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| </pre><pre class="rust"><code><span class="comment">// Copyright 2018 Developers of the Rand project.</span> |
| <span class="comment">//</span> |
| <span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span> |
| <span class="comment">// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span> |
| <span class="comment">// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your</span> |
| <span class="comment">// option. This file may not be copied, modified, or distributed</span> |
| <span class="comment">// except according to those terms.</span> |
| |
| <span class="doccomment">//! Low-level API for sampling indices</span> |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"alloc"</span>)]</span> <span class="kw">use</span> <span class="ident">core::slice</span>; |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"alloc"</span>)]</span> <span class="kw">use</span> <span class="ident">alloc::vec</span>::{<span class="self">self</span>, <span class="ident">Vec</span>}; |
| <span class="comment">// BTreeMap is not as fast in tests, but better than nothing.</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">all</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"alloc"</span>, <span class="ident">not</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)))]</span> |
| <span class="kw">use</span> <span class="ident">alloc::collections::BTreeSet</span>; |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> <span class="kw">use</span> <span class="ident">std::collections::HashSet</span>; |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::distributions::WeightedError</span>; |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"alloc"</span>)]</span> |
| <span class="kw">use</span> <span class="kw">crate</span>::{<span class="ident">Rng</span>, <span class="ident">distributions</span>::{<span class="ident">uniform::SampleUniform</span>, <span class="ident">Distribution</span>, <span class="ident">Uniform</span>}}; |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"serde1"</span>)]</span> |
| <span class="kw">use</span> <span class="ident">serde</span>::{<span class="ident">Serialize</span>, <span class="ident">Deserialize</span>}; |
| |
| <span class="doccomment">/// A vector of indices.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Multiple internal representations are possible.</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"serde1"</span>, <span class="ident">derive</span>(<span class="ident">Serialize</span>, <span class="ident">Deserialize</span>))]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">IndexVec</span> { |
| <span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span> |
| <span class="ident">U32</span>(<span class="ident">Vec</span><span class="op"><</span><span class="ident">u32</span><span class="op">></span>), |
| <span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span> |
| <span class="ident">USize</span>(<span class="ident">Vec</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>), |
| } |
| |
| <span class="kw">impl</span> <span class="ident">IndexVec</span> { |
| <span class="doccomment">/// Returns the number of indices</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">len</span>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="ident">usize</span> { |
| <span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> { |
| <span class="ident">IndexVec::U32</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">len</span>(), |
| <span class="ident">IndexVec::USize</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">len</span>(), |
| } |
| } |
| |
| <span class="doccomment">/// Returns `true` if the length is 0.</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="ident">bool</span> { |
| <span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> { |
| <span class="ident">IndexVec::U32</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">is_empty</span>(), |
| <span class="ident">IndexVec::USize</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">is_empty</span>(), |
| } |
| } |
| |
| <span class="doccomment">/// Return the value at the given `index`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// (Note: we cannot implement [`std::ops::Index`] because of lifetime</span> |
| <span class="doccomment">/// restrictions.)</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">index</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">index</span>: <span class="ident">usize</span>) -> <span class="ident">usize</span> { |
| <span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> { |
| <span class="ident">IndexVec::U32</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>[<span class="ident">index</span>] <span class="kw">as</span> <span class="ident">usize</span>, |
| <span class="ident">IndexVec::USize</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>[<span class="ident">index</span>], |
| } |
| } |
| |
| <span class="doccomment">/// Return result as a `Vec<usize>`. Conversion may or may not be trivial.</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_vec</span>(<span class="self">self</span>) -> <span class="ident">Vec</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { |
| <span class="kw">match</span> <span class="self">self</span> { |
| <span class="ident">IndexVec::U32</span>(<span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">into_iter</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">i</span><span class="op">|</span> <span class="ident">i</span> <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">collect</span>(), |
| <span class="ident">IndexVec::USize</span>(<span class="ident">v</span>) => <span class="ident">v</span>, |
| } |
| } |
| |
| <span class="doccomment">/// Iterate over the indices as a sequence of `usize` values</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">iter</span>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="ident">IndexVecIter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span> { |
| <span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> { |
| <span class="ident">IndexVec::U32</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">IndexVecIter::U32</span>(<span class="ident">v</span>.<span class="ident">iter</span>()), |
| <span class="ident">IndexVec::USize</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">IndexVecIter::USize</span>(<span class="ident">v</span>.<span class="ident">iter</span>()), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">IntoIterator</span> <span class="kw">for</span> <span class="ident">IndexVec</span> { |
| <span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">usize</span>; |
| <span class="kw">type</span> <span class="ident">IntoIter</span> <span class="op">=</span> <span class="ident">IndexVecIntoIter</span>; |
| |
| <span class="doccomment">/// Convert into an iterator over the indices as a sequence of `usize` values</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">into_iter</span>(<span class="self">self</span>) -> <span class="ident">IndexVecIntoIter</span> { |
| <span class="kw">match</span> <span class="self">self</span> { |
| <span class="ident">IndexVec::U32</span>(<span class="ident">v</span>) => <span class="ident">IndexVecIntoIter::U32</span>(<span class="ident">v</span>.<span class="ident">into_iter</span>()), |
| <span class="ident">IndexVec::USize</span>(<span class="ident">v</span>) => <span class="ident">IndexVecIntoIter::USize</span>(<span class="ident">v</span>.<span class="ident">into_iter</span>()), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">PartialEq</span> <span class="kw">for</span> <span class="ident">IndexVec</span> { |
| <span class="kw">fn</span> <span class="ident">eq</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">other</span>: <span class="kw-2">&</span><span class="ident">IndexVec</span>) -> <span class="ident">bool</span> { |
| <span class="kw">use</span> <span class="ident"><span class="self">self</span>::IndexVec</span>::<span class="kw-2">*</span>; |
| <span class="kw">match</span> (<span class="self">self</span>, <span class="ident">other</span>) { |
| (<span class="kw-2">&</span><span class="ident">U32</span>(<span class="kw-2">ref</span> <span class="ident">v1</span>), <span class="kw-2">&</span><span class="ident">U32</span>(<span class="kw-2">ref</span> <span class="ident">v2</span>)) => <span class="ident">v1</span> <span class="op">==</span> <span class="ident">v2</span>, |
| (<span class="kw-2">&</span><span class="ident">USize</span>(<span class="kw-2">ref</span> <span class="ident">v1</span>), <span class="kw-2">&</span><span class="ident">USize</span>(<span class="kw-2">ref</span> <span class="ident">v2</span>)) => <span class="ident">v1</span> <span class="op">==</span> <span class="ident">v2</span>, |
