# \[Bug #3708\] Array#permutation $B$,$\*$+$7$J7k2L$rJV$9(B

**URL:** <https://www.ruby-forum.com/t/bug-3708-array-permutation-b-7-j7k2l-rjv-9-b/193468>\
**Category:** Development\
**Created:** [August 18, 2010, 9:34am UTC](https://www.ruby-forum.com/t/bug-3708-array-permutation-b-7-j7k2l-rjv-9-b/193468 "2010-08-18T09:34:23Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Shumpei\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/6de8d8/32.png) [@Shumpei\_A](https://www.ruby-forum.com/u/Shumpei_A)\
**Post date:** [August 18, 2010, 9:34am UTC](https://www.ruby-forum.com/t/bug-3708-array-permutation-b-7-j7k2l-rjv-9-b/193468/1 "2010-08-18T09:34:23Z")

</div>

Bug #3708: Array#permutation e$B$,$\*$+$7$J7k2L$rJV$9e(B  
[http://redmine.ruby-lang.org/issues/show/3708](http://redmine.ruby-lang.org/issues/show/3708)

e$B5/I\<\<Te(B: Shumpei A.  
e$B%9%F!\<%?%9e(B: Open, e$BM%@hEYe(B: Normal  
ruby -v: ruby 1.9.3dev (2010-08-18 trunk 29024) [x86\_64-darwin10.4.0]

Array#permutatione$B$N7k2L$K!$G[Ns$K4^$^$l$F$$$J$$$O$:$NCM$,F~$C$F$$$^$9e(B

% ./ruby\_head -e “p [0,1,2,3,4][1,4].permutation.to\_a”  
[[0, 1, 2, 3], [0, 1, 3, 2], [0, 2, 1, 3], [0, 2, 3, 1], [0, 3, 1, 2],  
[0, 3, 2, 1], [1, 0, 2, 3], [1, 0, 3, 2], [1, 2, 0, 3], [1, 2, 3, 0],  
[1, 3, 0, 2], [1, 3, 2, 0], [2, 0, 1, 3], [2, 0, 3, 1], [2, 1, 0, 3],  
[2, 1, 3, 0], [2, 3, 0, 1], [2, 3, 1, 0], [3, 0, 1, 2], [3, 0, 2, 1],  
[3, 1, 0, 2], [3, 1, 2, 0], [3, 2, 0, 1], [3, 2, 1, 0]]

[0,1,2,3,4][1,4] e$B$Oe(B [1, 2, 3, 4]  
e$B$J$N$Ge(B0e$B$O4^$^$l$J$$$O$:$G$9!%e(B

% ./ruby\_head -e “p [0,1,2,3][1,3].permutation.to\_a”  
e$B$@$H@5$7$/F0$-$^$9e(B

---

<div class="post-metadata">

**Author:** ![Shumpei\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/6de8d8/32.png) [@Shumpei\_A](https://www.ruby-forum.com/u/Shumpei_A)\
**Post date:** [August 18, 2010, 11:24am UTC](https://www.ruby-forum.com/t/bug-3708-array-permutation-b-7-j7k2l-rjv-9-b/193468/2 "2010-08-18T11:24:27Z")

</div>

e$B$`$i$?$G$9!#e(B

On 2010/08/18, at 16:33, Shumpei A. wrote:

> e$B$@$H@5$7$/F0$-$^$9e(B  
> ary\_make\_shared e$B4X?t$r0J2\<$N$h$&$K=$@5$9$k$H@5\>o$KF0:n$7$^$9!#e(B

diff --git a/array.c b/array.c  
index 51d3ad2…ea4fe43 100644  
— a/array.c  
+++ b/array.c  
@@ -409,10 +409,7 @@ static VALUE  
ary\_make\_shared(VALUE ary)  
{  
assert(!ARY\_EMBED\_P(ary));

- if (ARY\_SHARED\_P(ary)) {
- 

```
  return ARY_SHARED(ary);

