# Trying to make Array#collect massively parallel with OpenMP

**URL:** <https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479>\
**Category:** Ruby\
**Created:** [March 11, 2007, 9:10pm UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479 "2007-03-11T21:10:48Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 11, 2007, 9:10pm UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/1 "2007-03-11T21:10:48Z")

</div>

Hi all,

Windows XP Home  
VC++ 8 (free edition)

Just for kicks I tried creating a parallel Array#collect method, which  
I called Array#acollect (asynch. collect). I added the following C  
code to array.c, rebuilt and reinstalled, but it doesn’t seem to be  
any faster. Could this be an issue with my compiler? Or a Windows  
thing?

static VALUE rb\_ary\_acollect(VALUE ary){  
long i;  
VALUE collect;

if (!rb\_block\_given\_p())  
return rb\_ary\_new4(RARRAY(ary)-\>len, RARRAY(ary)-\>ptr);

collect = rb\_ary\_new2(RARRAY(ary)-\>len);

#pragma omp parallel for  
for (i = 0; i \< RARRAY(ary)-\>len; i++)  
rb\_ary\_push(collect, rb\_yield(RARRAY(ary)-\>ptr[i]));

return collect;  
}

rb\_define\_method(rb\_cArray, “acollect”, rb\_ary\_acollect, 0);

# bench\_collect.rb

require “benchmark”

MAX = 4000

array = []  
MAX.times{ |n|  
array[n] = 2 \* n  
}

# No significant difference (?)

Benchmark.bm(30) do |x|  
x.report(“Array#collect”){  
MAX.times{ array.collect{ |e| e += 4 } }  
}  
x.report(“Array#acollect”){  
MAX.times{ array.acollect{ |e| e += 4 } }  
}  
end

Ideas?

Thanks,

Dan

---

<div class="post-metadata">

**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 11, 2007, 11:38pm UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/2 "2007-03-11T23:38:05Z")

</div>

On 3/11/07, Daniel B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> ```
> for (i = 0; i < RARRAY(ary)->len; i++)
> 
> ```
> 
> MAX = 4000  
> }  
> x.report(“Array#acollect”){  
> MAX.times{ array.acollect{ |e| e += 4 } }  
> }  
> end
> 
> Ideas?
> 
> Thanks,
> 
> Dan

Hi,

I’m no expert in either ruby internals or openmp. I’ve just a few  
ideas for you (though most of them will be obvious probably):

1. [http://msdn2.microsoft.com/en-us/library/fw509c3b(VS.80).aspx](http://msdn2.microsoft.com/en-us/library/fw509c3b(VS.80).aspx) says  
you need to add /openmp compiler switch (try using \_OPENMP define to  
see if the compiler recognizes omp pragmas). #include “omp.h” might  
help as well.

2. in the same page they say you won’t see any difference if the whole  
loop runs under 15 ms on a specific machine (i.e. the thread startup  
time)

3. try running one loop outside the benchmark to setup the thread pool

4. is the assignment intentional (e += 4)?

5. (just for my curiosity:) are you using 1.8 or 1.9?

6. I’ve heard that 1.8 interpreter runs in one thred. I suppose your  
code runs correctly with multiple threads because there should not be  
any (re)allocations (e.g. it might crash if there was a local var in  
the block). Right?

7. what machine are you running this code on? (if you send me the  
binary or patch I might try it on my core2 machine if that helps)

8. I suppose the difference might be bigger if you used more  
complicated (longer) block (relates to #2)

9. if everything fails, try running pure c loops (without calling ruby  
functions) with omp optimisation, possibly wrapped into a ruby  
function to see if omp makes at least difference at c level

ok, I’ve run out of ideas for now…

Jano

---

<div class="post-metadata">

**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 12, 2007, 5:56am UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/3 "2007-03-12T05:56:37Z")

</div>

On Mar 11, 4:37 pm, “Jan S.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > I called Array#acollect (asynch. collect). I added the following C
> 
> > # No significant difference (?)
> 
> you need to add /openmp compiler switch (try using \_OPENMP define to  
> see if the compiler recognizes omp pragmas). #include “omp.h” might  
> help as well.

Ah, thanks. I tried that and I got:

LINK : fatal error LNK1104: cannot open file ‘VCOMP.lib’

It doesn’t look like I have omp.h. This may be a header that’s not  
included in the free version of VC++. I’ll have to ask around.