| (<span class="kw-2">&</span><span class="ident">U32</span>(<span class="kw-2">ref</span> <span class="ident">v1</span>), <span class="kw-2">&</span><span class="ident">USize</span>(<span class="kw-2">ref</span> <span class="ident">v2</span>)) => { |
| (<span class="ident">v1</span>.<span class="ident">len</span>() <span class="op">==</span> <span class="ident">v2</span>.<span class="ident">len</span>()) <span class="op">&&</span> (<span class="ident">v1</span>.<span class="ident">iter</span>().<span class="ident">zip</span>(<span class="ident">v2</span>.<span class="ident">iter</span>()).<span class="ident">all</span>(<span class="op">|</span>(<span class="ident">x</span>, <span class="ident">y</span>)<span class="op">|</span> <span class="kw-2">*</span><span class="ident">x</span> <span class="kw">as</span> <span class="ident">usize</span> <span class="op">==</span> <span class="kw-2">*</span><span class="ident">y</span>)) |
| } |
| (<span class="kw-2">&</span><span class="ident">USize</span>(<span class="kw-2">ref</span> <span class="ident">v1</span>), <span class="kw-2">&</span><span class="ident">U32</span>(<span class="kw-2">ref</span> <span class="ident">v2</span>)) => { |
| (<span class="ident">v1</span>.<span class="ident">len</span>() <span class="op">==</span> <span class="ident">v2</span>.<span class="ident">len</span>()) <span class="op">&&</span> (<span class="ident">v1</span>.<span class="ident">iter</span>().<span class="ident">zip</span>(<span class="ident">v2</span>.<span class="ident">iter</span>()).<span class="ident">all</span>(<span class="op">|</span>(<span class="ident">x</span>, <span class="ident">y</span>)<span class="op">|</span> <span class="kw-2">*</span><span class="ident">x</span> <span class="op">==</span> <span class="kw-2">*</span><span class="ident">y</span> <span class="kw">as</span> <span class="ident">usize</span>)) |
| } |
| } |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">From</span><span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="ident">u32</span><span class="op">></span><span class="op">></span> <span class="kw">for</span> <span class="ident">IndexVec</span> { |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">v</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">u32</span><span class="op">></span>) -> <span class="self">Self</span> { |
| <span class="ident">IndexVec::U32</span>(<span class="ident">v</span>) |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">From</span><span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span><span class="op">></span> <span class="kw">for</span> <span class="ident">IndexVec</span> { |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">v</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>) -> <span class="self">Self</span> { |
| <span class="ident">IndexVec::USize</span>(<span class="ident">v</span>) |
| } |
| } |
| |
| <span class="doccomment">/// Return type of `IndexVec::iter`.</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">IndexVecIter</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { |
| <span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span> |
| <span class="ident">U32</span>(<span class="ident">slice::Iter</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">u32</span><span class="op">></span>), |
| <span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span> |
| <span class="ident">USize</span>(<span class="ident">slice::Iter</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">usize</span><span class="op">></span>), |
| } |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">IndexVecIter</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { |
| <span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">usize</span>; |
| |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&mut</span> <span class="self">self</span>) -> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { |
| <span class="kw">use</span> <span class="ident"><span class="self">self</span>::IndexVecIter</span>::<span class="kw-2">*</span>; |
| <span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> { |
| <span class="ident">U32</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">iter</span>) => <span class="ident">iter</span>.<span class="ident">next</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">i</span><span class="op">|</span> <span class="kw-2">*</span><span class="ident">i</span> <span class="kw">as</span> <span class="ident">usize</span>), |
| <span class="ident">USize</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">iter</span>) => <span class="ident">iter</span>.<span class="ident">next</span>().<span class="ident">cloned</span>(), |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&</span><span class="self">self</span>) -> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>) { |
| <span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> { |
| <span class="ident">IndexVecIter::U32</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">size_hint</span>(), |
| <span class="ident">IndexVecIter::USize</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">size_hint</span>(), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">ExactSizeIterator</span> <span class="kw">for</span> <span class="ident">IndexVecIter</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> {} |
| |
| <span class="doccomment">/// Return type of `IndexVec::into_iter`.</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">IndexVecIntoIter</span> { |
| <span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span> |
| <span class="ident">U32</span>(<span class="ident">vec::IntoIter</span><span class="op"><</span><span class="ident">u32</span><span class="op">></span>), |
| <span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span> |
| <span class="ident">USize</span>(<span class="ident">vec::IntoIter</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>), |
| } |
| |
| <span class="kw">impl</span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">IndexVecIntoIter</span> { |
| <span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">usize</span>; |
| |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&mut</span> <span class="self">self</span>) -> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident"><span class="self">Self</span>::Item</span><span class="op">></span> { |
| <span class="kw">use</span> <span class="ident"><span class="self">self</span>::IndexVecIntoIter</span>::<span class="kw-2">*</span>; |
| <span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> { |
| <span class="ident">U32</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">next</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">i</span><span class="op">|</span> <span class="ident">i</span> <span class="kw">as</span> <span class="ident">usize</span>), |
| <span class="ident">USize</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">next</span>(), |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&</span><span class="self">self</span>) -> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>) { |
| <span class="kw">use</span> <span class="ident"><span class="self">self</span>::IndexVecIntoIter</span>::<span class="kw-2">*</span>; |
| <span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> { |
| <span class="ident">U32</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">size_hint</span>(), |
| <span class="ident">USize</span>(<span class="kw-2">ref</span> <span class="ident">v</span>) => <span class="ident">v</span>.<span class="ident">size_hint</span>(), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">ExactSizeIterator</span> <span class="kw">for</span> <span class="ident">IndexVecIntoIter</span> {} |
| |
| |
| <span class="doccomment">/// Randomly sample exactly `amount` distinct indices from `0..length`, and</span> |
| <span class="doccomment">/// return them in random order (fully shuffled).</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This method is used internally by the slice sampling methods, but it can</span> |
| <span class="doccomment">/// sometimes be useful to have the indices themselves so this is provided as</span> |
| <span class="doccomment">/// an alternative.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The implementation used is not specified; we automatically select the</span> |
| <span class="doccomment">/// fastest available algorithm for the `length` and `amount` parameters</span> |
| <span class="doccomment">/// (based on detailed profiling on an Intel Haswell CPU). Roughly speaking,</span> |
| <span class="doccomment">/// complexity is `O(amount)`, except that when `amount` is small, performance</span> |
