<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Array zip macro: lock step function application across several arrays and producers."><meta name="keywords" content="rust, rustlang, rust-lang, azip"><title>azip in ndarray - Rust</title><link rel="stylesheet" type="text/css" href="../normalize.css"><link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../light.css" id="themeStyle"><link rel="stylesheet" type="text/css" href="../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../ayu.css" disabled ><script id="default-settings"></script><script src="../storage.js"></script><script src="../crates.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="icon" type="image/svg+xml" href="../favicon.svg">
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<span class="macro">macro_rules!</span> <span class="ident">azip</span> {
(@<span class="ident">parse</span> [<span class="ident">index</span> <span class="op">=</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>:<span class="ident">expr</span>, $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">aa</span>:<span class="ident">expr</span>,)<span class="kw-2">*</span>] <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t1</span>:<span class="ident">tt</span> <span class="kw">in</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t2</span>:<span class="ident">tt</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [<span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>:<span class="ident">expr</span>, $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">aa</span>:<span class="ident">expr</span>,)<span class="kw-2">*</span>] <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t1</span>:<span class="ident">tt</span> <span class="kw">in</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t2</span>:<span class="ident">tt</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">finish</span> (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">z</span>:<span class="ident">expr</span>) [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">aa</span>:<span class="ident">expr</span>,)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">p</span>:<span class="ident">pat</span>,)<span class="op">+</span>] <span class="kw">in</span> { $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>}) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [] [] <span class="ident">index</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">pat</span>, $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">exprs</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pats</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] <span class="kw-2">mut</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">x</span>:<span class="ident">ident</span> (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">expr</span>) $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">exprs</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pats</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] <span class="kw-2">mut</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">x</span>:<span class="ident">ident</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">exprs</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pats</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] , $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">exprs</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pats</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] <span class="kw-2">ref</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">x</span>:<span class="ident">ident</span> (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">expr</span>) $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">exprs</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pats</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] <span class="kw-2">ref</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">x</span>:<span class="ident">ident</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">exprs</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pats</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] <span class="macro-nonterminal">$</span><span class="macro-nonterminal">x</span>:<span class="ident">ident</span> (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">expr</span>) $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">exprs</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pats</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] <span class="macro-nonterminal">$</span><span class="macro-nonterminal">x</span>:<span class="ident">ident</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
(@<span class="ident">parse</span> [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">exprs</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] [$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pats</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>] $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
}</pre></div>
</div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Array zip macro: lock step function application across several arrays and
producers.</p>
<p>This is a shorthand for <a href="struct.Zip.html"><code>Zip</code></a>.</p>
<p>This example:</p>
<div class='information'><div class='tooltip ignore'>ⓘ</div></div><div class="example-wrap"><pre class="rust rust-example-rendered ignore">
<span class="macro">azip!</span>(<span class="kw-2">mut</span> <span class="ident">a</span>, <span class="ident">b</span>, <span class="ident">c</span> <span class="kw">in</span> { <span class="kw-2">*</span><span class="ident">a</span> <span class="op">=</span> <span class="ident">b</span> <span class="op">+</span> <span class="ident">c</span> })</pre></div>
<p>Is equivalent to:</p>
<div class='information'><div class='tooltip ignore'>ⓘ</div></div><div class="example-wrap"><pre class="rust rust-example-rendered ignore">
<span class="ident">Zip::from</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">a</span>).<span class="ident">and</span>(<span class="kw-2">&</span><span class="ident">b</span>).<span class="ident">and</span>(<span class="kw-2">&</span><span class="ident">c</span>).<span class="ident">apply</span>(<span class="op">|</span><span class="ident">a</span>, <span class="kw-2">&</span><span class="ident">b</span>, <span class="kw-2">&</span><span class="ident">c</span><span class="op">|</span> {
<span class="kw-2">*</span><span class="ident">a</span> <span class="op">=</span> <span class="ident">b</span> <span class="op">+</span> <span class="ident">c</span>;
});
</pre></div>
<p>Explanation of the shorthand for captures:</p>
<ul>
<li><code>mut a</code>: the producer is <code>&mut a</code> and the variable pattern is <code>mut a</code>.</li>
<li><code>b</code>: the producer is <code>&b</code> and the variable pattern is <code>&b</code> (same for <code>c</code>).</li>
</ul>
<p>The syntax is <code>azip!(</code> <em>[</em> <code>index</code> <em>pattern</em> <code>,</code><em>] capture [</em><code>,</code> <em>capture [</em><code>,</code> <em>…] ]</em> <code>in {</code> <em>expression</em> <code>})</code>
where the captures are a sequence of pattern-like items that indicate which
arrays are used for the zip. The <em>expression</em> is evaluated elementwise,
with the value of an element from each producer in their respective variable.</p>
<p>More capture rules:</p>
<ul>
<li><code>ref c</code>: the producer is <code>&c</code> and the variable pattern is <code>c</code>.</li>
<li><code>mut a (expr)</code>: the producer is <code>expr</code> and the variable pattern is <code>mut a</code>.</li>
<li><code>b (expr)</code>: the producer is <code>expr</code> and the variable pattern is <code>&b</code>.</li>
<li><code>ref c (expr)</code>: the producer is <code>expr</code> and the variable pattern is <code>c</code>.</li>
</ul>
<p>Special rule:</p>
<ul>
<li><code>index i</code>: Use <code>Zip::indexed</code> instead. <code>i</code> is a pattern – it can be
a single variable name or something else that pattern matches the index.
