Re: [gecode-users] Counting clones

Fri, 01 Jun 2012 12:04:02 -0700

Hi Christian,

Thanks for the reply, I think I got it. I was under the impression that recomputation (and adaptive recomputation) where techniques for optimizing runtime performance when compared with standard copy since recomputing could perhaps be faster than copying for some cases. But now I see I was wrong and that their purpose is only to save space. This means that setting c_d=1  should always provide faster runtime than any other method (assuming that the problem at hand does not require huge amounts of memory). Am I getting the right picture now, or am I oversimplifying?

Thanks!
Marco
June 1, 2012 7:41 PM
Hi Marco,

Well, the number of clones _is_ the same for any value of c-d or a-d! You
have to backtrack, so you have to make a clone! The difference is that you
clone different spaces.

Christian

--
Christian Schulte, www.ict.kth.se/~cschulte/


-----Original Message-----
From: users-boun...@gecode.org [mailto:users-boun...@gecode.org] On
Behalf Of Marco Correia
Sent: Friday, June 01, 2012 6:54 PM
To: 'gecode list'
Subject: [gecode-users] Counting clones

Hi,

I suspect the answer to the following question should be somewhere in the

MPG

document, but I was unable to find it - apologies if this is the case.

I am interested on obtaining the number of clones for a specific example

when

subject to different value for the c_d parameter in the context of a DFS

search. I

believe gecode used to report this value in the statistics, but now it

seems there

is a specific class CloneStatistics which should be updated as search

proceeds. I

fail to see how to pass an object of type CloneStatistics to the DFS

search

object. Also the
Space::clone() member function (which seems to be the only place where

this

object can be updated) is not virtual, and therefore cannot be intercepted

in my

subclass of Space (is this correct?). So I tried another approach, which

was

simply to count the number of times that my
copy() function gets called, which I thought should tell me the number of

clones.

Now I think I'm wrong since this number always reports the same number of
clones for different values of c_d.

Obviously I'm making some mistake. Any hints?

Thanks!

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  June 1, 2012 5:53
 PM

  
Hi,



I suspect the answer to the following question should be somewhere 
in 
the MPG document, but I was unable to find it - apologies if this is the
 
case.



I am interested on obtaining the number of clones for a specific 
example 
when subject to different value for the c_d parameter in the context of 
a DFS search. I believe gecode used to report this value in the 
statistics, but now it seems there is a specific class CloneStatistics 
which should be updated as search proceeds. I fail to see how to pass an
 
object of type CloneStatistics to the DFS search object. Also the 
Space::clone() member function (which seems to be the only place where 
this object can be updated) is not virtual, and therefore cannot be 
intercepted in my subclass of Space (is this correct?). So I tried 
another approach, which was simply to count the number of times that my 
copy() function gets called, which I thought should tell me the number 
of clones. Now I think I'm wrong since this number always reports the 
same number of clones for different values of c_d.



Obviously I'm making some mistake. Any hints?



Thanks!


  
 	
      
   
  June 1, 2012 4:42
 PM

  
Hi,



I suspect the answer to the following question should be somewhere 
in 
the MPG document, but I was unable to find it - apologies if this is the
 
case.



I am interested on obtaining the number of clones for a specific 
example 
when subject to different value for the c_d parameter in the context of 
a DFS search. I believe gecode used to report this value in the 
statistics, but now it seems there is a specific class CloneStatistics 
which should be updated as search proceeds. I fail to see how to pass an
 
object of type CloneStatistics to the DFS search object. Also the 
Space::clone() member function (which seems to be the only place where 
this object can be updated) is not virtual, and therefore cannot be 
intercepted in my subclass of Space (is this correct?). So I tried 
another approach, which was simply to count the number of times that my 
copy() function gets called, which I thought should tell me the number 
of clones. Now I think I'm wrong since this number always reports the 
same number of clones for different values of c_d.



Obviously I'm making some mistake. Any hints?



Thanks!






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