| <span class="doccomment">/// is closer to `O(amount^2)`, and when `length` is close to `amount` then</span> |
| <span class="doccomment">/// `O(length)`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Note that performance is significantly better over `u32` indices than over</span> |
| <span class="doccomment">/// `u64` indices. Because of this we hide the underlying type behind an</span> |
| <span class="doccomment">/// abstraction, `IndexVec`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// If an allocation-free `no_std` function is required, it is suggested</span> |
| <span class="doccomment">/// to adapt the internal `sample_floyd` implementation.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Panics if `amount > length`.</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">sample</span><span class="op"><</span><span class="ident">R</span><span class="op">></span>(<span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>, <span class="ident">length</span>: <span class="ident">usize</span>, <span class="ident">amount</span>: <span class="ident">usize</span>) -> <span class="ident">IndexVec</span> |
| <span class="kw">where</span> <span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span> { |
| <span class="kw">if</span> <span class="ident">amount</span> <span class="op">></span> <span class="ident">length</span> { |
| <span class="macro">panic!</span>(<span class="string">"`amount` of samples must be less than or equal to `length`"</span>); |
| } |
| <span class="kw">if</span> <span class="ident">length</span> <span class="op">></span> (<span class="ident">::core::u32::MAX</span> <span class="kw">as</span> <span class="ident">usize</span>) { |
| <span class="comment">// We never want to use inplace here, but could use floyd's alg</span> |
| <span class="comment">// Lazy version: always use the cache alg.</span> |
| <span class="kw">return</span> <span class="ident">sample_rejection</span>(<span class="ident">rng</span>, <span class="ident">length</span>, <span class="ident">amount</span>); |
| } |
| <span class="kw">let</span> <span class="ident">amount</span> <span class="op">=</span> <span class="ident">amount</span> <span class="kw">as</span> <span class="ident">u32</span>; |
| <span class="kw">let</span> <span class="ident">length</span> <span class="op">=</span> <span class="ident">length</span> <span class="kw">as</span> <span class="ident">u32</span>; |
| |
| <span class="comment">// Choice of algorithm here depends on both length and amount. See:</span> |
| <span class="comment">// https://github.com/rust-random/rand/pull/479</span> |
| <span class="comment">// We do some calculations with f32. Accuracy is not very important.</span> |
| |
| <span class="kw">if</span> <span class="ident">amount</span> <span class="op"><</span> <span class="number">163</span> { |
| <span class="kw">const</span> <span class="ident">C</span>: [[<span class="ident">f32</span>; <span class="number">2</span>]; <span class="number">2</span>] <span class="op">=</span> [[<span class="number">1.6</span>, <span class="number">8.0</span> <span class="op">/</span> <span class="number">45.0</span>], [<span class="number">10.0</span>, <span class="number">70.0</span> <span class="op">/</span> <span class="number">9.0</span>]]; |
| <span class="kw">let</span> <span class="ident">j</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">length</span> <span class="op"><</span> <span class="number">500_000</span> { <span class="number">0</span> } <span class="kw">else</span> { <span class="number">1</span> }; |
| <span class="kw">let</span> <span class="ident">amount_fp</span> <span class="op">=</span> <span class="ident">amount</span> <span class="kw">as</span> <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="ident">m4</span> <span class="op">=</span> <span class="ident">C</span>[<span class="number">0</span>][<span class="ident">j</span>] <span class="op">*</span> <span class="ident">amount_fp</span>; |
| <span class="comment">// Short-cut: when amount < 12, floyd's is always faster</span> |
| <span class="kw">if</span> <span class="ident">amount</span> <span class="op">></span> <span class="number">11</span> <span class="op">&&</span> (<span class="ident">length</span> <span class="kw">as</span> <span class="ident">f32</span>) <span class="op"><</span> (<span class="ident">C</span>[<span class="number">1</span>][<span class="ident">j</span>] <span class="op">+</span> <span class="ident">m4</span>) <span class="op">*</span> <span class="ident">amount_fp</span> { |
| <span class="ident">sample_inplace</span>(<span class="ident">rng</span>, <span class="ident">length</span>, <span class="ident">amount</span>) |
| } <span class="kw">else</span> { |
| <span class="ident">sample_floyd</span>(<span class="ident">rng</span>, <span class="ident">length</span>, <span class="ident">amount</span>) |
| } |
| } <span class="kw">else</span> { |
| <span class="kw">const</span> <span class="ident">C</span>: [<span class="ident">f32</span>; <span class="number">2</span>] <span class="op">=</span> [<span class="number">270.0</span>, <span class="number">330.0</span> <span class="op">/</span> <span class="number">9.0</span>]; |
| <span class="kw">let</span> <span class="ident">j</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">length</span> <span class="op"><</span> <span class="number">500_000</span> { <span class="number">0</span> } <span class="kw">else</span> { <span class="number">1</span> }; |
| <span class="kw">if</span> (<span class="ident">length</span> <span class="kw">as</span> <span class="ident">f32</span>) <span class="op"><</span> <span class="ident">C</span>[<span class="ident">j</span>] <span class="op">*</span> (<span class="ident">amount</span> <span class="kw">as</span> <span class="ident">f32</span>) { |
| <span class="ident">sample_inplace</span>(<span class="ident">rng</span>, <span class="ident">length</span>, <span class="ident">amount</span>) |
| } <span class="kw">else</span> { |
| <span class="ident">sample_rejection</span>(<span class="ident">rng</span>, <span class="ident">length</span>, <span class="ident">amount</span>) |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Randomly sample exactly `amount` distinct indices from `0..length`, and</span> |
| <span class="doccomment">/// return them in an arbitrary order (there is no guarantee of shuffling or</span> |
| <span class="doccomment">/// ordering). The weights are to be provided by the input function `weights`,</span> |
| <span class="doccomment">/// which will be called once for each index.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This method is used internally by the slice sampling methods, but it can</span> |
| <span class="doccomment">/// sometimes be useful to have the indices themselves so this is provided as</span> |
| <span class="doccomment">/// an alternative.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This implementation uses `O(length + amount)` space and `O(length)` time</span> |
| <span class="doccomment">/// if the "nightly" feature is enabled, or `O(length)` space and</span> |
| <span class="doccomment">/// `O(length + amount * log length)` time otherwise.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Panics if `amount > length`.</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)))]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">sample_weighted</span><span class="op"><</span><span class="ident">R</span>, <span class="ident">F</span>, <span class="ident">X</span><span class="op">></span>( |
| <span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>, <span class="ident">length</span>: <span class="ident">usize</span>, <span class="ident">weight</span>: <span class="ident">F</span>, <span class="ident">amount</span>: <span class="ident">usize</span>, |
| ) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">IndexVec</span>, <span class="ident">WeightedError</span><span class="op">></span> |
| <span class="kw">where</span> |
| <span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span>, |
| <span class="ident">F</span>: <span class="ident">Fn</span>(<span class="ident">usize</span>) -> <span class="ident">X</span>, |
| <span class="ident">X</span>: <span class="ident">Into</span><span class="op"><</span><span class="ident">f64</span><span class="op">></span>, |
| { |
| <span class="kw">if</span> <span class="ident">length</span> <span class="op">></span> (<span class="ident">core::u32::MAX</span> <span class="kw">as</span> <span class="ident">usize</span>) { |
| <span class="ident">sample_efraimidis_spirakis</span>(<span class="ident">rng</span>, <span class="ident">length</span>, <span class="ident">weight</span>, <span class="ident">amount</span>) |
