Hi Philip,

Sorry to drag up an old thread, but I wondered if you had info about the 
effects on results of limiting Comet memory usage by using a large bin, vs 
using the 64-bit binary and small bin? 

We are primarily working with QExactive data here. I was thinking of adding 
Comet to our pipeline, and checking on the bin-size effect on results - but 
cheekily wondered if you or anyone else have any feeling for this?

Cheers,

Dave Trudgian


On Thursday, January 17, 2013 6:56:11 AM UTC-6, Philip Brownridge wrote:
>
> Hello Jimmy, thank you very much for your quick reply! You're completely 
> correct about the fragment bin value, when I ran Comet (thank you for name 
> guidance) using the LTQ settings it worked fine! When I ran it on the high 
> resolution settings with task mamager on, I saw that I was getting the 
> calloc error at about 2Gb of memory. I'm running Comet on a win7-64bit 
> machine with 24Gb of memory and the program is called comet-win32, please 
> could you tell me whether it would be possible to recompile Comet for win64 
> and perform larger searches? Sorry if this is a naive question, i'm very 
> much a beginner when it comes to code.
> thank you again,
> Philip    
>
> On Wednesday, 16 January 2013 19:55:58 UTC, Jimmy Eng wrote:
>>
>> Philip,
>>
>> I'm guessing you're specifying a small "fragment_bin_tol" value for the 
>> high-res ms/ms spectra.  This causes Comet (not all capitalized) to use a 
>> ton of memory and you're just running out of memory.
>>
>> On the following UWPR SEQUEST page, there's a table correlating a set of 
>> fragment_bin_tol settings vs. # input spectra vs. memory used:
>>
>> https://proteomicsresource.washington.edu/sequest_release/release_201201.php
>> These numbers apply to Comet as well.
>>
>> To address the problem, run smaller searches i.e. run Comet on a subset 
>> of your input spectra.  You can do this either with the "scan_range" 
>> parameter in the params file or simply invoke the searches such as
>>    comet yourfile.mzXML:1-3000
>>    comet yourfile.mzXML:3001-6000
>>    comet yourfile.mzXML:6001-9000
>>
>> Your going to get multiple outputs if you do this which will need to be 
>> handled.  Splitting searches and managing results is something that some 
>> script should do for you; some day I'll throw some simple windows and linux 
>> example scripts on the Comet website for users.
>>
>> Hopefully we'll have a workaround to address the memory use for these 
>> small fragment_bin_tol values in the semi-near future (thanks to Mike 
>> Hoopmann here who has implemented sparse matrix support in the code which 
>> I'm actively working with now).
>>
>> - Jimmy
>>
>>
>> On Wed, Jan 16, 2013 at 11:05 AM, Philip Brownridge <
>> [email protected]> wrote:
>>
>>> Hello all, please can I apologise if I have posted this in the wrong 
>>> group, but I can't find a COMET group and there are other COMET postings 
>>> here so I hope someone can help me! I'm trying to use some QExactive data 
>>> with Comet and I keep getting either a calloc error message or a message 
>>> saying there is no search to perform. I can get COMET searches to work on 
>>> LTQ Orbitrap data but not QExactive. I have been using Proteowizard to 
>>> convert the RAW files to mzML. I'm using the default params file with high 
>>> resolution fragment ion parameters. 
>>> Please if anybody is using COMET with QExactive data please could they 
>>> let me know where i'm wrong!
>>> thanks in advance,
>>> Philip
>>>
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>>
>>

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