Thanks,

Dan

---

<div class="post-metadata">

**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 12, 2007, 7:06pm UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/4 "2007-03-12T19:06:21Z")

</div>

On Mar 12, 3:52 am, “Jan S.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > > > long i;
> 
> > > > array = []  
> > > > MAX.times{ array.acollect{ |e| e += 4 } }
> 
> > LINK : fatal error LNK1104: cannot open file ‘VCOMP.lib’
> 
> > It doesn’t look like I have omp.h. This may be a header that’s not  
> > included in the free version of VC++. I’ll have to ask around.
> 
> > Thanks,
> 
> > Dan
> 
> Seems OMP is included in standard and up.[http://members.gamedev.net/Rivorus/surge/html/surge\_act/setting\_up\_yo](http://members.gamedev.net/Rivorus/surge/html/surge_act/setting_up_yo)…

Drat.

> If you send me the patch/instructions I can compile that for you.

Edit array.c and add the rb\_ary\_acollect function in my OP anywhere  
above the Init\_array() declaration. Add “rb\_define\_method(rb\_cArray,  
“acollect”, rb\_ary\_acollect, 0);” where all the other method  
defintions are (near the bottom). Then recompile and install.

Thanks,

Dan

---

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**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 12, 2007, 11:02pm UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/5 "2007-03-12T23:02:56Z")

</div>

On 3/12/07, Daniel B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Edit array.c and add the rb\_ary\_acollect function in my OP anywhere  
> above the Init\_array() declaration. Add “rb\_define\_method(rb\_cArray,  
> “acollect”, rb\_ary\_acollect, 0);” where all the other method  
> defintions are (near the bottom). Then recompile and install.
> 
> Thanks,
> 
> Dan

Hi,

as I wasn’t able to compile 1.8.5-p12 I used the brand new 1.8.6 and  
VS 2005 SP1, XP SP2.

Patch to array.c is included and I added -openmp to CPPFLAGS.

First run as you posted in the original post:

W:\projects\ruby\ruby\ruby-1.8.6\win32\>bench\_collect.rb  
user system total  
real  
Array#collect 11.422000 0.094000 11.516000 (  
11.531000)  
Array#acollect  
W:/projects/ruby/ruby/ruby-1.8.6/win32/bench\_collect.rb:17:in  
`initialize': exception reentered (fatal) from W:/projects/ruby/ruby/ruby-1.8.6/win32/bench_collect.rb:17 from W:/projects/ruby/ruby/ruby-1.8.6/win32/bench_collect.rb:17:in `acollect’  
from W:/projects/ruby/ruby/ruby-1.8.6/win32/bench\_collect.rb:17  
from  
W:/projects/ruby/ruby/ruby-1.8.6/win32/bench\_collect.rb:17:in  
`times' from W:/projects/ruby/ruby/ruby-1.8.6/win32/bench_collect.rb:17 from c:/ruby/lib/ruby/1.8/benchmark.rb:293:in `measure’  
from c:/ruby/lib/ruby/1.8/benchmark.rb:377:in `report' from W:/projects/ruby/ruby/ruby-1.8.6/win32/bench_collect.rb:16 from c:/ruby/lib/ruby/1.8/benchmark.rb:177:in `benchmark’  
from c:/ruby/lib/ruby/1.8/benchmark.rb:207:in `bm’  
from W:/projects/ruby/ruby/ruby-1.8.6/win32/bench\_collect.rb:12

Second run without assignments:

W:\projects\ruby\ruby\ruby-1.8.6\win32\>bench\_collect.rb  
user system total  
real  
Array#collect 6.875000 0.047000 6.922000 (  
6.953000)  
Array#acollect  
W:/projects/ruby/ruby/ruby-1.8.6/win32/bench\_collect.rb:17: [BUG]  
cross-thread violation on rb\_thread\_schedule()  
ruby 1.8.6 (2007-03-13) [i386-mswin32\_80]

This application has requested the Runtime to terminate it in an unusual  
way.  
Please contact the application’s support team for more information.\>

---

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**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 12, 2007, 10:53am UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/6 "2007-03-12T10:53:03Z")

</div>

On 3/12/07, Daniel B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > > Just for kicks I tried creating a parallel Array#collect method, which  
> > > return rb\_ary\_new4(RARRAY(ary)-\>len, RARRAY(ary)-\>ptr);  
> > > rb\_define\_method(rb\_cArray, “acollect”, rb\_ary\_acollect, 0);
> > 
> > > Ideas?  
> > > 1.[Microsoft Learn: Build skills that open doors in your career](http://msdn2.microsoft.com/en-us/library/fw509c3b(VS.80).aspxsays)
> 
> Thanks,
> 
> Dan

Seems OMP is included in standard and up.  
[http://members.gamedev.net/Rivorus/surge/html/surge\_act/setting\_up\_your\_compiler.html](http://members.gamedev.net/Rivorus/surge/html/surge_act/setting_up_your_compiler.html)

If you send me the patch/instructions I can compile that for you.

