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authorAndroid Build Coastguard Worker <android-build-coastguard-worker@google.com>2023-07-07 05:07:20 +0000
committerAndroid Build Coastguard Worker <android-build-coastguard-worker@google.com>2023-07-07 05:07:20 +0000
commit70bf985bf12dfa02e9d634a433858320aa2f29dd (patch)
treeb6182e391304fb3a42c51d482dcf671f540f2363 /pl/math/tools/atanf.sollya
parenta57d1a3f7aaf52c6cc32e264be96a14ed1cec5a0 (diff)
parent172d24a7ae67ee7bae413d5a8618f1b5edc002be (diff)
downloadarm-optimized-routines-70bf985bf12dfa02e9d634a433858320aa2f29dd.tar.gz
Change-Id: I215e72558ed58a0414b9cabba3e9c567d0895c17
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+// polynomial for approximating atanf(x)
+//
+// Copyright (c) 2022-2023, Arm Limited.
+// SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+
+// Generate list of monomials:
+// Taylor series of atan is of the form x + ax^3 + bx^5 + cx^7 + ...
+// So generate a, b, c, ... such that we can approximate atan(x) by:
+// x + x^3 * (a + bx^2 + cx^4 + ...)
+
+deg = 7;
+
+a = 1.1754943508222875e-38;
+b = 1;
+
+poly = fpminimax((atan(sqrt(x))-sqrt(x))/x^(3/2), deg, [|single ...|], [a;b]);
+
+display = hexadecimal;
+print("coeffs:");
+for i from 0 to deg do coeff(poly,i);