| } <span class="kw">else</span> { |
| <span class="macro">assert!</span>(<span class="ident">amount</span> <span class="op"><</span><span class="op">=</span> <span class="ident">core::u32::MAX</span> <span class="kw">as</span> <span class="ident">usize</span>); |
| <span class="kw">let</span> <span class="ident">amount</span> <span class="op">=</span> <span class="ident">amount</span> <span class="kw">as</span> <span class="ident">u32</span>; |
| <span class="kw">let</span> <span class="ident">length</span> <span class="op">=</span> <span class="ident">length</span> <span class="kw">as</span> <span class="ident">u32</span>; |
| <span class="ident">sample_efraimidis_spirakis</span>(<span class="ident">rng</span>, <span class="ident">length</span>, <span class="ident">weight</span>, <span class="ident">amount</span>) |
| } |
| } |
| |
| |
| <span class="doccomment">/// Randomly sample exactly `amount` distinct indices from `0..length`, and</span> |
| <span class="doccomment">/// return them in an arbitrary order (there is no guarantee of shuffling or</span> |
| <span class="doccomment">/// ordering). The weights are to be provided by the input function `weights`,</span> |
| <span class="doccomment">/// which will be called once for each index.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This implementation uses the algorithm described by Efraimidis and Spirakis</span> |
| <span class="doccomment">/// in this paper: https://doi.org/10.1016/j.ipl.2005.11.003</span> |
| <span class="doccomment">/// It uses `O(length + amount)` space and `O(length)` time if the</span> |
| <span class="doccomment">/// "nightly" feature is enabled, or `O(length)` space and `O(length</span> |
| <span class="doccomment">/// + amount * log length)` time otherwise.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Panics if `amount > length`.</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> |
| <span class="kw">fn</span> <span class="ident">sample_efraimidis_spirakis</span><span class="op"><</span><span class="ident">R</span>, <span class="ident">F</span>, <span class="ident">X</span>, <span class="ident">N</span><span class="op">></span>( |
| <span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>, <span class="ident">length</span>: <span class="ident">N</span>, <span class="ident">weight</span>: <span class="ident">F</span>, <span class="ident">amount</span>: <span class="ident">N</span>, |
| ) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">IndexVec</span>, <span class="ident">WeightedError</span><span class="op">></span> |
| <span class="kw">where</span> |
| <span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span>, |
| <span class="ident">F</span>: <span class="ident">Fn</span>(<span class="ident">usize</span>) -> <span class="ident">X</span>, |
| <span class="ident">X</span>: <span class="ident">Into</span><span class="op"><</span><span class="ident">f64</span><span class="op">></span>, |
| <span class="ident">N</span>: <span class="ident">UInt</span>, |
| <span class="ident">IndexVec</span>: <span class="ident">From</span><span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="ident">N</span><span class="op">></span><span class="op">></span>, |
| { |
| <span class="kw">if</span> <span class="ident">amount</span> <span class="op">==</span> <span class="ident">N::zero</span>() { |
| <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="ident">IndexVec::U32</span>(<span class="ident">Vec::new</span>())); |
| } |
| |
| <span class="kw">if</span> <span class="ident">amount</span> <span class="op">></span> <span class="ident">length</span> { |
| <span class="macro">panic!</span>(<span class="string">"`amount` of samples must be less than or equal to `length`"</span>); |
| } |
| |
| <span class="kw">struct</span> <span class="ident">Element</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> { |
| <span class="ident">index</span>: <span class="ident">N</span>, |
| <span class="ident">key</span>: <span class="ident">f64</span>, |
| } |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> <span class="ident">PartialOrd</span> <span class="kw">for</span> <span class="ident">Element</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> { |
| <span class="kw">fn</span> <span class="ident">partial_cmp</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">other</span>: <span class="kw-2">&</span><span class="self">Self</span>) -> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">core::cmp::Ordering</span><span class="op">></span> { |
| <span class="self">self</span>.<span class="ident">key</span>.<span class="ident">partial_cmp</span>(<span class="kw-2">&</span><span class="ident">other</span>.<span class="ident">key</span>) |
| } |
| } |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> <span class="ident">Ord</span> <span class="kw">for</span> <span class="ident">Element</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> { |
| <span class="kw">fn</span> <span class="ident">cmp</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">other</span>: <span class="kw-2">&</span><span class="self">Self</span>) -> <span class="ident">core::cmp::Ordering</span> { |
| <span class="comment">// partial_cmp will always produce a value,</span> |
| <span class="comment">// because we check that the weights are not nan</span> |
| <span class="self">self</span>.<span class="ident">partial_cmp</span>(<span class="ident">other</span>).<span class="ident">unwrap</span>() |
| } |
| } |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> <span class="ident">PartialEq</span> <span class="kw">for</span> <span class="ident">Element</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> { |
| <span class="kw">fn</span> <span class="ident">eq</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">other</span>: <span class="kw-2">&</span><span class="self">Self</span>) -> <span class="ident">bool</span> { |
| <span class="self">self</span>.<span class="ident">key</span> <span class="op">==</span> <span class="ident">other</span>.<span class="ident">key</span> |
| } |
| } |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> <span class="ident">Eq</span> <span class="kw">for</span> <span class="ident">Element</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> {} |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"nightly"</span>)]</span> |
| { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">candidates</span> <span class="op">=</span> <span class="ident">Vec::with_capacity</span>(<span class="ident">length</span>.<span class="ident">as_usize</span>()); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">index</span> <span class="op">=</span> <span class="ident">N::zero</span>(); |
| <span class="kw">while</span> <span class="ident">index</span> <span class="op"><</span> <span class="ident">length</span> { |
| <span class="kw">let</span> <span class="ident">weight</span> <span class="op">=</span> <span class="ident">weight</span>(<span class="ident">index</span>.<span class="ident">as_usize</span>()).<span class="ident">into</span>(); |
| <span class="kw">if</span> <span class="op">!</span>(<span class="ident">weight</span> <span class="op">></span><span class="op">=</span> <span class="number">0.</span>) { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">WeightedError::InvalidWeight</span>); |
| } |
| |
| <span class="kw">let</span> <span class="ident">key</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">gen</span>::<span class="op"><</span><span class="ident">f64</span><span class="op">></span>().<span class="ident">powf</span>(<span class="number">1.0</span> <span class="op">/</span> <span class="ident">weight</span>); |
| <span class="ident">candidates</span>.<span class="ident">push</span>(<span class="ident">Element</span> { <span class="ident">index</span>, <span class="ident">key</span> }); |
| |
| <span class="ident">index</span> <span class="op">+</span><span class="op">=</span> <span class="ident">N::one</span>(); |
| } |
| |
| <span class="comment">// Partially sort the array to find the `amount` elements with the greatest</span> |
| <span class="comment">// keys. Do this by using `select_nth_unstable` to put the elements with</span> |
| <span class="comment">// the *smallest* keys at the beginning of the list in `O(n)` time, which</span> |
| <span class="comment">// provides equivalent information about the elements with the *greatest* keys.</span> |
| <span class="kw">let</span> (<span class="kw">_</span>, <span class="ident">mid</span>, <span class="ident">greater</span>) |
