
View Poll Results: Do you use the breadthfirst mode of GMPECM?  
Yes, frequently  1  3.70%  
Rarely  6  22.22%  
(Almost) never  11  40.74%  
The WHAT?  9  33.33%  
Voters: 27. You may not vote on this poll 

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20110124, 12:47  #1 
"Nancy"
Aug 2002
Alexandria
2,467 Posts 
Do you use the breadthfirst mode of GMPECM?
Do you use the breadthfirst mode of GMPECM?

20110124, 13:12  #2 
Einyen
Dec 2003
Denmark
3037_{10} Posts 
You forgot the poll option "breadthfirst mode ???"
I had to read up on README to see what it was. 
20110124, 13:33  #3 
"Nancy"
Aug 2002
Alexandria
2,467 Posts 
If you consider yourself a regular GMPECM user and you've never heard of breadthfirst mode, please vote! I'm toying with the thought of removing it, mostly because I don't understand what our main() function does, and wonder how many users would miss it.

20110124, 13:45  #4  
Nov 2003
2^{2}·5·373 Posts 
Quote:
convolutions for products of (p_i  p_j) as p_i and p_j vary over (different) arithmetic sequences, one can fix p_i and let p_j vary or viceversa. I am guessing that one is referred to as depthfirst, and the other as breadthfirst. Is my guess close? 

20110124, 13:46  #5 
Mar 2010
3·137 Posts 
From the tarball's README:
Code:
NOTE that in b "breadthfirst" mode, GMPECM reads all candidate numbers in the input stream and keeps them in memory, so if there are many large numbers to be tested, the memory requirement will increase noticeably. 
20110124, 13:48  #6 
"Nancy"
Aug 2002
Alexandria
100110100011_{2} Posts 
Not remotely. Breadthfirst mode reads all input numbers into memory, then does one curve on each number in turn, up to the desired number of curves. May have a use if you want any one factor from a set of input numbers, but I don't seen much use beyond that. Most of its functionality could be replicated by a shell script that executes GMPECM repeatedly, doing one curve per input number per execution.

20110124, 14:16  #7  
Nov 2003
7460_{10} Posts 
Quote:
I agree that this feature does not seem all that useful. 

20110124, 15:20  #8 
Jun 2003
1001011111000_{2} Posts 
I've used it for brilliant number search.

20110124, 15:40  #9 
"Ben"
Feb 2007
3,371 Posts 
I've never used it, but why remove functionality if it works?

20110124, 17:06  #10 
"Nancy"
Aug 2002
Alexandria
2,467 Posts 
The main function is a mess of loops and gotos, I can't get it through my head. Every time I tried I was overcome by the thought "why can't I just bin this?"

20110124, 17:55  #11 
Sep 2009
2,003 Posts 
I've used it to avoid having both tasks on a dual core machine running stage 1 and stage 2 at the same time. By running 1 task depth first and 1 breadth first I can get them to process the numbers in a different order.
But I'm not sure if it gives any real speedup, even when the two tasks are on 1 CPU with hyperthreading. Chris K 
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