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

display = hexadecimal;
prec=128;

// Tables
print("{ i, r, erfc(r), 2/sqrt(pi) * exp(-r^2) }");
for i from 0 to 3787 do {
  r = 0.0 + i / 128;
  t0 = double(erfc(r) * 2^128);
  t1 = double(2/sqrt(pi) * exp(-r * r) * 2^128);
  print("{ " @ t0 @ ",\t" @ t1 @ " },");
};

// Constants
print("> 2/sqrt(pi)");
double(2/sqrt(pi));

print("> 1/3");
double(1/3);

print("> P5");
double(2/15);
double(1/10);
double(2/9);
double(2/45);

print("> P6");
double(1/42);
double(1/7);
double(2/21);
double(4/315);

print("> Q");
double( 5.0 / 4.0);
double( 6.0 / 5.0);
double( 7.0 / 6.0);
double( 8.0 / 7.0);
double( 9.0 / 8.0);
double(10.0 / 9.0);

print("> R");
double(-2.0 * 4.0 / (5.0 * 6.0));
double(-2.0 * 5.0 / (6.0 * 7.0));
double(-2.0 * 6.0 / (7.0 * 8.0));
double(-2.0 * 7.0 / (8.0 * 9.0));
double(-2.0 * 8.0 / (9.0 * 10.0));
double(-2.0 * 9.0 / (10.0 * 11.0));