refer to the external\windows64-gcc\ file.

Configure and generate C++ build files:

mkdir -p $NUPIC_CORE/build/scripts
cd $NUPIC_CORE/build/scripts
cmake $NUPIC_CORE -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../release -DPY_EXTENSIONS_DIR=$NUPIC_CORE/bindings/py/src/nupic/bindings


  • This will generate Release build files. For a debug build, change -DCMAKE_BUILD_TYPE to Debug.
  • To build nupic.core for generating the nupic.bindings python extension, pass -DNUPIC_BUILD_PYEXT_MODULES=ON; it is the default at this time.
  • To build nupic.core as a standalone static library, pass -DNUPIC_BUILD_PYEXT_MODULES=OFF.
  • If you have dependencies precompiled but not in standard system locations then you can specify where to find them with -DCMAKE_PREFIX_PATH (for bin/lib) and -DCMAKE_INCLUDE_PATH (for header files).
  • The -DCMAKE_INSTALL_PREFIX=../release option shown above is optional, and specifies the location where nupic.core should be installed. If omitted, nupic.core will be installed in a system location. Using this option is useful when testing versions of nupic.core language bindings in bindings.
  • Setting -DPY_EXTENSIONS_DIR copies the Python exension files to the specified directory. If the extensions aren't present when the Python build/installation is invoked then the file will run the cmake/make process to generate them. Make sure to include this flag if you want to do incremental builds of the Python extensions.
  • On OSX with multiple Python installs (e.g. via brew) cmake might erroneously pick various pieces from different installs which will likely produce abort trap at runtime. Remove cmake cache and re-run cmake with -DPYTHON_LIBRARY=/path/to/lib/libpython2.7.dylib and -DPYTHON_INCLUDE_DIR=/path/to/include/python2.7 options to override with desired Python install path.
  • To use Include What You Use during compilation, pass -DNUPIC-IWYU=ON. This requires that IWYU is installed and findable by CMake, with a minimum CMake version of 3.3. IWYU can be installed from for Windows and Linux, and on OS X using jasonmp85/homebrew-iwyu.
  • If you would like to install all headers, libraries, and executables to the install location for C++ clients when building the nupic.binding python extensions, pass -NUPIC_TOGGLE_INSTALL=ON.


# While still in $NUPIC_CORE/build/scripts
make -j3

Note: The -j3 option specifies '3' as the maximum number of parallel jobs/threads that Make will use during the build in order to gain speed. However, you can increase this number depending your CPU.


# While still in $NUPIC_CORE/build/scripts
make install

Run the tests:

cd $NUPIC_CORE/build/release/bin

Install nupic.bindings Python library:

python develop

Note: If the extensions haven't been built already then this will call the cmake/make process to generate them.

If you get a gcc exit code 1, you may consider running this instead:

 python develop --user

If you are installing on Mac OS X, you must add the instruction ARCHFLAGS="-arch x86_64" before the python call:

ARCHFLAGS="-arch x86_64" python develop

Alternatively, you can use the install command (as opposed to develop) to copy the installation files rather than link to the source location.

python install

Note: If you get a "permission denied" error when using the setup commands above, you may add the --user flag to install to a location in your home directory, which should resolve any permissions issues. Doing this, you may need to add this location to your PATH and PYTHONPATH.

Once it is installed, you can import NuPIC bindings library to your python script using:

import nupic.bindings

You can run the nupic.bindings tests via

python test

Using graphical interface

Generate the IDE solution:

  • Open CMake executable.
  • Specify the source folder ($NUPIC_CORE/src).
  • Specify the build system folder ($NUPIC_CORE/build/scripts), i.e. where IDE solution will be created.
  • Click Generate.
  • Choose the IDE that interest you (remember that IDE choice is limited to your OS, i.e. Visual Studio is available only on CMake for Windows).


  • Open nupic_core.*proj solution file generated on $NUPIC_CORE/build/scripts.
  • Run ALL_BUILD project from your IDE.

Run the tests:

  • Run any tests_* project from your IDE (check output panel to see the results).

Build Documentation

Run doxygen, optionally specifying the version as an environment variable:


The results will be written out to the html directory.

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