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Clarify determinism of Go playground w.r.t. random numbers

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Fixes #443
This commit is contained in:
Eli Bendersky 2022-09-22 07:05:32 -07:00
parent 00543ca6f7
commit cc804d764b
4 changed files with 18 additions and 7 deletions
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2
examples/random-numbers/random-numbers.go
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@ -32,7 +32,7 @@ func main() {
// produce the same sequence of numbers each time by default. // produce the same sequence of numbers each time by default.
// To produce varying sequences, give it a seed that changes. // To produce varying sequences, give it a seed that changes.
// Note that this is not safe to use for random numbers you // Note that this is not safe to use for random numbers you
// intend to be secret, use `crypto/rand` for those. // intend to be secret; use `crypto/rand` for those.
s1 := rand.NewSource(time.Now().UnixNano()) s1 := rand.NewSource(time.Now().UnixNano())
r1 := rand.New(s1) r1 := rand.New(s1)

4
examples/random-numbers/random-numbers.hash
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@ -1,2 +1,2 @@
f0f88939692a32975d902c94066537a6ba5ab96f ea6a386e4e5602247b2203fa433d4419ff5a9489
RaoKyUd9tgC Enb5uJEx0Bt

5
examples/random-numbers/random-numbers.sh
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@ -1,3 +1,8 @@
# Depending on where you run this sample, some of the
# generated numbers may be different. Note that on
# the Go playground seeding with `time.Now()` still
# produces deterministic results due to the way the
# playground is implemented.
$ go run random-numbers.go $ go run random-numbers.go
81,87 81,87
0.6645600532184904 0.6645600532184904

12
public/random-numbers generated
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@ -43,7 +43,7 @@ generation.</p>
</td> </td>
<td class="code leading"> <td class="code leading">
<a href="https://go.dev/play/p/RaoKyUd9tgC"><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/Enb5uJEx0Bt"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span> <pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
</pre> </pre>
</td> </td>
@ -127,7 +127,7 @@ other ranges, for example <code>5.0 &lt;= f' &lt; 10.0</code>.</p>
produce the same sequence of numbers each time by default. produce the same sequence of numbers each time by default.
To produce varying sequences, give it a seed that changes. To produce varying sequences, give it a seed that changes.
Note that this is not safe to use for random numbers you Note that this is not safe to use for random numbers you
intend to be secret, use <code>crypto/rand</code> for those.</p> intend to be secret; use <code>crypto/rand</code> for those.</p>
</td> </td>
<td class="code leading"> <td class="code leading">
@ -184,11 +184,17 @@ produces the same sequence of random numbers.</p>
<tr> <tr>
<td class="docs"> <td class="docs">
<p>Depending on where you run this sample, some of the
generated numbers may be different. Note that on
the Go playground seeding with <code>time.Now()</code> still
produces deterministic results due to the way the
playground is implemented.</p>
</td> </td>
<td class="code leading"> <td class="code leading">
<pre class="chroma"><span class="gp">$</span> go run random-numbers.go <pre class="chroma">
<span class="gp">$</span> go run random-numbers.go
<span class="go">81,87 <span class="go">81,87
</span><span class="go">0.6645600532184904 </span><span class="go">0.6645600532184904
</span><span class="go">7.123187485356329,8.434115364335547 </span><span class="go">7.123187485356329,8.434115364335547