xref: /aosp_15_r20/external/arm-optimized-routines/pl/math/tools/expm1.sollya (revision 412f47f9e737e10ed5cc46ec6a8d7fa2264f8a14)
1*412f47f9SXin Li// polynomial for approximating exp(x)-1 in double precision
2*412f47f9SXin Li//
3*412f47f9SXin Li// Copyright (c) 2022-2023, Arm Limited.
4*412f47f9SXin Li// SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
5*412f47f9SXin Li
6*412f47f9SXin Lideg = 12;
7*412f47f9SXin Li
8*412f47f9SXin Lia = -log(2)/2;
9*412f47f9SXin Lib = log(2)/2;
10*412f47f9SXin Li
11*412f47f9SXin Lif = proc(y) {
12*412f47f9SXin Li  return exp(y)-1;
13*412f47f9SXin Li};
14*412f47f9SXin Li
15*412f47f9SXin Lipoly = fpminimax(f(x), deg, [|double ...|], [a;b]);
16*412f47f9SXin Li
17*412f47f9SXin Lidisplay = hexadecimal;
18*412f47f9SXin Liprint("rel error:", accurateinfnorm(1-poly(x)/f(x), [a;b], 30));
19*412f47f9SXin Liprint("in [",a,b,"]");
20*412f47f9SXin Liprint("coeffs:");
21*412f47f9SXin Lifor i from 2 to deg do round(coeff(poly,i), D, RN);
22