Update random-numbers example to use Go 1.22's math/rand/v2

Fixes #507
2024-02-07 06:27:04 -08:00
parent 1143b547d7
commit 5aa9ad70f3
4 changed files with 58 additions and 44 deletions
--- a/examples/random-numbers/random-numbers.go
+++ b/examples/random-numbers/random-numbers.go
@@ -1,4 +1,4 @@
-// Go's `math/rand` package provides
+// Go's `math/rand/v2` package provides
 // [pseudorandom number](https://en.wikipedia.org/wiki/Pseudorandom_number_generator)
 // generation.

@@ -6,15 +6,15 @@ package main

 import (
 	"fmt"
-	"math/rand"
+	"math/rand/v2"
 )

 func main() {

-	// For example, `rand.Intn` returns a random `int` n,
+	// For example, `rand.IntN` returns a random `int` n,
 	// `0 <= n < 100`.
-	fmt.Print(rand.Intn(100), ",")
-	fmt.Print(rand.Intn(100))
+	fmt.Print(rand.IntN(100), ",")
+	fmt.Print(rand.IntN(100))
 	fmt.Println()

 	// `rand.Float64` returns a `float64` `f`,
@@ -27,18 +27,21 @@ func main() {
 	fmt.Print((rand.Float64() * 5) + 5)
 	fmt.Println()

-	// If you want a known seed, `NewSource` returns
-	// a `rand.Source` value that can be used to
-	// seed a new generator. The same seed will produce
-	// the same sequence of random numbers.
-	s2 := rand.NewSource(42)
+	// If you want a known seed, create a new
+	// `rand.Source` and pass it into the `New`
+	// constructor. `NewPCG` creates a new
+	// [PCG](https://en.wikipedia.org/wiki/Permuted_congruential_generator)
+	// source that requires a seed of two `uint64`
+	// numbers.
+	s2 := rand.NewPCG(42, 1024)
 	r2 := rand.New(s2)
-	fmt.Print(r2.Intn(100), ",")
-	fmt.Print(r2.Intn(100))
+	fmt.Print(r2.IntN(100), ",")
+	fmt.Print(r2.IntN(100))
 	fmt.Println()
-	s3 := rand.NewSource(42)
+
+	s3 := rand.NewPCG(42, 1024)
 	r3 := rand.New(s3)
-	fmt.Print(r3.Intn(100), ",")
-	fmt.Print(r3.Intn(100))
+	fmt.Print(r3.IntN(100), ",")
+	fmt.Print(r3.IntN(100))
 	fmt.Println()
 }
--- a/examples/random-numbers/random-numbers.hash
+++ b/examples/random-numbers/random-numbers.hash
@@ -1,2 +1,2 @@
-1106f890032a51d24bb0a01d7e234c29b4fce005
-Op7Udbk3k8K
+76b8f86171ffcf9e7d5781fdf50c050a824acd9b
+TkgmNAl8euK
--- a/examples/random-numbers/random-numbers.sh
+++ b/examples/random-numbers/random-numbers.sh
@@ -1,12 +1,12 @@
 # Some of the generated numbers may be
 # different when you run the sample.
 $ go run random-numbers.go
-44,20
+68,56
 0.8090228139659177
 5.840125017402497,6.937056298890035
-5,87
-5,87
+94,49
+94,49

-# See the [`math/rand`](https://pkg.go.dev/math/rand)
+# See the [`math/rand/v2`](https://pkg.go.dev/math/rand/v2)
 # package docs for references on other random quantities
 # that Go can provide.
--- a/public/random-numbers
+++ b/public/random-numbers
@@ -27,7 +27,7 @@
        
        <tr>
          <td class="docs">
-            <p>Go&rsquo;s <code>math/rand</code> package provides
+            <p>Go&rsquo;s <code>math/rand/v2</code> package provides
 <a href="https://en.wikipedia.org/wiki/Pseudorandom_number_generator">pseudorandom number</a>
 generation.</p>

