Snap for 10447354 from 172d24a7ae67ee7bae413d5a8618f1b5edc002be to mainline-tethering-releaseaml_tet_341712060aml_tet_341610020aml_tet_341511010aml_tet_341411060aml_tet_341310230aml_tet_341112070aml_tet_341010040aml_tet_340913030android14-mainline-tethering-release

Change-Id: I3d1ba62dd3ec4f1f932ef5e2ce24308402f6b85d

1 files changed, 31 insertions, 0 deletions

diff --git a/pl/math/tools/erfcf.sollya b/pl/math/tools/erfcf.sollya
new file mode 100644
index 0000000..69c6836
--- /dev/null
+++ b/pl/math/tools/erfcf.sollya
@@ -0,0 +1,31 @@
+// polynomial for approximating erfc(x)*exp(x*x)
+//
+// Copyright (c) 2022-2023, Arm Limited.
+// SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+
+deg = 15; // poly degree
+
+// interval bounds
+a = 0x1.0p-26;
+b = 2;
+
+f = proc(y) {
+  return erfc(y) * exp(y*y);
+};
+
+approx = proc(poly, d) {
+  return remez(1 - poly(x)/f(x), deg-d, [a;b], x^d/f(x), 1e-10);
+};
+
+poly = 0;
+for i from 0 to deg do {
+  p = roundcoefficients(approx(poly,i), [|D ...|]);
+  poly = poly + x^i*coeff(p,0);
+  print(i);
+};
+
+display = hexadecimal;
+print("rel error:", accurateinfnorm(1-poly(x)/f(x), [a;b], 30));
+print("in [",a,b,"]");
+print("coeffs:");
+for i from 0 to deg do coeff(poly,i);