Jano

---

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**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 13, 2007, 12:01am UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/7 "2007-03-13T00:01:10Z")

</div>

On Mar 12, 4:02 pm, “Jan S.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Hi,
> 
> as I wasn’t able to compile 1.8.5-p12 I used the brand new 1.8.6 and  
> VS 2005 SP1, XP SP2.
> 
> Patch to array.c is included and I added -openmp to CPPFLAGS.

> Second run without assignments:
> 
> W:\projects\ruby\ruby\ruby-1.8.6\win32\>bench\_collect.rb  
> user system total real  
> Array#collect 6.875000 0.047000 6.922000 ( 6.953000)  
> Array#acollect  
> W:/projects/ruby/ruby/ruby-1.8.6/win32/bench\_collect.rb:17: [BUG]  
> cross-thread violation on rb\_thread\_schedule()  
> ruby 1.8.6 (2007-03-13) [i386-mswin32\_80]

Ouch. I had a feeling it would collapse. Maybe wrapping the relevant  
code in RUBY\_CRITICAL would work, but that may defeat the purpose,  
assuming it even works at all.

Oh, well. It was fun to try at least. 🙂

Thanks,

Dan

---

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**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 13, 2007, 12:19am UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/8 "2007-03-13T00:19:37Z")

</div>

On 3/13/07, Daniel B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > > Dan  
> > > Second run without assignments:  
> > > code in RUBY\_CRITICAL would work, but that may defeat the purpose,  
> > > assuming it even works at all.
> 
> Oh, well. It was fun to try at least. 🙂
> 
> Thanks,
> 
> Dan

I have tried with 1.9 as well. It crashed in an even more interesting  
way – two pages of hex numbers, see below.

So the result is when ruby will be able to handle threads, this could  
be a way to speed it up. So far it goes faster down 😉

Jano

```
                                user system total 

```

## real Array#collect 2.515000 0.031000 2.546000 ( 2.546000) Array#acollect – stack frame ------------ 0000 (00BD0020): 00000004 0001 (00BD0024): 00000005 0002 (00BD0028): 00b5f70c 0003 (00BD002C): 00000004 0004 (00BD0030): 00b5f6e4 0005 (00BD0034): 00b60738 0006 (00BD0038): 0000003d 0007 (00BD003C): 00b5f6f8 0008 (00BD0040): 00b5f6d0 0009 (00BD0044): 00000004 0010 (00BD0048): 00ba5049 0011 (00BD004C): 00000004 0012 (00BD0050): 00b5f694 0013 (00BD0054): 0000003d 0014 (00BD0058): 00b5feb4 0015 (00BD005C): 00b5f680 0016 (00BD0060): 00000000 0017 (00BD0064): 00000004 0018 (00BD0068): 00000004 0019 (00BD006C): 00ba5049 0020 (00BD0070): 00b5f66c 0021 (00BD0074): 00b5f630 0022 (00BD0078): 00b5f66c 0023 (00BD007C): 00b4bc20 0024 (00BD0080): 00b4bc0c 0025 (00BD0084): 00b4bbf8 0026 (00BD0088): 00000004 0027 (00BD008C): 00000004 0028 (00BD0090): 00baa369 0029 (00BD0094): 00b60738 0030 (00BD0098): 00b4bbd0 0031 (00BD009C): 00b4bb58 0032 (00BD00A0): 00b4bb08 0033 (00BD00A4): 00000004 0034 (00BD00A8): 00000004 0035 (00BD00AC): 00000004 0036 (00BD00B0): 00baa369 0037 (00BD00B4): 00ba51bd 0038 (00BD00B8): 00001f41 0039 (00BD00BC): 00000004 0040 (00BD00C0): 00c4fdf5 0041 (00BD00C4): 00000004 0042 (00BD00C8): 00c4fdf5 0043 (00BD00CC): 00bd00b5 (= 37) 0044 (00BD00D0): 00b5f70c 0045 (00BD00D4): 00000004 0046 (00BD00D8): 00c4fd35 0047 (00BD00DC): 00000004 0048 (00BD00E0): 00c4fd35 0049 (00BD00E4): 00000231 0050 (00BD00E8): 00000231 0051 (00BD00EC): 00000004 0052 (00BD00F0): 00000001 ← lfp ← dfp – control frame ---------- c:0015 p:---- s:0053 b:0053 l:000052 d:000052 CFUNC :initialize c:0014 p:---- s:0051 b:0053 l:000052 d:000052 CFUNC :new c:0013 p:---- s:0047 b:0047 l:000046 d:000046 CFUNC :acollect c:0012 p:0008 s:0044 b:0044 l:000000D8 d:000043 BLOCK bench\_collect.rb:17 c:0011 p:---- s:0043 b:0043 l:000042 d:000042 FINISH c:0010 p:---- s:0041 b:0041 l:000040 d:000040 CFUNC :times c:0009 p:0013 s:0038 b:0038 l:000000D8 d:000037 BLOCK bench\_collect.rb:17 c:0008 p:0037 s:0037 b:0037 l:000036 d:000036 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:293 c:0007 p:0037 s:0029 b:0029 l:000028 d:000028 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:377 c:0006 p:0023 s:0022 b:0022 l:000000D8 d:0000026C BLOCK bench\_collect.rb:16 c:0005 p:0134 s:0020 b:0020 l:000019 d:000019 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:177 c:0004 p:0037 s:0011 b:0011 l:000010 d:000010 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:207 c:0003 p:0048 s:0005 b:0005 l:000000D8 d:000000D8 TOP bench\_collect.rb:12 c:0002 p:---- s:0002 b:0002 l:000001 d:000001 FINISH c:0001 p:---- s:0000 b:-001 l:000000 d:000000 ------