@@ -43,7 +43,7 @@ generation.</p>
            
          </td>
          <td class="code leading">
-            <a href="https://go.dev/play/p/Op7Udbk3k8K"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
+            <a href="https://go.dev/play/p/TkgmNAl8euK"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
          <pre class="chroma"><code><span class="line"><span class="cl"><span class="kn">package</span> <span class="nx">main</span></span></span></code></pre>
          </td>
        </tr>
@@ -56,7 +56,7 @@ generation.</p>
            
          <pre class="chroma"><code><span class="line"><span class="cl"><span class="kn">import</span> <span class="p">(</span>
 </span></span><span class="line"><span class="cl">    <span class="s">&#34;fmt&#34;</span>
-</span></span><span class="line"><span class="cl">    <span class="s">&#34;math/rand&#34;</span>
+</span></span><span class="line"><span class="cl">    <span class="s">&#34;math/rand/v2&#34;</span>
 </span></span><span class="line"><span class="cl"><span class="p">)</span></span></span></code></pre>
          </td>
        </tr>
@@ -73,14 +73,14 @@ generation.</p>
        
        <tr>
          <td class="docs">
-            <p>For example, <code>rand.Intn</code> returns a random <code>int</code> n,
+            <p>For example, <code>rand.IntN</code> returns a random <code>int</code> n,
 <code>0 &lt;= n &lt; 100</code>.</p>

          </td>
          <td class="code leading">
            
-          <pre class="chroma"><code><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">rand</span><span class="p">.</span><span class="nf">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&#34;,&#34;</span><span class="p">)</span>
-</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">rand</span><span class="p">.</span><span class="nf">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
+          <pre class="chroma"><code><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">rand</span><span class="p">.</span><span class="nf">IntN</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&#34;,&#34;</span><span class="p">)</span>
+</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">rand</span><span class="p">.</span><span class="nf">IntN</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
 </span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">()</span></span></span></code></pre>
          </td>
        </tr>
@@ -113,23 +113,34 @@ other ranges, for example <code>5.0 &lt;= f' &lt; 10.0</code>.</p>
        
        <tr>
          <td class="docs">
-            <p>If you want a known seed, <code>NewSource</code> returns
-a <code>rand.Source</code> value that can be used to
-seed a new generator. The same seed will produce
-the same sequence of random numbers.</p>
+            <p>If you want a known seed, create a new
+<code>rand.Source</code> and pass it into the <code>New</code>
+constructor. <code>NewPCG</code> creates a new
+<a href="https://en.wikipedia.org/wiki/Permuted_congruential_generator">PCG</a>
+source that requires a seed of two <code>uint64</code>
+numbers.</p>

+          </td>
+          <td class="code leading">
+            
+          <pre class="chroma"><code><span class="line"><span class="cl">    <span class="nx">s2</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nf">NewPCG</span><span class="p">(</span><span class="mi">42</span><span class="p">,</span> <span class="mi">1024</span><span class="p">)</span>
+</span></span><span class="line"><span class="cl">    <span class="nx">r2</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nf">New</span><span class="p">(</span><span class="nx">s2</span><span class="p">)</span>
+</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">r2</span><span class="p">.</span><span class="nf">IntN</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&#34;,&#34;</span><span class="p">)</span>
+</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">r2</span><span class="p">.</span><span class="nf">IntN</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
+</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">()</span></span></span></code></pre>
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            
          </td>
          <td class="code">
            
-          <pre class="chroma"><code><span class="line"><span class="cl">    <span class="nx">s2</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nf">NewSource</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span>
-</span></span><span class="line"><span class="cl">    <span class="nx">r2</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nf">New</span><span class="p">(</span><span class="nx">s2</span><span class="p">)</span>
-</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">r2</span><span class="p">.</span><span class="nf">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&#34;,&#34;</span><span class="p">)</span>
-</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">r2</span><span class="p">.</span><span class="nf">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
-</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">()</span>
-</span></span><span class="line"><span class="cl">    <span class="nx">s3</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nf">NewSource</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span>
+          <pre class="chroma"><code><span class="line"><span class="cl">    <span class="nx">s3</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nf">NewPCG</span><span class="p">(</span><span class="mi">42</span><span class="p">,</span> <span class="mi">1024</span><span class="p">)</span>
 </span></span><span class="line"><span class="cl">    <span class="nx">r3</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nf">New</span><span class="p">(</span><span class="nx">s3</span><span class="p">)</span>
-</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">r3</span><span class="p">.</span><span class="nf">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&#34;,&#34;</span><span class="p">)</span>
-</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">r3</span><span class="p">.</span><span class="nf">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
+</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">r3</span><span class="p">.</span><span class="nf">IntN</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&#34;,&#34;</span><span class="p">)</span>
+</span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Print</span><span class="p">(</span><span class="nx">r3</span><span class="p">.</span><span class="nf">IntN</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
 </span></span><span class="line"><span class="cl">    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">()</span>
 </span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre>
          </td>
@@ -148,17 +159,17 @@ different when you run the sample.</p>
          <td class="code leading">
            