This rule must be the first if it is used, and it must be followed by
at least one other rule.</li>
</ul>
<p><strong>Panics</strong> if any of the arrays are not of the same shape.</p>
<h2 id="examples" class="section-header"><a href="#examples">Examples</a></h2>
<div class="example-wrap"><pre class="rust rust-example-rendered">
<span class="attribute">#[<span class="ident">macro_use</span>(<span class="ident">azip</span>)]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">ndarray</span>;
<span class="kw">use</span> <span class="ident">ndarray::Array2</span>;
<span class="kw">type</span> <span class="ident">M</span> <span class="op">=</span> <span class="ident">Array2</span><span class="op"><</span><span class="ident">f32</span><span class="op">></span>;
<span class="kw">fn</span> <span class="ident">main</span>() {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">a</span> <span class="op">=</span> <span class="ident">M::zeros</span>((<span class="number">16</span>, <span class="number">16</span>));
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">M::zeros</span>(<span class="ident">a</span>.<span class="ident">dim</span>());
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">c</span> <span class="op">=</span> <span class="ident">M::zeros</span>(<span class="ident">a</span>.<span class="ident">dim</span>());
<span class="comment">// set up values in b, c</span>
<span class="ident">b</span>.<span class="ident">fill</span>(<span class="number">1.</span>);
<span class="kw">for</span> ((<span class="ident">i</span>, <span class="ident">j</span>), <span class="ident">elt</span>) <span class="kw">in</span> <span class="ident">c</span>.<span class="ident">indexed_iter_mut</span>() {
<span class="kw-2">*</span><span class="ident">elt</span> <span class="op">=</span> (<span class="ident">i</span> <span class="op">+</span> <span class="number">10</span> <span class="op">*</span> <span class="ident">j</span>) <span class="kw">as</span> <span class="ident">f32</span>;
}
<span class="comment">// Compute a simple ternary operation:</span>
<span class="comment">// elementwise addition of b and c, stored in a</span>
<span class="macro">azip!</span>(<span class="kw-2">mut</span> <span class="ident">a</span>, <span class="ident">b</span>, <span class="ident">c</span> <span class="kw">in</span> { <span class="kw-2">*</span><span class="ident">a</span> <span class="op">=</span> <span class="ident">b</span> <span class="op">+</span> <span class="ident">c</span> });
<span class="macro">assert_eq!</span>(<span class="ident">a</span>, <span class="kw-2">&</span><span class="ident">b</span> <span class="op">+</span> <span class="kw-2">&</span><span class="ident">c</span>);
<span class="comment">// Example of azip!() with index</span>
<span class="macro">azip!</span>(<span class="ident">index</span> (<span class="ident">i</span>, <span class="ident">j</span>), <span class="ident">b</span>, <span class="ident">c</span> <span class="kw">in</span> {
<span class="ident">a</span>[[<span class="ident">i</span>, <span class="ident">j</span>]] <span class="op">=</span> <span class="ident">b</span> <span class="op">-</span> <span class="ident">c</span>;
});
<span class="macro">assert_eq!</span>(<span class="ident">a</span>, <span class="kw-2">&</span><span class="ident">b</span> <span class="op">-</span> <span class="kw-2">&</span><span class="ident">c</span>);
}</pre></div>
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