Home

YAFU Wiki

Yet Another Factoring Utility — an automated integer factorization tool.

YAFU combines modern factoring algorithms (trial division, Pollard rho, P-1, P+1, ECM, SIQS, GNFS, SNFS) into an adaptive pipeline that picks the right method for the input. It can be used as a one-shot command-line factorer or as an interactive environment (similar to PARI/GP or MATLAB) with its own expression language.

Contents

• Building YAFU — How to compile YAFU using the unified Makefile + config.mk system, on Linux, MSYS2/MinGW-w64, and Windows (MSVC).
• Continuous Integration — The GitHub Actions CI matrix, the released artifacts, and how to reproduce a CI build locally.
• Configuration and Command-Line Options — Every option that can be set on the command line or in yafu.ini, grouped by category.
• Functions Reference — Every callable function (factor, siqs, nfs, ecm, pm1, etc.), with usage, description, and the options that affect it.
• Expressions, Variables, and Reserved Words — The expression language used in interactive mode, scripts, and batchfiles.
• Pretesting Plans and T-Levels — How factor() decides how much ECM to do before NFS/SIQS, and what t-levels mean.
• Tips, Examples, and Troubleshooting — Common usage patterns, examples, and where to ask for help.
• Benchmarks — SIQS benchmarks over common input sizes.

Quick start

The easiest path is a pre-built Windows binary from the latest release — all builds are fully static, no DLLs required:

File	Best for
yafu-windows-generic.exe	Any x86-64 CPU — widest compatibility
yafu-windows-sse41.exe	Intel Core 2 / Penryn (2008) and newer
yafu-windows-avx2.exe	Haswell (2013) and newer — recommended for most users
yafu-windows-avx512.exe	Skylake-X / Cascade Lake / Zen 4 (AVX-512)
yafu-windows-avx512ifma.exe	Ice Lake and newer — best ECM performance

Run from a terminal:

# Factor an arbitrary integer
yafu "factor(2056802480868100646375721251575555494408897387375737955882170045672576386016591560879707933101909539325829251496440620798637813)"

# Or open the interactive prompt
yafu
>> factor(rsa(200))

For Linux, WSL, MSYS2/MinGW, or building from source on Windows, see Building YAFU.

Where things live

Item	Location
Source / releases	https://github.com/bbuhrow/yafu
Pre-built Windows binaries	https://github.com/bbuhrow/yafu/releases/latest
In-program help	type help or help <function> at the YAFU prompt
Config file	yafu.ini next to the binary
Per-machine build config	config.mk next to Makefile (copy from config.mk.example)
Community / support	mersenneforum.org node 58

Note on this wiki. The content here is derived from yafu.ini, docfile.txt, Makefile, config.mk.example, and the README in the repository. Those files remain the source of truth; if anything in this wiki disagrees with them, the repo files win.