| <span class="op">=</span> <span class="ident">candidates</span>.<span class="ident">select_nth_unstable</span>(<span class="ident">length</span>.<span class="ident">as_usize</span>() <span class="op">-</span> <span class="ident">amount</span>.<span class="ident">as_usize</span>()); |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">result</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> <span class="op">=</span> <span class="ident">Vec::with_capacity</span>(<span class="ident">amount</span>.<span class="ident">as_usize</span>()); |
| <span class="ident">result</span>.<span class="ident">push</span>(<span class="ident">mid</span>.<span class="ident">index</span>); |
| <span class="kw">for</span> <span class="ident">element</span> <span class="kw">in</span> <span class="ident">greater</span> { |
| <span class="ident">result</span>.<span class="ident">push</span>(<span class="ident">element</span>.<span class="ident">index</span>); |
| } |
| <span class="prelude-val">Ok</span>(<span class="ident">IndexVec::from</span>(<span class="ident">result</span>)) |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"nightly"</span>))]</span> |
| { |
| <span class="kw">use</span> <span class="ident">alloc::collections::BinaryHeap</span>; |
| |
| <span class="comment">// Partially sort the array such that the `amount` elements with the largest</span> |
| <span class="comment">// keys are first using a binary max heap.</span> |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">candidates</span> <span class="op">=</span> <span class="ident">BinaryHeap::with_capacity</span>(<span class="ident">length</span>.<span class="ident">as_usize</span>()); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">index</span> <span class="op">=</span> <span class="ident">N::zero</span>(); |
| <span class="kw">while</span> <span class="ident">index</span> <span class="op"><</span> <span class="ident">length</span> { |
| <span class="kw">let</span> <span class="ident">weight</span> <span class="op">=</span> <span class="ident">weight</span>(<span class="ident">index</span>.<span class="ident">as_usize</span>()).<span class="ident">into</span>(); |
| <span class="kw">if</span> <span class="op">!</span>(<span class="ident">weight</span> <span class="op">></span><span class="op">=</span> <span class="number">0.</span>) { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">WeightedError::InvalidWeight</span>); |
| } |
| |
| <span class="kw">let</span> <span class="ident">key</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">gen</span>::<span class="op"><</span><span class="ident">f64</span><span class="op">></span>().<span class="ident">powf</span>(<span class="number">1.0</span> <span class="op">/</span> <span class="ident">weight</span>); |
| <span class="ident">candidates</span>.<span class="ident">push</span>(<span class="ident">Element</span> { <span class="ident">index</span>, <span class="ident">key</span> }); |
| |
| <span class="ident">index</span> <span class="op">+</span><span class="op">=</span> <span class="ident">N::one</span>(); |
| } |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">result</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">N</span><span class="op">></span> <span class="op">=</span> <span class="ident">Vec::with_capacity</span>(<span class="ident">amount</span>.<span class="ident">as_usize</span>()); |
| <span class="kw">while</span> <span class="ident">result</span>.<span class="ident">len</span>() <span class="op"><</span> <span class="ident">amount</span>.<span class="ident">as_usize</span>() { |
| <span class="ident">result</span>.<span class="ident">push</span>(<span class="ident">candidates</span>.<span class="ident">pop</span>().<span class="ident">unwrap</span>().<span class="ident">index</span>); |
| } |
| <span class="prelude-val">Ok</span>(<span class="ident">IndexVec::from</span>(<span class="ident">result</span>)) |
| } |
| } |
| |
| <span class="doccomment">/// Randomly sample exactly `amount` indices from `0..length`, using Floyd's</span> |
| <span class="doccomment">/// combination algorithm.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The output values are fully shuffled. (Overhead is under 50%.)</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This implementation uses `O(amount)` memory and `O(amount^2)` time.</span> |
| <span class="kw">fn</span> <span class="ident">sample_floyd</span><span class="op"><</span><span class="ident">R</span><span class="op">></span>(<span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>, <span class="ident">length</span>: <span class="ident">u32</span>, <span class="ident">amount</span>: <span class="ident">u32</span>) -> <span class="ident">IndexVec</span> |
| <span class="kw">where</span> <span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span> { |
| <span class="comment">// For small amount we use Floyd's fully-shuffled variant. For larger</span> |
| <span class="comment">// amounts this is slow due to Vec::insert performance, so we shuffle</span> |
| <span class="comment">// afterwards. Benchmarks show little overhead from extra logic.</span> |
| <span class="kw">let</span> <span class="ident">floyd_shuffle</span> <span class="op">=</span> <span class="ident">amount</span> <span class="op"><</span> <span class="number">50</span>; |
| |
| <span class="macro">debug_assert!</span>(<span class="ident">amount</span> <span class="op"><</span><span class="op">=</span> <span class="ident">length</span>); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">indices</span> <span class="op">=</span> <span class="ident">Vec::with_capacity</span>(<span class="ident">amount</span> <span class="kw">as</span> <span class="ident">usize</span>); |
| <span class="kw">for</span> <span class="ident">j</span> <span class="kw">in</span> <span class="ident">length</span> <span class="op">-</span> <span class="ident">amount</span>..<span class="ident">length</span> { |
| <span class="kw">let</span> <span class="ident">t</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">gen_range</span>(<span class="number">0</span>..<span class="op">=</span><span class="ident">j</span>); |
| <span class="kw">if</span> <span class="ident">floyd_shuffle</span> { |
| <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">pos</span>) <span class="op">=</span> <span class="ident">indices</span>.<span class="ident">iter</span>().<span class="ident">position</span>(<span class="op">|</span><span class="kw-2">&</span><span class="ident">x</span><span class="op">|</span> <span class="ident">x</span> <span class="op">==</span> <span class="ident">t</span>) { |
| <span class="ident">indices</span>.<span class="ident">insert</span>(<span class="ident">pos</span>, <span class="ident">j</span>); |
| <span class="kw">continue</span>; |
| } |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">indices</span>.<span class="ident">contains</span>(<span class="kw-2">&</span><span class="ident">t</span>) { |
| <span class="ident">indices</span>.<span class="ident">push</span>(<span class="ident">j</span>); |
| <span class="kw">continue</span>; |
| } |
| <span class="ident">indices</span>.<span class="ident">push</span>(<span class="ident">t</span>); |
| } |
| <span class="kw">if</span> <span class="op">!</span><span class="ident">floyd_shuffle</span> { |
| <span class="comment">// Reimplement SliceRandom::shuffle with smaller indices</span> |
| <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> (<span class="number">1</span>..<span class="ident">amount</span>).<span class="ident">rev</span>() { |
| <span class="comment">// invariant: elements with index > i have been locked in place.</span> |
| <span class="ident">indices</span>.<span class="ident">swap</span>(<span class="ident">i</span> <span class="kw">as</span> <span class="ident">usize</span>, <span class="ident">rng</span>.<span class="ident">gen_range</span>(<span class="number">0</span>..<span class="op">=</span><span class="ident">i</span>) <span class="kw">as</span> <span class="ident">usize</span>); |
| } |
| } |
| <span class="ident">IndexVec::from</span>(<span class="ident">indices</span>) |
| } |
| |
| <span class="doccomment">/// Randomly sample exactly `amount` indices from `0..length`, using an inplace</span> |
| <span class="doccomment">/// partial Fisher-Yates method.</span> |
| <span class="doccomment">/// Sample an amount of indices using an inplace partial fisher yates method.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This allocates the entire `length` of indices and randomizes only the first `amount`.</span> |
| <span class="doccomment">/// It then truncates to `amount` and returns.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This method is not appropriate for large `length` and potentially uses a lot</span> |
| <span class="doccomment">/// of memory; because of this we only implement for `u32` index (which improves</span> |
