On Wed, 2003-07-30 at 18:23, Majorinc, Kazimir wrote:
> I wrote the program that process graphs where each node is represented as
> record containing two lists of other nodes. It seems there is some problem
> with that concept. Here is the code that causes problem:
...
>
> Compile and executed (on 9.3.2 version of Icon for Windows or on Unicon for
> Windows - I think it is last version) it allocates ~37 000 nodes (records
> double_list) and then suddenly crushes. Although 37 000 might look good
> enough, it really isn't:
>
> with very simple changes, for example, 'every 1 to 1' instead "every 1 to
> 2" or deleting line "put(random_old_double...", program will happily
> allocate 566 000 objects (in both cases), and even then, it will not crush
> but hang attempting to write something on the disk, as typical for Windows.
> Anycase, that is satisfactory. Note that in both cases, circular references
> still exist, and even if "every 1 to 100" is used in combination with
> single list, program still allocates 100 000+ records before it hangs.
What a fascinating problem! I'm interested in seeing what the
explanation is...
I did a little instrumentation, using a slightly modified version
of the program, running with Unicon on Linux:
------------------------------------------------------------------
record double_list(sublist,superlist)
procedure main()
first_double_list:=double_list([],[])
List_of_lists:=[first_double_list]
every j := seq(0) do {
new_double_list:=double_list([],[])
#every 1 to 1 do
every 1 to 2 do
{ random_old_double_list := ?List_of_lists #
put(new_double_list.sublist, random_old_double_list)
put(random_old_double_list.superlist, new_double_list)
}
put(List_of_lists,new_double_list)
if j % 1000 = 0 then {
write ("First ",j," are OK.")
showSizes()
}
}
end
procedure showSizes()
local l1,l2
every put(l1 := [], &storage)
every put(l2 := [], ®ions)
write("\tstatic : ",l1[1],"/",l2[1])
write("\tstring : ",l1[2],"/",l2[2])
write("\tblock : ",l1[3],"/",l2[3])
end
-------------------------------------------------------------------------
With the code as above, the program ran through 118000+ iterations
before terminating (no error message, but with status 139 returned
[and running with Icon instead of Unicon produced a segmentation
fault at the same place.]) Last region sizes were:
First 118000 are OK.
static : 0/0
string : 0/500000
block : 31479876/31500000
replacing the 'every 1 to 2 do' with 'every 1 to 1 do' ran *at least*
1931000 iterations (long pause there for GC and I wasn't ready to
wait...). Region sizes at that point were:
First 1931000 are OK.
static : 0/0
string : 0/500000
block : 511406048/511500000
So it's clearly not a problem with running out of heap.
--
Steve Wampler <[EMAIL PROTECTED]>
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