56 lines
2.3 KiB
Plaintext
56 lines
2.3 KiB
Plaintext
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[/
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Copyright 2011 - 2020 John Maddock.
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Copyright 2013 - 2019 Paul A. Bristow.
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Copyright 2013 Christopher Kormanyos.
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt).
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]
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[section:complex128 complex128]
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`#include <boost/multiprecision/complex128.hpp>`
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namespace boost{ namespace multiprecision{
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class complex128_backend;
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typedef number<complex128_backend, et_off> complex128;
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}} // namespaces
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The `complex128` number type is a very thin wrapper around GCC's `__float128` or Intel's `_Quad` data types
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and provides a complex-number type that is a drop-in replacement for the native C++ floating-point types, but with
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a 113 bit mantissa, and compatible with FORTRAN's 128-bit QUAD real.
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All the usual standard library functions are available, performance should be equivalent
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to the underlying native types.
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As well as the usual conversions from arithmetic and string types, instances of `float128` are
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copy constructible and assignable from GCC's `__float128` and Intel's `_Quad` data types.
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Things you should know when using this type:
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* Default constructed `complex128`s have the value zero.
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* This backend supports rvalue-references and is move-aware, making instantiations of `number` on this backend move aware.
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* It is not possible to round-trip objects of this type to and from a string and get back
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exactly the same value when compiled with Intel's C++ compiler and using `_Quad` as the underlying type: this is a current limitation of
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our code. Round tripping when using `__float128` as the underlying type is possible (both for GCC and Intel).
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* Conversion from a string results in a `std::runtime_error` being thrown if the string can not be interpreted
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as a valid floating-point number.
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* Division by zero results in an infinity being produced.
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* When using the Intel compiler, the underlying type defaults to `__float128` if it's available and `_Quad` if not. You can override
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the default by defining either `BOOST_MP_USE_FLOAT128` or `BOOST_MP_USE_QUAD`.
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* When the underlying type is Intel's `_Quad` type, the code must be compiled with the compiler option `-Qoption,cpp,--extended_float_type`.
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[h5 complex128 example:]
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[complex128_eg]
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Which results in the output:
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[complex128_out]
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[endsect] [/section:complex128 complex128]
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