RAFT: RAPIDS Analytics Framework Toolkit

RAFT is a library containing building-blocks for rapid composition of RAPIDS Analytics. These building-blocks include shared representations, mathematical computational primitives, and utilities that accelerate building analytics and data science algorithms in the RAPIDS ecosystem. Both the C++ and Python components can be included in consuming libraries, providing building-blocks for both dense and sparse matrix formats in the following general categories:

Category	Description / Examples
Data Formats	tensor representations and conversions for both sparse and dense formats
Data Generation	graph, spatial, and machine learning dataset generation
Dense Operations	linear algebra, statistics
Spatial	pairwise distances, nearest neighbors, neighborhood / proximity graph construction
Sparse/Graph Operations	linear algebra, statistics, slicing, msf, spectral embedding/clustering, slhc, vertex degree
Solvers	eigenvalue decomposition, least squares, lanczos
Tools	multi-node multi-gpu communicator, utilities

By taking a primitives-based approach to algorithm development, RAFT accelerates algorithm construction time and reduces the maintenance burden by maximizing reuse across projects. RAFT relies on the RAPIDS memory manager (RMM) which, like other projects in the RAPIDS ecosystem, eases the burden of configuring different allocation strategies globally across the libraries that use it. RMM also provides RAII wrappers around device arrays that handle the allocation and cleanup.

Getting started

Refer to the Build and Development Guide for details on RAFT's design, building, testing and development guidelines.

Most of the primitives in RAFT accept a raft::handle_t object for the management of resources which are expensive to create, such CUDA streams, stream pools, and handles to other CUDA libraries like cublas and cusolver.

C++ Example

The example below demonstrates creating a RAFT handle and using it with RMM's device_uvector to allocate memory on device and compute pairwise Euclidean distances:

#include <raft/handle.hpp>
#include <raft/distance/distance.hpp>

#include <rmm/device_uvector.hpp>
raft::handle_t handle;

int n_samples = ...;
int n_features = ...;

rmm::device_uvector<float> input(n_samples * n_features, handle.get_stream());
rmm::device_uvector<float> output(n_samples * n_samples, handle.get_stream());

// ... Populate feature matrix ...

auto metric = raft::distance::DistanceType::L2SqrtExpanded;
rmm::device_uvector<char> workspace(0, handle.get_stream());
raft::distance::pairwise_distance(handle, input.data(), input.data(),
                                  output.data(),
                                  n_samples, n_samples, n_features,
                                  workspace.data(), metric);

Folder Structure and Contents

The folder structure mirrors other RAPIDS repos (cuDF, cuML, cuGraph...), with the following folders:

• cpp: Source code for all C++ code. The code is currently header-only, therefore it is in the include folder (with no src).
• python: Source code for all Python source code.
• ci: Scripts for running CI in PRs