```

- }
- else if (ARY\_SHARED\_ROOT\_P(ary)) {

- if (ARY\_SHARED\_P(ary) || ARY\_SHARED\_ROOT\_P(ary)) {  
return ary;  
}  
else if (OBJ\_FROZEN(ary)) {  
diff --git a/test/ruby/test\_array.rb b/test/ruby/test\_array.rb  
index e8edcc2…f2d723f 100644  
— a/test/ruby/test\_array.rb  
+++ b/test/ruby/test\_array.rb  
@@ -1549,6 +1549,9 @@ class TestArray \< Test::Unit::TestCase  
a.permutation {|x| b \<\< x; a.replace(@cls[9, 8, 7, 6]) }  
assert\_equal(@cls[9, 8, 7, 6], a)  
assert\_equal(@cls[1, 2, 3, 4].permutation.to\_a, b)
- 
- bug3708 = ‘[ruby-dev:42067]’
- assert\_equal(b, @cls[0, 1, 2, 3, 4][1, 4].permutation.to\_a,  
bug3708)  
end

def test\_repeated\_permutation

–  
Kenta M.  
OpenPGP FP = 1D69 ADDE 081C 9CC2 2E54 98C1 CEFE 8AFB 6081 B062

e$BK$r=q$-$^$7$?e(B!!  
e$B!Xe(BRuby e$B5U0z$-%l%7%T!Ye(B

> **[Ruby 逆引きレシピ すぐに美味しいサンプル&amp;テクニック 232 (PROGRAMMER’S RECIPE) | 島田 浩二, 設樂 洋爾, 村田...](https://www.amazon.co.jp/%E9%80%86%E5%BC%95%E3%81%8D%E3%83%AC%E3%82%B7%E3%83%94-%E3%81%99%E3%81%90%E3%81%AB%E7%BE%8E%E5%91%B3%E3%81%97%E3%81%84%E3%82%B5%E3%83%B3%E3%83%97%E3%83%AB-%E3%83%86%E3%82%AF%E3%83%8B%E3%83%83%E3%82%AF-PROGRAMMER%E2%80%99S-RECIPE/dp/4798119881)**
>
> Amazonで島田 浩二, 設樂 洋爾, 村田 賢太, 前田 智樹, 谷口 文威のRuby 逆引きレシピ すぐに美味しいサンプル&テクニック 232 (PROGRAMMER’S RECIPE)。アマゾンならポイント還元本が多数。島田 浩二, 設樂 洋爾, 村田 賢太, 前田 智樹, 谷口 文威作品ほか、お急ぎ便対象商品は当日お届けも可能。またRuby 逆引きレシピ すぐに美味しいサンプル&テクニック 232 (PROGRAMMER’S RECIPE)もアマゾン配送商品なら通常配送無料。

E-mail: removed\_email\_address@domain.invalid  
twitter: [http://twitter.com/mrkn/](http://twitter.com/mrkn/)  
blog: [ドレッシングのような](http://d.hatena.ne.jp/mrkn/)

---

<div class="post-metadata">

**Author:** ![Shumpei\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/6de8d8/32.png) [@Shumpei\_A](https://www.ruby-forum.com/u/Shumpei_A)\
**Post date:** [August 18, 2010, 12:00pm UTC](https://www.ruby-forum.com/t/bug-3708-array-permutation-b-7-j7k2l-rjv-9-b/193468/3 "2010-08-18T12:00:10Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:42068] Re: [Bug #3708] Array#permutation  
e$B$,$\*$+$7$J7k2L$rJV$9e(B”  
on Wed, 18 Aug 2010 18:16:13 +0900, Kenta M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|On 2010/08/18, at 16:33, Shumpei A. wrote:  
|  
|\> Array#permutatione$B$N7k2L$K!$G[Ns$K4^$^$l$F$$$J$$$O$:$NCM$,F~$C$F$$$^$9e(B  
|\>  
|\> % ./ruby\_head -e “p [0,1,2,3,4][1,4].permutation.to\_a”  
|\> [[0, 1, 2, 3], [0, 1, 3, 2], [0, 2, 1, 3], [0, 2, 3, 1], [0, 3, 1, 2], [0, 3, 2, 1], [1, 0, 2, 3], [1, 0, 3, 2], [1, 2, 0, 3], [1, 2, 3, 0], [1, 3, 0, 2], [1, 3, 2, 0], [2, 0, 1, 3], [2, 0, 3, 1], [2, 1, 0, 3], [2, 1, 3, 0], [2, 3, 0, 1], [2, 3, 1, 0], [3, 0, 1, 2], [3, 0, 2, 1], [3, 1, 0, 2], [3, 1, 2, 0], [3, 2, 0, 1], [3, 2, 1, 0]]  
|\>  
|\>  
|\> [0,1,2,3,4][1,4] e$B$Oe(B [1, 2, 3, 4] e$B$J$N$Ge(B0e$B$O4^$^$l$J$$$O$:$G$9!%e(B  
|\>  
|\>  
|\> % ./ruby\_head -e “p [0,1,2,3][1,3].permutation.to\_a”  
|\> e$B$@$H@5$7$/F0$-$^$9e(B  
|  
|  
|ary\_make\_shared e$B4X?t$r0J2\<$N$h$&$K=$@5$9$k$H@5\>o$KF0:n$7$^$9!#e(B  
|  
|diff --git a/array.c b/array.c  
|index 51d3ad2…ea4fe43 100644  
|— a/array.c  
|+++ b/array.c  
|@@ -409,10 +409,7 @@ static VALUE  
| ary\_make\_shared(VALUE ary)  
| {  
| assert(!ARY\_EMBED\_P(ary));  
|- if (ARY\_SHARED\_P(ary)) {  
|- return ARY\_SHARED(ary);  
|- }  
|- else if (ARY\_SHARED\_ROOT\_P(ary)) {  
|+ if (ARY\_SHARED\_P(ary) || ARY\_SHARED\_ROOT\_P(ary)) {  
| return ary;  
| }  
| else if (OBJ\_FROZEN(ary)) {

