c4658abe60
Summary: Currently std::asinh and std::acosh use std::pow to compute x^2. This results in a significant error when computing e.g. asinh(i) or acosh(-1). This patch expresses x^2 directly via x.real() and x.imag(), like it is done in libstdc++/glibc, and adds tests that checks the accuracy. Reviewers: EricWF, mclow.lists Reviewed By: mclow.lists Subscribers: christof, cfe-commits Differential Revision: https://reviews.llvm.org/D41629 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@325510 91177308-0d34-0410-b5e6-96231b3b80d8
82 lines
2.2 KiB
C++
82 lines
2.2 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// <complex>
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// template<class T>
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// complex<T>
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// __sqr(const complex<T>& x);
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#include <complex>
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#include <cassert>
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template <class T>
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void
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test()
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{
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const T tolerance = std::is_same<T, float>::value ? 1.e-6 : 1.e-14;
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typedef std::complex<T> cplx;
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struct test_case
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{
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cplx value;
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cplx expected;
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};
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const test_case cases[] = {
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{cplx( 0, 0), cplx( 0, 0)},
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{cplx( 1, 0), cplx( 1, 0)},
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{cplx( 2, 0), cplx( 4, 0)},
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{cplx(-1, 0), cplx( 1, 0)},
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{cplx( 0, 1), cplx(-1, 0)},
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{cplx( 0, 2), cplx(-4, 0)},
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{cplx( 0, -1), cplx(-1, 0)},
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{cplx( 1, 1), cplx( 0, 2)},
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{cplx( 1, -1), cplx( 0, -2)},
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{cplx(-1, -1), cplx( 0, 2)},
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{cplx(0.5, 0), cplx(0.25, 0)},
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};
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const unsigned num_cases = sizeof(cases) / sizeof(test_case);
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for (unsigned i = 0; i < num_cases; ++i)
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{
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const test_case& test = cases[i];
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const std::complex<T> actual = std::__sqr(test.value);
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assert(std::abs(actual.real() - test.expected.real()) < tolerance);
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assert(std::abs(actual.imag() - test.expected.imag()) < tolerance);
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}
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const cplx nan1 = std::__sqr(cplx(NAN, 0));
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assert(std::isnan(nan1.real()));
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assert(std::isnan(nan1.imag()));
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const cplx nan2 = std::__sqr(cplx(0, NAN));
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assert(std::isnan(nan2.real()));
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assert(std::isnan(nan2.imag()));
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const cplx nan3 = std::__sqr(cplx(NAN, NAN));
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assert(std::isnan(nan3.real()));
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assert(std::isnan(nan3.imag()));
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const cplx inf1 = std::__sqr(cplx(INFINITY, 0));
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assert(std::isinf(inf1.real()));
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assert(inf1.real() > 0);
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const cplx inf2 = std::__sqr(cplx(0, INFINITY));
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assert(std::isinf(inf2.real()));
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assert(inf2.real() < 0);
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}
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int main()
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{
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test<float>();
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test<double>();
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test<long double>();
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}
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