| <span class="doccomment">/// performance in all cases).</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Set-up is `O(length)` time and memory and shuffling is `O(amount)` time.</span> |
| <span class="kw">fn</span> <span class="ident">sample_inplace</span><span class="op"><</span><span class="ident">R</span><span class="op">></span>(<span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>, <span class="ident">length</span>: <span class="ident">u32</span>, <span class="ident">amount</span>: <span class="ident">u32</span>) -> <span class="ident">IndexVec</span> |
| <span class="kw">where</span> <span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span> { |
| <span class="macro">debug_assert!</span>(<span class="ident">amount</span> <span class="op"><</span><span class="op">=</span> <span class="ident">length</span>); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">indices</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">u32</span><span class="op">></span> <span class="op">=</span> <span class="ident">Vec::with_capacity</span>(<span class="ident">length</span> <span class="kw">as</span> <span class="ident">usize</span>); |
| <span class="ident">indices</span>.<span class="ident">extend</span>(<span class="number">0</span>..<span class="ident">length</span>); |
| <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">amount</span> { |
| <span class="kw">let</span> <span class="ident">j</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">gen_range</span>(<span class="ident">i</span>..<span class="ident">length</span>); |
| <span class="ident">indices</span>.<span class="ident">swap</span>(<span class="ident">i</span> <span class="kw">as</span> <span class="ident">usize</span>, <span class="ident">j</span> <span class="kw">as</span> <span class="ident">usize</span>); |
| } |
| <span class="ident">indices</span>.<span class="ident">truncate</span>(<span class="ident">amount</span> <span class="kw">as</span> <span class="ident">usize</span>); |
| <span class="macro">debug_assert_eq!</span>(<span class="ident">indices</span>.<span class="ident">len</span>(), <span class="ident">amount</span> <span class="kw">as</span> <span class="ident">usize</span>); |
| <span class="ident">IndexVec::from</span>(<span class="ident">indices</span>) |
| } |
| |
| <span class="kw">trait</span> <span class="ident">UInt</span>: <span class="ident">Copy</span> <span class="op">+</span> <span class="ident">PartialOrd</span> <span class="op">+</span> <span class="ident">Ord</span> <span class="op">+</span> <span class="ident">PartialEq</span> <span class="op">+</span> <span class="ident">Eq</span> <span class="op">+</span> <span class="ident">SampleUniform</span> |
| <span class="op">+</span> <span class="ident">core::hash::Hash</span> <span class="op">+</span> <span class="ident">core::ops::AddAssign</span> { |
| <span class="kw">fn</span> <span class="ident">zero</span>() -> <span class="self">Self</span>; |
| <span class="kw">fn</span> <span class="ident">one</span>() -> <span class="self">Self</span>; |
| <span class="kw">fn</span> <span class="ident">as_usize</span>(<span class="self">self</span>) -> <span class="ident">usize</span>; |
| } |
| <span class="kw">impl</span> <span class="ident">UInt</span> <span class="kw">for</span> <span class="ident">u32</span> { |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zero</span>() -> <span class="self">Self</span> { |
| <span class="number">0</span> |
| } |
| |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">one</span>() -> <span class="self">Self</span> { |
| <span class="number">1</span> |
| } |
| |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">as_usize</span>(<span class="self">self</span>) -> <span class="ident">usize</span> { |
| <span class="self">self</span> <span class="kw">as</span> <span class="ident">usize</span> |
| } |
| } |
| <span class="kw">impl</span> <span class="ident">UInt</span> <span class="kw">for</span> <span class="ident">usize</span> { |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zero</span>() -> <span class="self">Self</span> { |
| <span class="number">0</span> |
| } |
| |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">one</span>() -> <span class="self">Self</span> { |
| <span class="number">1</span> |
| } |
| |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">as_usize</span>(<span class="self">self</span>) -> <span class="ident">usize</span> { |
| <span class="self">self</span> |
| } |
| } |
| |
| <span class="doccomment">/// Randomly sample exactly `amount` indices from `0..length`, using rejection</span> |
| <span class="doccomment">/// sampling.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Since `amount <<< length` there is a low chance of a random sample in</span> |
| <span class="doccomment">/// `0..length` being a duplicate. We test for duplicates and resample where</span> |
| <span class="doccomment">/// necessary. The algorithm is `O(amount)` time and memory.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This function is generic over X primarily so that results are value-stable</span> |
| <span class="doccomment">/// over 32-bit and 64-bit platforms.</span> |
| <span class="kw">fn</span> <span class="ident">sample_rejection</span><span class="op"><</span><span class="ident">X</span>: <span class="ident">UInt</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>, <span class="ident">length</span>: <span class="ident">X</span>, <span class="ident">amount</span>: <span class="ident">X</span>) -> <span class="ident">IndexVec</span> |
| <span class="kw">where</span> |
| <span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span>, |
| <span class="ident">IndexVec</span>: <span class="ident">From</span><span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="ident">X</span><span class="op">></span><span class="op">></span>, |
| { |
| <span class="macro">debug_assert!</span>(<span class="ident">amount</span> <span class="op"><</span> <span class="ident">length</span>); |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">cache</span> <span class="op">=</span> <span class="ident">HashSet::with_capacity</span>(<span class="ident">amount</span>.<span class="ident">as_usize</span>()); |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>))]</span> |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">cache</span> <span class="op">=</span> <span class="ident">BTreeSet::new</span>(); |
| <span class="kw">let</span> <span class="ident">distr</span> <span class="op">=</span> <span class="ident">Uniform::new</span>(<span class="ident">X::zero</span>(), <span class="ident">length</span>); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">indices</span> <span class="op">=</span> <span class="ident">Vec::with_capacity</span>(<span class="ident">amount</span>.<span class="ident">as_usize</span>()); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">amount</span>.<span class="ident">as_usize</span>() { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">pos</span> <span class="op">=</span> <span class="ident">distr</span>.<span class="ident">sample</span>(<span class="ident">rng</span>); |
| <span class="kw">while</span> <span class="op">!</span><span class="ident">cache</span>.<span class="ident">insert</span>(<span class="ident">pos</span>) { |
| <span class="ident">pos</span> <span class="op">=</span> <span class="ident">distr</span>.<span class="ident">sample</span>(<span class="ident">rng</span>); |
| } |
| <span class="ident">indices</span>.<span class="ident">push</span>(<span class="ident">pos</span>); |
| } |
| |
| <span class="macro">debug_assert_eq!</span>(<span class="ident">indices</span>.<span class="ident">len</span>(), <span class="ident">amount</span>.<span class="ident">as_usize</span>()); |
| <span class="ident">IndexVec::from</span>(<span class="ident">indices</span>) |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span> |
| <span class="kw">mod</span> <span class="ident">test</span> { |
| <span class="kw">use</span> <span class="kw">super</span>::<span class="kw-2">*</span>; |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"serde1"</span>)]</span> |
| <span class="kw">fn</span> <span class="ident">test_serialization_index_vec</span>() { |
| <span class="kw">let</span> <span class="ident">some_index_vec</span> <span class="op">=</span> <span class="ident">IndexVec::from</span>(<span class="macro">vec!</span>[<span class="number">254_usize</span>, <span class="number">234</span>, <span class="number">2</span>, <span class="number">1</span>]); |
