erff.sollya

// tables and constants for approximating erff(x).
//
// Copyright (c) 2023-2024, Arm Limited.
// SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception

display = hexadecimal;
prec=128;

// Tables
print("{ i, r, erf(r), 2/sqrt(pi) * exp(-r^2)}");
for i from 0 to 512 do {
  r = i / 128;
  t0 = single(erf(r));
  t1 = single(2/sqrt(pi) * exp(-r * r));
  print("{ " @ i @ ",\t" @ r @ ",\t" @ t0 @ ",\t" @ t1 @ " },");
};

// Constants
single(1/3);
single(2/sqrt(pi));