This repository implements an end-to-end stack that compiles a high-level description of a stencil program to hardware. Dependencies between stencil operators are resolved by streaming fine-grained results directly between processing elements on the chip.

To run the code, the following software must be available:

• Python 3.6.x or newer.
• The virtualenv module (installed with pip install virtualenv).
• A C++17-capable compiler (e.g., GCC 7.x or Clang 6.x).
• One or both FPGA compilers:
  • Intel FPGA OpenCL SDK (tested with 18.1.1 and 19.1)
  • Xilinx Vitis (tested with 2020.2)

Sourcing the script setup_virtualenv.sh will setup a virtualenv with all the modules required to run StencilFlow, including the relevant version of DaCe:

source setup_virtualenv.sh

To run the end-to-end flow on an input JSON file, the executable bin/run_program.py can be used. Example usage:

bin/run_program.py test/stencils/jacobi3d_32x32x32_8itr_8vec.json emulation -compare-to-reference

This will compile the FPGA kernel for Intel's emulation flow, execute it, build a reference CPU program, run both, and verify that the results match.

The generated program will be located in .dacecache/<kernel name>, with the kernel source files themselves in:

.dacecache/<kernel name>/src/intel_fpga/device

For programs using the "shrink" boundary conditions, the borders will intentionally have invalid results in them. To do validation in this scenario, use the -halo=3 flag to specify how large of a halo should be ignored in validation in each dimension.

Examples of program descriptions are located in test/stencils, including for 2D and 3D stencils, vectorization, and lower dimensional inputs.

All executables are included in the bin subfolder, and have documented command line interfaces.

The repository ships with a number of tests that verify various aspects of functionality. These can be run with:

test/test_stencil.py

It is a known issue that launching multiple Intel FPGA kernels in quick succession (such as is done in the tests) can sometimes fail sporadically, seemingly due to file I/O issues. Running individual programs should never fail.