pl/math/tools/expm1.sollya

// polynomial for approximating exp(x)-1 in double precision
//
// Copyright (c) 2022-2023, Arm Limited.
// SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception

deg = 12;

a = -log(2)/2;
b = log(2)/2;

f = proc(y) {
  return exp(y)-1;
};

poly = fpminimax(f(x), deg, [|double ...|], [a;b]);

display = hexadecimal;
print("rel error:", accurateinfnorm(1-poly(x)/f(x), [a;b], 30));
print("in [",a,b,"]");
print("coeffs:");
for i from 2 to deg do round(coeff(poly,i), D, RN);