mamba, an experiment to make conda faster

Mamba is a reimplementation of the bits which are somewhat slow in conda. Mamba uses:

• parallel downloading of JSON files using multiprocessing, and reusing conda's caches
• libsolv for speedy dependency solving, a state of the art library used in the package manager of Fedora and others

At the same time, mamba re-uses a lot of conda's codebase to parse the command line and execute the transaction (installation & deinstallation of packages).

Installation

From conda-forge:

conda install mamba -c conda-forge

From Source:

Make sure to have the following requirements in your conda environment:

• conda install cmake compilers pybind11 libsolv libarchive libcurl nlohmann_json pip -c conda-forge

If you build mamba in a different environment than base, you must also install conda in that environment:

• conda install conda -c conda-forge

For a local (dev) build, run pip install -e .. This will build and install mamba in the conda environment.

Installing conda packages with mamba

Now you are ready to install packages with

mamba install xtensor-r -c conda-forge

for example.

Additional features

Mamba comes with features on top of stock conda. To efficiently query repositories and query package dependencies you can use mamba repoquery.

Here are some examples:

mamba repoquery search xtensor will show you all available xtensor packages. You can also specify more constraints on this search query, for example mamba repoquery search "xtensor>=0.18"

mamba repoquery depends xtensor will show you a tree view of the dependencies of xtensor.

$ mamba repoquery depends xtensor

xtensor == 0.21.5
  ├─ libgcc-ng [>=7.3.0]
  │ ├─ _libgcc_mutex [0.1 conda_forge]
  │ └─ _openmp_mutex [>=4.5]
  │   ├─ _libgcc_mutex already visited
  │   └─ libgomp [>=7.3.0]
  │     └─ _libgcc_mutex already visited
  ├─ libstdcxx-ng [>=7.3.0]
  └─ xtl [>=0.6.9,<0.7]
    ├─ libgcc-ng already visited
    └─ libstdcxx-ng already visited

And you can ask for the inverse, which packages depend on some other package (e.g. ipython) using whoneeds.

$ mamba repoquery whoneeds ipython

 Name            Version Build          Channel
──────────────────────────────────────────────────
 ipykernel       5.2.1   py37h43977f1_0 installed
 ipywidgets      7.5.1   py_0           installed
 jupyter_console 6.1.0   py_1           installed

With the --tree (or -t) flag, you can get the same information in a tree.

Development installation

You first need to install the mamba dependencies:

conda install -c conda-forge python=3.7 pybind11 nlohmann_json cmake

For the C++ tests, you need Google Tests installed (e.g. conda install gtest). To build the program using CMake, the following line needs to be used:

cmake .. \
  -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX \
  -DPYTHON_EXECUTABLE=$CONDA_PREFIX/bin/python3 \
  -DPYTHON_LIBRARIES=$CONDA_PREFIX/lib/libpython3.7m.so \
  -DENABLE_TESTS=ON

Support us

For questions, you can also join us on QuantStack Chat or on the conda channel (note that this project is not officially affiliated with conda or Anaconda Inc.).