| <span class="kw">let</span> <span class="ident">de_some_index_vec</span>: <span class="ident">IndexVec</span> <span class="op">=</span> <span class="ident">bincode::deserialize</span>(<span class="kw-2">&</span><span class="ident">bincode::serialize</span>(<span class="kw-2">&</span><span class="ident">some_index_vec</span>).<span class="ident">unwrap</span>()).<span class="ident">unwrap</span>(); |
| <span class="kw">match</span> (<span class="ident">some_index_vec</span>, <span class="ident">de_some_index_vec</span>) { |
| (<span class="ident">IndexVec::U32</span>(<span class="ident">a</span>), <span class="ident">IndexVec::U32</span>(<span class="ident">b</span>)) => { |
| <span class="macro">assert_eq!</span>(<span class="ident">a</span>, <span class="ident">b</span>); |
| }, |
| (<span class="ident">IndexVec::USize</span>(<span class="ident">a</span>), <span class="ident">IndexVec::USize</span>(<span class="ident">b</span>)) => { |
| <span class="macro">assert_eq!</span>(<span class="ident">a</span>, <span class="ident">b</span>); |
| }, |
| <span class="kw">_</span> => {<span class="macro">panic!</span>(<span class="string">"failed to seralize/deserialize `IndexVec`"</span>)} |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"alloc"</span>)]</span> <span class="kw">use</span> <span class="ident">alloc::vec</span>; |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">test_sample_boundaries</span>() { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">404</span>); |
| |
| <span class="macro">assert_eq!</span>(<span class="ident">sample_inplace</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">0</span>, <span class="number">0</span>).<span class="ident">len</span>(), <span class="number">0</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">sample_inplace</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">1</span>, <span class="number">0</span>).<span class="ident">len</span>(), <span class="number">0</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">sample_inplace</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">1</span>, <span class="number">1</span>).<span class="ident">into_vec</span>(), <span class="macro">vec!</span>[<span class="number">0</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="ident">sample_rejection</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">1u32</span>, <span class="number">0</span>).<span class="ident">len</span>(), <span class="number">0</span>); |
| |
| <span class="macro">assert_eq!</span>(<span class="ident">sample_floyd</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">0</span>, <span class="number">0</span>).<span class="ident">len</span>(), <span class="number">0</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">sample_floyd</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">1</span>, <span class="number">0</span>).<span class="ident">len</span>(), <span class="number">0</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">sample_floyd</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">1</span>, <span class="number">1</span>).<span class="ident">into_vec</span>(), <span class="macro">vec!</span>[<span class="number">0</span>]); |
| |
| <span class="comment">// These algorithms should be fast with big numbers. Test average.</span> |
| <span class="kw">let</span> <span class="ident">sum</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="ident">sample_rejection</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">25</span>, <span class="number">10u32</span>).<span class="ident">into_iter</span>().<span class="ident">sum</span>(); |
| <span class="macro">assert!</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">25</span> <span class="op"><</span> <span class="ident">sum</span> <span class="op">&&</span> <span class="ident">sum</span> <span class="op"><</span> (<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">25</span>) <span class="op">*</span> <span class="number">25</span>); |
| |
| <span class="kw">let</span> <span class="ident">sum</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="ident">sample_floyd</span>(<span class="kw-2">&mut</span> <span class="ident">r</span>, <span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">25</span>, <span class="number">10</span>).<span class="ident">into_iter</span>().<span class="ident">sum</span>(); |
| <span class="macro">assert!</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">25</span> <span class="op"><</span> <span class="ident">sum</span> <span class="op">&&</span> <span class="ident">sum</span> <span class="op"><</span> (<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">25</span>) <span class="op">*</span> <span class="number">25</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">miri</span>, <span class="ident">ignore</span>)]</span> <span class="comment">// Miri is too slow</span> |
| <span class="kw">fn</span> <span class="ident">test_sample_alg</span>() { |
| <span class="kw">let</span> <span class="ident">seed_rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>; |
| |
| <span class="comment">// We can't test which algorithm is used directly, but Floyd's alg</span> |
| <span class="comment">// should produce different results from the others. (Also, `inplace`</span> |
| <span class="comment">// and `cached` currently use different sizes thus produce different results.)</span> |
| |
| <span class="comment">// A small length and relatively large amount should use inplace</span> |
| <span class="kw">let</span> (<span class="ident">length</span>, <span class="ident">amount</span>): (<span class="ident">usize</span>, <span class="ident">usize</span>) <span class="op">=</span> (<span class="number">100</span>, <span class="number">50</span>); |
| <span class="kw">let</span> <span class="ident">v1</span> <span class="op">=</span> <span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">seed_rng</span>(<span class="number">420</span>), <span class="ident">length</span>, <span class="ident">amount</span>); |
| <span class="kw">let</span> <span class="ident">v2</span> <span class="op">=</span> <span class="ident">sample_inplace</span>(<span class="kw-2">&mut</span> <span class="ident">seed_rng</span>(<span class="number">420</span>), <span class="ident">length</span> <span class="kw">as</span> <span class="ident">u32</span>, <span class="ident">amount</span> <span class="kw">as</span> <span class="ident">u32</span>); |
| <span class="macro">assert!</span>(<span class="ident">v1</span>.<span class="ident">iter</span>().<span class="ident">all</span>(<span class="op">|</span><span class="ident">e</span><span class="op">|</span> <span class="ident">e</span> <span class="op"><</span> <span class="ident">length</span>)); |
| <span class="macro">assert_eq!</span>(<span class="ident">v1</span>, <span class="ident">v2</span>); |
| |
| <span class="comment">// Test Floyd's alg does produce different results</span> |
| <span class="kw">let</span> <span class="ident">v3</span> <span class="op">=</span> <span class="ident">sample_floyd</span>(<span class="kw-2">&mut</span> <span class="ident">seed_rng</span>(<span class="number">420</span>), <span class="ident">length</span> <span class="kw">as</span> <span class="ident">u32</span>, <span class="ident">amount</span> <span class="kw">as</span> <span class="ident">u32</span>); |
| <span class="macro">assert!</span>(<span class="ident">v1</span> <span class="op">!</span><span class="op">=</span> <span class="ident">v3</span>); |
| |
| <span class="comment">// A large length and small amount should use Floyd</span> |
| <span class="kw">let</span> (<span class="ident">length</span>, <span class="ident">amount</span>): (<span class="ident">usize</span>, <span class="ident">usize</span>) <span class="op">=</span> (<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">20</span>, <span class="number">50</span>); |
| <span class="kw">let</span> <span class="ident">v1</span> <span class="op">=</span> <span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">seed_rng</span>(<span class="number">421</span>), <span class="ident">length</span>, <span class="ident">amount</span>); |
| <span class="kw">let</span> <span class="ident">v2</span> <span class="op">=</span> <span class="ident">sample_floyd</span>(<span class="kw-2">&mut</span> <span class="ident">seed_rng</span>(<span class="number">421</span>), <span class="ident">length</span> <span class="kw">as</span> <span class="ident">u32</span>, <span class="ident">amount</span> <span class="kw">as</span> <span class="ident">u32</span>); |
| <span class="macro">assert!</span>(<span class="ident">v1</span>.<span class="ident">iter</span>().<span class="ident">all</span>(<span class="op">|</span><span class="ident">e</span><span class="op">|</span> <span class="ident">e</span> <span class="op"><</span> <span class="ident">length</span>)); |
