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  Topic: Evolutionary Computation, Stuff that drives AEs nuts< Next Oldest | Next Newest >  

Posts: 13
Joined: June 2009

(Permalink) Posted: June 12 2009,10:58   

Jorge Fernandez at TWeb is in contact with Sanford.  He just posted the following from Sanford:

Hi Jorge - I have been traveling ... The comment ... about "cooking the books" is, of course, a false accusation. The issue has to do with memory limits. Before a Mendel run starts it allocates the memory needed for different tasks. With deleterious mutations this is straight-forward - the upper range of mutation count is known. With beneficials it is harder to guess final mutation count - some beneficials can be vastly amplified. Where there is a high rate of beneficials they can quickly exhaust RAM and the run crashes. Wesley Brewer [one of the creators of Mendel] has tried to avoid this by placing certain limits - but fixing this is a secondary priority and will not happen right away. With more RAM we can do bigger experiments. It is just a RAM issue.

Best - John

This is in response to - "Wes Elseberry made a comment that I think could be a good title, 'Mendel's Accountant
cooks the books."  I assume that they're talking about the failure of the program to increase fitness when a high number of beneficial mutations are specified.

I guess Sanford et al would argue that this problem isn't a big issue, since there's never a case in which there are loads (e.g. 90%) of beneficial mutations.  Deleterious or slightly deleterious are in the majority in reality, there's no RAM problem with these, and so the main conclusion they draw from Mendel is unaffacted by the problems shown with beneficial mutations.  At least I guess that's what he'd say.

Sanford also says:

The fact that our runs crash when we run out of RAM is not by design. If someone can help us solve this problem we would be very grateful. We typically need to track hundreds of millions of mutations. Beneficials create a problem for us because they amplify in number. We are doing the best we can.

I would urge your colleagues [Heaven help me - John is under the impression that you people are my colleagues ... brrrrrrrr!] to use more care. In science we should be slow to raise claims of fraud without first talking to the scientist in question to get their perspective. Otherwise one might unwittingly be engaging in character assassination.

  419 replies since Mar. 17 2009,11:00 < Next Oldest | Next Newest >  

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