e$B$J$k$[$I!#%3%\_%C%H$7$F2\<$5$$!#e(B

---

<div class="post-metadata">

**Author:** ![Shumpei\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/6de8d8/32.png) [@Shumpei\_A](https://www.ruby-forum.com/u/Shumpei_A)\
**Post date:** [August 18, 2010, 12:52pm UTC](https://www.ruby-forum.com/t/bug-3708-array-permutation-b-7-j7k2l-rjv-9-b/193468/4 "2010-08-18T12:52:16Z")

</div>

e$B$`$i$?$G$9!#e(B

On 2010/08/18, at 18:28, Yukihiro M. wrote:

> |- }  
> |- else if (ARY\_SHARED\_ROOT\_P(ary)) {  
> |+ if (ARY\_SHARED\_P(ary) || ARY\_SHARED\_ROOT\_P(ary)) {  
> | return ary;  
> | }  
> | else if (OBJ\_FROZEN(ary)) {
> 
> e$B$J$k$[$I!#%3%\_%C%H$7$F2\<$5$$!#e(B

e$B0lC6$3$l$G%3%\_%C%H$7$?$N$G$9$,!“e(BSEGV  
e$B$,H/@8$9$k$3$H$,$”$C$?$?$ae(B revert e$B$7$^$7$?!#e(B

e$B$J$+$@$5$s$Ke(B ary\_make\_shared\_copy  
e$B$r65$($F$b$i$C$?$N$G!"$b$&0lEY=$@50F$rDs\<($7$^$9!#e(B  
repeated\_permutatione$B!"e(Brepeated\_combinatione$B!"e(Bproduct  
e$B$bBP\>]$G$9!#e(B

diff --git a/array.c b/array.c  
index 51d3ad2…bca7956 100644  
— a/array.c  
+++ b/array.c  
@@ -4010,7 +4010,7 @@ rb\_ary\_permutation(int argc, VALUE \*argv, VALUE  
ary)  
long _p = (long_)RSTRING\_PTR(t0);  
volatile VALUE t1 = tmpbuf(n,sizeof(char));  
char _used = (char_)RSTRING\_PTR(t1);

- 

```
  VALUE ary0 = ary_make_substitution(ary); /* private defensive 

```

copy of ary \*/

- 

```
  VALUE ary0 = ary_make_shared_copy(ary); /* private defensive 

```

copy of ary \*/  
RBASIC(ary0)-\>klass = 0;

```
    MEMZERO(used, char, n); /* initialize array */

```

@@ -4180,7 +4180,7 @@ rb\_ary\_repeated\_permutation(VALUE ary, VALUE num)  
else { /\* this is the general case \*/  
volatile VALUE t0 = tmpbuf(r, sizeof(long));  
long _p = (long_)RSTRING\_PTR(t0);

- 

```
  VALUE ary0 = ary_make_substitution(ary); /* private defensive 

```

copy of ary \*/

- 

```
  VALUE ary0 = ary_make_shared_copy(ary); /* private defensive 

```

copy of ary \*/  
RBASIC(ary0)-\>klass = 0;

```
    rpermute0(n, r, p, 0, ary0); /* compute and yield repeated 

```

permutations \*/  
@@ -4266,7 +4266,7 @@ rb\_ary\_repeated\_combination(VALUE ary, VALUE num)  
else {  
volatile VALUE t0 = tmpbuf(n, sizeof(long));  
long _p = (long_)RSTRING\_PTR(t0);

- 

```
  VALUE ary0 = ary_make_substitution(ary); /* private defensive 