| <span class="macro">assert_eq!</span>(<span class="ident">v1</span>, <span class="ident">v2</span>); |
| |
| <span class="comment">// A large length and larger amount should use cache</span> |
| <span class="kw">let</span> (<span class="ident">length</span>, <span class="ident">amount</span>): (<span class="ident">usize</span>, <span class="ident">usize</span>) <span class="op">=</span> (<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">20</span>, <span class="number">600</span>); |
| <span class="kw">let</span> <span class="ident">v1</span> <span class="op">=</span> <span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">seed_rng</span>(<span class="number">422</span>), <span class="ident">length</span>, <span class="ident">amount</span>); |
| <span class="kw">let</span> <span class="ident">v2</span> <span class="op">=</span> <span class="ident">sample_rejection</span>(<span class="kw-2">&mut</span> <span class="ident">seed_rng</span>(<span class="number">422</span>), <span class="ident">length</span> <span class="kw">as</span> <span class="ident">u32</span>, <span class="ident">amount</span> <span class="kw">as</span> <span class="ident">u32</span>); |
| <span class="macro">assert!</span>(<span class="ident">v1</span>.<span class="ident">iter</span>().<span class="ident">all</span>(<span class="op">|</span><span class="ident">e</span><span class="op">|</span> <span class="ident">e</span> <span class="op"><</span> <span class="ident">length</span>)); |
| <span class="macro">assert_eq!</span>(<span class="ident">v1</span>, <span class="ident">v2</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">test_sample_weighted</span>() { |
| <span class="kw">let</span> <span class="ident">seed_rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>; |
| <span class="kw">for</span> <span class="kw-2">&</span>(<span class="ident">amount</span>, <span class="ident">len</span>) <span class="kw">in</span> <span class="kw-2">&</span>[(<span class="number">0</span>, <span class="number">10</span>), (<span class="number">5</span>, <span class="number">10</span>), (<span class="number">10</span>, <span class="number">10</span>)] { |
| <span class="kw">let</span> <span class="ident">v</span> <span class="op">=</span> <span class="ident">sample_weighted</span>(<span class="kw-2">&mut</span> <span class="ident">seed_rng</span>(<span class="number">423</span>), <span class="ident">len</span>, <span class="op">|</span><span class="ident">i</span><span class="op">|</span> <span class="ident">i</span> <span class="kw">as</span> <span class="ident">f64</span>, <span class="ident">amount</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">match</span> <span class="ident">v</span> { |
| <span class="ident">IndexVec::U32</span>(<span class="kw-2">mut</span> <span class="ident">indices</span>) => { |
| <span class="macro">assert_eq!</span>(<span class="ident">indices</span>.<span class="ident">len</span>(), <span class="ident">amount</span>); |
| <span class="ident">indices</span>.<span class="ident">sort_unstable</span>(); |
| <span class="ident">indices</span>.<span class="ident">dedup</span>(); |
| <span class="macro">assert_eq!</span>(<span class="ident">indices</span>.<span class="ident">len</span>(), <span class="ident">amount</span>); |
| <span class="kw">for</span> <span class="kw-2">&</span><span class="ident">i</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">indices</span> { |
| <span class="macro">assert!</span>((<span class="ident">i</span> <span class="kw">as</span> <span class="ident">usize</span>) <span class="op"><</span> <span class="ident">len</span>); |
| } |
| }, |
| <span class="ident">IndexVec::USize</span>(<span class="kw">_</span>) => <span class="macro">panic!</span>(<span class="string">"expected `IndexVec::U32`"</span>), |
| } |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">value_stability_sample</span>() { |
| <span class="kw">let</span> <span class="ident">do_test</span> <span class="op">=</span> <span class="op">|</span><span class="ident">length</span>, <span class="ident">amount</span>, <span class="ident">values</span>: <span class="kw-2">&</span>[<span class="ident">u32</span>]<span class="op">|</span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="number">0u32</span>; <span class="number">8</span>]; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">410</span>); |
| |
| <span class="kw">let</span> <span class="ident">res</span> <span class="op">=</span> <span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>, <span class="ident">length</span>, <span class="ident">amount</span>); |
| <span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">res</span>.<span class="ident">len</span>().<span class="ident">min</span>(<span class="ident">buf</span>.<span class="ident">len</span>()); |
| <span class="kw">for</span> (<span class="ident">x</span>, <span class="ident">y</span>) <span class="kw">in</span> <span class="ident">res</span>.<span class="ident">into_iter</span>().<span class="ident">zip</span>(<span class="ident">buf</span>.<span class="ident">iter_mut</span>()) { |
| <span class="kw-2">*</span><span class="ident">y</span> <span class="op">=</span> <span class="ident">x</span> <span class="kw">as</span> <span class="ident">u32</span>; |
| } |
| <span class="macro">assert_eq!</span>( |
| <span class="kw-2">&</span><span class="ident">buf</span>[<span class="number">0</span>..<span class="ident">len</span>], |
| <span class="ident">values</span>, |
| <span class="string">"failed sampling {}, {}"</span>, |
| <span class="ident">length</span>, |
| <span class="ident">amount</span> |
| ); |
| }; |
| |
| <span class="ident">do_test</span>(<span class="number">10</span>, <span class="number">6</span>, <span class="kw-2">&</span>[<span class="number">8</span>, <span class="number">0</span>, <span class="number">3</span>, <span class="number">5</span>, <span class="number">9</span>, <span class="number">6</span>]); <span class="comment">// floyd</span> |
| <span class="ident">do_test</span>(<span class="number">25</span>, <span class="number">10</span>, <span class="kw-2">&</span>[<span class="number">18</span>, <span class="number">15</span>, <span class="number">14</span>, <span class="number">9</span>, <span class="number">0</span>, <span class="number">13</span>, <span class="number">5</span>, <span class="number">24</span>]); <span class="comment">// floyd</span> |
| <span class="ident">do_test</span>(<span class="number">300</span>, <span class="number">8</span>, <span class="kw-2">&</span>[<span class="number">30</span>, <span class="number">283</span>, <span class="number">150</span>, <span class="number">1</span>, <span class="number">73</span>, <span class="number">13</span>, <span class="number">285</span>, <span class="number">35</span>]); <span class="comment">// floyd</span> |
| <span class="ident">do_test</span>(<span class="number">300</span>, <span class="number">80</span>, <span class="kw-2">&</span>[<span class="number">31</span>, <span class="number">289</span>, <span class="number">248</span>, <span class="number">154</span>, <span class="number">5</span>, <span class="number">78</span>, <span class="number">19</span>, <span class="number">286</span>]); <span class="comment">// inplace</span> |
| <span class="ident">do_test</span>(<span class="number">300</span>, <span class="number">180</span>, <span class="kw-2">&</span>[<span class="number">31</span>, <span class="number">289</span>, <span class="number">248</span>, <span class="number">154</span>, <span class="number">5</span>, <span class="number">78</span>, <span class="number">19</span>, <span class="number">286</span>]); <span class="comment">// inplace</span> |
| |
| <span class="ident">do_test</span>(<span class="number">1_000_000</span>, <span class="number">8</span>, <span class="kw-2">&</span>[ |
| <span class="number">103717</span>, <span class="number">963485</span>, <span class="number">826422</span>, <span class="number">509101</span>, <span class="number">736394</span>, <span class="number">807035</span>, <span class="number">5327</span>, <span class="number">632573</span>, |
| ]); <span class="comment">// floyd</span> |
| <span class="ident">do_test</span>(<span class="number">1_000_000</span>, <span class="number">180</span>, <span class="kw-2">&</span>[ |
| <span class="number">103718</span>, <span class="number">963490</span>, <span class="number">826426</span>, <span class="number">509103</span>, <span class="number">736396</span>, <span class="number">807036</span>, <span class="number">5327</span>, <span class="number">632573</span>, |
| ]); <span class="comment">// rejection</span> |
| } |
| } |
| </code></pre></div> |
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