74 lines
6.5 KiB
HTML
74 lines
6.5 KiB
HTML
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<title>std::experimental::simd_cast, std::experimental::static_simd_cast</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::experimental::</span>simd_cast, <span style="font-size:0.7em; line-height:130%">std::experimental::</span>static_simd_cast</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-experimental.html">experimental</a>‎ | <a href="cpp-experimental-simd.html">simd</a></span></div>
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<div>定义于头文件 <code><a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/header/experimental/simd&action=edit&redlink=1" class="new" title="cpp/header/experimental/simd（页面不存在）"><experimental/simd></a></code></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1"><</span> <span class="kw1">class</span> V, <span class="kw1">class</span> T, <span class="kw1">class</span> Abi <span class="sy1">></span><br />
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<span class="coMULTI">/*see below*/</span> simd_cast<span class="br0">(</span> <span class="kw4">const</span> simd<span class="sy1"><</span>T, Abi<span class="sy1">></span><span class="sy3">&</span> v <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(1)</td>
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<td><span class="t-mark-rev t-since-parallelism-ts-2 t-mark-ts">(并行 TS v2)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1"><</span> <span class="kw1">class</span> V, <span class="kw1">class</span> T, <span class="kw1">class</span> Abi <span class="sy1">></span><br />
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<span class="coMULTI">/*see below*/</span> static_simd_cast<span class="br0">(</span> <span class="kw4">const</span> simd<span class="sy1"><</span>T, Abi<span class="sy1">></span><span class="sy3">&</span> v <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(2)</td>
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<td><span class="t-mark-rev t-since-parallelism-ts-2 t-mark-ts">(并行 TS v2)</span></td>
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<p>转型 simd 对象到另一 simd 对象。若 V 为 T ，则返回 <span class="t-c"><span class="mw-geshi cpp source-cpp">simd<span class="sy1"><</span>T, Abi<span class="sy1">></span></span></span> ；否则，若 V 为标量类型，则返回 <span class="t-c"><span class="mw-geshi cpp source-cpp">simd<span class="sy1"><</span>V, simd_abi<span class="sy4">::</span><span class="me2">fixed_size</span><span class="sy1"><</span>simd<span class="sy1"><</span>T, Abi<span class="sy1">></span><span class="sy4">::</span><span class="me2">size</span><span class="br0">(</span><span class="br0">)</span><span class="sy1">>></span></span></span> 。否则， V 必须是 simd 类型，而函数返回 V 。</p>
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<div class="t-li1"><span class="t-li">1)</span> 此函数不参与重载决议，除非
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<ul>
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<li>输入元素的每个可能值都能以输出元素表示</li>
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<li><span class="t-c"><span class="mw-geshi cpp source-cpp">is_simd_v<span class="sy1"><</span>V<span class="sy1">></span></span></span> 为 false 或 <span class="t-c"><span class="mw-geshi cpp source-cpp">V<span class="sy4">::</span><span class="me2">size</span><span class="br0">(</span><span class="br0">)</span></span></span> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp">simd<span class="sy1"><</span>T, Abi<span class="sy1">></span><span class="sy4">::</span><span class="me2">size</span><span class="br0">(</span><span class="br0">)</span></span></span></li>
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<div class="t-li1"><span class="t-li">2)</span> 此函数仅若 <span class="t-c"><span class="mw-geshi cpp source-cpp">is_simd_v<span class="sy1"><</span>V<span class="sy1">></span></span></span> 或 <span class="t-c"><span class="mw-geshi cpp source-cpp">V<span class="sy4">::</span><span class="me2">size</span><span class="br0">(</span><span class="br0">)</span></span></span> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp">simd<span class="sy1"><</span>T, Abi<span class="sy1">></span><span class="sy4">::</span><span class="me2">size</span><span class="br0">(</span><span class="br0">)</span></span></span> 才参与重载决议。</div>
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<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
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<td>v</td>
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<td>-</td>
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<td>输入的 simd 对象</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
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<p>第 i 元素初始化为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">static_cast</span><span class="sy1"><</span>To<span class="sy1">></span><span class="br0">(</span>v<span class="br0">[</span>i<span class="br0">]</span><span class="br0">)</span></span></span> 的 simd 对象，其中 To 是指定的输出元素类型。</p>
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<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
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