## – stack frame ------------ – control frame ---------- c:0019 p:---- s:-3096584 b:-001 l:00000000 d:00000000 ------ c:0018 p:---- s:-3096584 b:-001 l:00000000 d:00000000 ------ c:0017 p:---- s:-3096584 b:-001 l:00000000 d:00000000 ------ c:0016 p:---- s:-3096584 b:-001 l:00000000 d:00000000 ------ c:0015 p:---- s:0053 b:0053 l:000052 d:000052 CFUNC :initialize c:0014 p:---- s:0051 b:0053 l:000052 d:000052 CFUNC :new c:0013 p:---- s:0047 b:0047 l:000046 d:000046 CFUNC :acollect c:0012 p:0008 s:0044 b:0044 l:000000D8 d:000043 BLOCK bench\_collect.rb:17 c:0011 p:---- s:0043 b:0043 l:000042 d:000042 FINISH c:0010 p:---- s:0041 b:0041 l:000040 d:000040 CFUNC :times c:0009 p:0013 s:0038 b:0038 l:000000D8 d:000037 BLOCK bench\_collect.rb:17 c:0008 p:0037 s:0037 b:0037 l:000036 d:000036 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:293 c:0007 p:0037 s:0029 b:0029 l:000028 d:000028 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:377 c:0006 p:0023 s:0022 b:0022 l:000000D8 d:0000026C BLOCK bench\_collect.rb:16 c:0005 p:0134 s:0020 b:0020 l:000019 d:000019 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:177 c:0004 p:0037 s:0011 b:0011 l:000010 d:000010 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:207 c:0003 p:0048 s:0005 b:0005 l:000000D8 d:000000D8 TOP bench\_collect.rb:12 c:0002 p:---- s:0002 b:0002 l:000001 d:000001 FINISH c:0001 p:---- s:0000 b:-001 l:000000 d:000000 ------

