accurpy 0.1.3

Ultra-accurate and fast double-double FM_new approximation with ≤1 ULP guarantees

accurpy

Ultra-accurate and fast double-double (≈106-bit) approximation for the “new FM” function, with:

• STRICT mode (≤ 1 ULP across a broad domain), mirroring a validated Python DD algorithm
• OPT mode (FMA + 1-step cbrt), validated ≤ 1 ULP against STRICT on a dense 120k grid

Install

pip install accurpy

Usage

import numpy as np
from accurpy import approx_FM_new

y_strict = approx_FM_new(10.0, skip_exp=False, mode="strict")
y_opt    = approx_FM_new(10.0, skip_exp=False, mode="opt")

x = np.geomspace(1e-12, 300.0, 1_000_000)
y = approx_FM_new(x, skip_exp=True, mode="opt")

Modes

• mode="strict" — full double-double path with exact operation order (≤ 1 ULP).
• mode="opt" — faster path (FMA-based DD; 1-step cbrt), validated ≤ 1 ULP vs STRICT.

If the extension is unavailable, accurpy falls back to Python DD (slow but ≥ STRICT accuracy).

License

MIT