```

copy of ary \*/

- 

```
  VALUE ary0 = ary_make_shared_copy(ary); /* private defensive 

```

copy of ary \*/  
RBASIC(ary0)-\>klass = 0;

```
    rcombinate0(len, n, p, 0, n, ary0); /* compute and yield 

```

repeated combinations \*/  
@@ -4325,7 +4325,7 @@ rb\_ary\_product(int argc, VALUE _argv, VALUE ary)  
/_ Make defensive copies of arrays; exit if any is empty \*/  
for (i = 0; i \< n; i++) {  
if (RARRAY\_LEN(arrays[i]) == 0) goto done;

- 

```
      arrays[i] = ary_make_substitution(arrays[i]);

```

- 

```
      arrays[i] = ary_make_shared_copy(arrays[i]);
  }

```

}  
else {  
— a/test/ruby/test\_array.rb  
+++ b/test/ruby/test\_array.rb  
@@ -1528,6 +1528,10 @@ class TestArray \< Test::Unit::TestCase  
acc = [1,2].product(\*[o]\*10)  
assert\_equal([1,2].product([3,4], [3,4], [3,4], [3,4], [3,4],  
[3,4], [3,4], [3,4], [3,4], [3,4]),  
acc)
- 
- a = []
- [1, 2].product([0, 1, 2, 3, 4][1, 4]) {|x| a \<\< x }
- assert(a.all?{|x| !x.include?(0) })  
end

def test\_permutation  
@@ -1574,6 +1578,9 @@ class TestArray \< Test::Unit::TestCase  
a.repeated\_permutation(4) {|x| b \<\< x; a.replace(@cls[9, 8, 7, 6])  
}  
assert\_equal(@cls[9, 8, 7, 6], a)  
assert\_equal(@cls[1, 2, 3, 4].repeated\_permutation(4).to\_a, b)  
+

- a = @cls[0, 1, 2, 3, 4][1, 4].repeated\_permutation(2)
- assert(a.all?{|x| !x.include?(0) })  
end

def test\_repeated\_combination  
@@ -1600,6 +1607,9 @@ class TestArray \< Test::Unit::TestCase  
a.repeated\_combination(4) {|x| b \<\< x; a.replace(@cls[9, 8, 7, 6])  
}  
assert\_equal(@cls[9, 8, 7, 6], a)  
assert\_equal(@cls[1, 2, 3, 4].repeated\_combination(4).to\_a, b)  
+

- a = @cls[0, 1, 2, 3, 4][1, 4].repeated\_combination(2)
- assert(a.all?{|x| !x.include?(0) })  
end

def test\_take

–  
Kenta M.  
OpenPGP FP = 1D69 ADDE 081C 9CC2 2E54 98C1 CEFE 8AFB 6081 B062

e$BK$r=q$-$^$7$?e(B!!  
e$B!Xe(BRuby e$B5U0z$-%l%7%T!Ye(B

> **[Ruby 逆引きレシピ すぐに美味しいサンプル&amp;テクニック 232 (PROGRAMMER’S RECIPE) | 島田 浩二, 設樂 洋爾, 村田...](https://www.amazon.co.jp/%E9%80%86%E5%BC%95%E3%81%8D%E3%83%AC%E3%82%B7%E3%83%94-%E3%81%99%E3%81%90%E3%81%AB%E7%BE%8E%E5%91%B3%E3%81%97%E3%81%84%E3%82%B5%E3%83%B3%E3%83%97%E3%83%AB-%E3%83%86%E3%82%AF%E3%83%8B%E3%83%83%E3%82%AF-PROGRAMMER%E2%80%99S-RECIPE/dp/4798119881)**
>
> Amazonで島田 浩二, 設樂 洋爾, 村田 賢太, 前田 智樹, 谷口 文威のRuby 逆引きレシピ すぐに美味しいサンプル&テクニック 232 (PROGRAMMER’S RECIPE)。アマゾンならポイント還元本が多数。島田 浩二, 設樂 洋爾, 村田 賢太, 前田 智樹, 谷口 文威作品ほか、お急ぎ便対象商品は当日お届けも可能。またRuby 逆引きレシピ すぐに美味しいサンプル&テクニック 232 (PROGRAMMER’S RECIPE)もアマゾン配送商品なら通常配送無料。

E-mail: removed\_email\_address@domain.invalid  
twitter: [http://twitter.com/mrkn/](http://twitter.com/mrkn/)  
blog: [ドレッシングのような](http://d.hatena.ne.jp/mrkn/)