## – stack frame ------------ 0000 (00BD0020): 00000004 0001 (00BD0024): 00000005 0002 (00BD0028): 00b5f70c 0003 (00BD002C): 00000004 0004 (00BD0030): 00b5f6e4 0005 (00BD0034): 00b60738 0006 (00BD0038): 0000003d 0007 (00BD003C): 00b5f6f8 0008 (00BD0040): 00b5f6d0 0009 (00BD0044): 00000004 0010 (00BD0048): 00ba5049 0011 (00BD004C): 00000004 0012 (00BD0050): 00b5f694 0013 (00BD0054): 0000003d 0014 (00BD0058): 00b5feb4 0015 (00BD005C): 00b5f680 0016 (00BD0060): 00000000 0017 (00BD0064): 00000004 0018 (00BD0068): 00000004 0019 (00BD006C): 00ba5049 0020 (00BD0070): 00b5f66c 0021 (00BD0074): 00b5f630 0022 (00BD0078): 00b5f66c 0023 (00BD007C): 00b4bc20 0024 (00BD0080): 00b4bc0c 0025 (00BD0084): 00b4bbf8 0026 (00BD0088): 00000004 0027 (00BD008C): 00000004 0028 (00BD0090): 00baa369 0029 (00BD0094): 00b60738 0030 (00BD0098): 00b4bbd0 0031 (00BD009C): 00b4bb58 0032 (00BD00A0): 00b4bb08 0033 (00BD00A4): 00000004 0034 (00BD00A8): 00000004 0035 (00BD00AC): 00000004 0036 (00BD00B0): 00baa369 0037 (00BD00B4): 00ba51bd 0038 (00BD00B8): 00001f41 0039 (00BD00BC): 00000004 0040 (00BD00C0): 00c4fdf5 0041 (00BD00C4): 00000004 0042 (00BD00C8): 00c4fdf5 0043 (00BD00CC): 00bd00b5 (= 37) 0044 (00BD00D0): 00b5f70c 0045 (00BD00D4): 00000004 0046 (00BD00D8): 00c4fd35 0047 (00BD00DC): 00000004 0048 (00BD00E0): 00c4fd35 0049 (00BD00E4): 00000231 0050 (00BD00E8): 00000231 – control frame ---------- c:0014 p:---- s:0051 b:0053 l:000052 d:000052 CFUNC :new c:0013 p:---- s:0047 b:0047 l:000046 d:000046 CFUNC :acollect c:0012 p:0008 s:0044 b:0044 l:000000D8 d:000043 BLOCK bench\_collect.rb:17 c:0011 p:---- s:0043 b:0043 l:000042 d:000042 FINISH c:0010 p:---- s:0041 b:0041 l:000040 d:000040 CFUNC :times c:0009 p:0013 s:0038 b:0038 l:000000D8 d:000037 BLOCK bench\_collect.rb:17 c:0008 p:0037 s:0037 b:0037 l:000036 d:000036 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:293 c:0007 p:0037 s:0029 b:0029 l:000028 d:000028 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:377 c:0006 p:0023 s:0022 b:0022 l:000000D8 d:0000026C BLOCK bench\_collect.rb:16 c:0005 p:0134 s:0020 b:0020 l:000019 d:000019 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:177 c:0004 p:0037 s:0011 b:0011 l:000010 d:000010 METHOD c:/ruby19/usr/lib/ruby/1.9/ benchmark.rb:207 c:0003 p:0048 s:0005 b:0005 l:000000D8 d:000000D8 TOP bench\_collect.rb:12 c:0002 p:---- s:0002 b:0002 l:000001 d:000001 FINISH c:0001 p:---- s:0000 b:-001 l:000000 d:000000 ------

DBG\> : “bench\_collect.rb:17:in `acollect'" DBG> : "bench_collect.rb:17:in `block (3 levels) in '”  
DBG\> : “bench\_collect.rb:17:in `times'" DBG> : "bench_collect.rb:17:in `block (2 levels) in '”  
DBG\> : “c:/ruby19/usr/lib/ruby/1.9/benchmark.rb:293:in `measure'" DBG> : "c:/ruby19/usr/lib/ruby/1.9/benchmark.rb:377:in `item’”  
DBG\> : “bench\_collect.rb:16:in `block in <main>'" DBG> : "c:/ruby19/usr/lib/ruby/1.9/benchmark.rb:177:in `benchmark’”  
DBG\> : “c:/ruby19/usr/lib/ruby/1.9/benchmark.rb:207:in `bm'" DBG> : "bench_collect.rb:12:in `'”  
[BUG] cfp consistency error - call0  
ruby 1.9.0 (2007-03-13) [i386-mswin32\_80]

This application has requested the Runtime to terminate it in an unusual  
way.  
Please contact the application’s support team for more information.

---

<div class="post-metadata">

**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [March 13, 2007, 1:33pm UTC](https://www.ruby-forum.com/t/trying-to-make-array-collect-massively-parallel-with-openmp/88479/9 "2007-03-13T13:33:05Z")

</div>

On 3/12/07, Daniel B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> On Mar 12, 4:02 pm, “Jan S.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Ouch. I had a feeling it would collapse. Maybe wrapping the relevant  
> code in RUBY\_CRITICAL would work, but that may defeat the purpose,  
> assuming it even works at all.

Even if it worked it would have some other problems. If the block  
argument was at all sensitive to evaluation order, for example, the  
results would be indeterminate I think.

For a cooked up example:

i = 0  
(1…100).to\_a.acollect {|elem| i += 1}

Interaction with the GC might also be interesting.

–  
Rick DeNatale

My blog on Ruby  
[http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/)