          <pre class="chroma"><code><span class="line"><span class="cl"><span class="gp">$</span> go run random-numbers.go
-</span></span><span class="line"><span class="cl"><span class="go">44,20
+</span></span><span class="line"><span class="cl"><span class="go">68,56
 </span></span></span><span class="line"><span class="cl"><span class="go">0.8090228139659177
 </span></span></span><span class="line"><span class="cl"><span class="go">5.840125017402497,6.937056298890035
-</span></span></span><span class="line"><span class="cl"><span class="go">5,87
-</span></span></span><span class="line"><span class="cl"><span class="go">5,87</span></span></span></code></pre>
+</span></span></span><span class="line"><span class="cl"><span class="go">94,49
+</span></span></span><span class="line"><span class="cl"><span class="go">94,49</span></span></span></code></pre>
          </td>
        </tr>
        
        <tr>
          <td class="docs">
-            <p>See the <a href="https://pkg.go.dev/math/rand"><code>math/rand</code></a>
+            <p>See the <a href="https://pkg.go.dev/math/rand/v2"><code>math/rand/v2</code></a>
 package docs for references on other random quantities
 that Go can provide.</p>

@@ -184,7 +195,7 @@ that Go can provide.</p>
    </div>
    <script>
      var codeLines = [];
-      codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A    \"fmt\"\u000A    \"math/rand\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push('    fmt.Print(rand.Intn(100), \",\")\u000A    fmt.Print(rand.Intn(100))\u000A    fmt.Println()\u000A');codeLines.push('    fmt.Println(rand.Float64())\u000A');codeLines.push('    fmt.Print((rand.Float64()*5)+5, \",\")\u000A    fmt.Print((rand.Float64() * 5) + 5)\u000A    fmt.Println()\u000A');codeLines.push('    s2 :\u003D rand.NewSource(42)\u000A    r2 :\u003D rand.New(s2)\u000A    fmt.Print(r2.Intn(100), \",\")\u000A    fmt.Print(r2.Intn(100))\u000A    fmt.Println()\u000A    s3 :\u003D rand.NewSource(42)\u000A    r3 :\u003D rand.New(s3)\u000A    fmt.Print(r3.Intn(100), \",\")\u000A    fmt.Print(r3.Intn(100))\u000A    fmt.Println()\u000A}\u000A');codeLines.push('');codeLines.push('');
+      codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A    \"fmt\"\u000A    \"math/rand/v2\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push('    fmt.Print(rand.IntN(100), \",\")\u000A    fmt.Print(rand.IntN(100))\u000A    fmt.Println()\u000A');codeLines.push('    fmt.Println(rand.Float64())\u000A');codeLines.push('    fmt.Print((rand.Float64()*5)+5, \",\")\u000A    fmt.Print((rand.Float64() * 5) + 5)\u000A    fmt.Println()\u000A');codeLines.push('    s2 :\u003D rand.NewPCG(42, 1024)\u000A    r2 :\u003D rand.New(s2)\u000A    fmt.Print(r2.IntN(100), \",\")\u000A    fmt.Print(r2.IntN(100))\u000A    fmt.Println()\u000A');codeLines.push('    s3 :\u003D rand.NewPCG(42, 1024)\u000A    r3 :\u003D rand.New(s3)\u000A    fmt.Print(r3.IntN(100), \",\")\u000A    fmt.Print(r3.IntN(100))\u000A    fmt.Println()\u000A}\u000A');codeLines.push('');codeLines.push('');
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