I see that the mzML converter in the TPP offers the centroid option in
the Petunia interface. I assume this also uses Masswolf for
centroiding? At this point the masswolf centroid is my only real
option, except for converting the files to pkl, at which point I am
not sure if I can run them through the TPP, correct me if I am wrong
here.

Chris

On Jul 16, 10:52 am, Matthew Chambers
<[email protected]> wrote:
> The pwiz non-vendor centroiding currently available to msconvert is a
> very crude local maximum algorithm. But I have virtually no doubt that
> even using that crude algorithm would give better results with any
> centroid-dependent search engine than using the raw profile data.
> Whether it performs better than the masswolf centroiding... I have done
> no comparisons so I can't say. Pwiz also has Savitzky-Golay smoothing
> which is good to apply to spiky profile data before applying
> local-maximum peak picking, but it's not accessible from msconvert yet.
> It is accessible from SeeMS, which allows to adjust the SG window size
> and polynomial order and also the peak picker window size and
> immediately see the result.
>
> -Matt
>
> Natalie Tasman wrote:
> > Hi Chris,
>
> > Just a reminder that the masswolf centroid mode is experimental, as
> > noted in the "usage" statement.
>
> > Matt, how is PWIZ centroiding?  Can msconvert be used to apply this
> > signal processing and output a processed mzXML file?
>
> > -Natalie
>
> > On Wed, Jul 15, 2009 at 11:57 AM, Chris Hughes <[email protected]
> > <mailto:[email protected]>> wrote:
>
> >     Thanks Matt.
>
> >     That being said, I have a batch of profile data now that I will likely
> >     use the masswolf centroid option to deal with so I can search it in
> >     XTandem. Is there any way to batch process using Masswolf with the
> >     centroiding option? I notice its not part of the TPP.
>
> >     Chris
>
> >     On Jul 15, 2:46 pm, Matthew Chambers
> >     <[email protected]
> >     <mailto:[email protected]>>
> >     wrote:
> >     > Hi Chris,,
>
> >     > AFAIK, X! Tandem isn't designed to run on profile mode data. If
> >     you are
> >     > using the default "total peaks" setting then it will take only
> >     the 50
> >     > most intense samples (not peaks, because it assumes every data
> >     point is
> >     > a peak). 50 samples are easily consumed by just a few peaks. You can
> >     > increase the total peaks setting, but I expect that would kill
> >     the score
> >     > discrimination because it's designed to look at peaks instead of
> >     > samples. You should continue to acquire centroided MS/MS data or at
> >     > least have some way to centroid it post-acquisition before
> >     sending it to
> >     > X! Tandem.
>
> >     > -Matt
>
> >     > chr12is wrote:
> >     > > Greetings,
>
> >     > > I am encountering an error which I dont remember having
> >     troubles with
> >     > > before. I used to acquire my data such that in MS/MS mode it
> >     would be
> >     > > centroided, as in older versions of the TPP, filesizes over
> >     4gb were
> >     > > problematic. Since I have noticed this isnt a problem anymore
> >     in the
> >     > > newer TPP versions, I am using 4.2.1, I have started acquiring in
> >     > > continuum mode again for MS/MS. I have MassLynx 4.1 installed, and
> >     > > have run centroided MS/MS files through the TPP on this
> >     computer with
> >     > > no problems.
>
> >     > > However, if I take one of my new continuum files, it converts in
> >     > > masswolf with no errors, I am not centroiding in masswolf, or
> >     using
> >     > > gzip. When I take it to XTandem it gives me this error:
>
> >     > > X! TANDEM 2 (2007.07.01.3)
>
> >     > > Loading spectra ...
> >     > > This application has requested the Runtime to terminate it in an
> >     > > unusual way.
> >     > > Please contact the application's support team for more
> >     information.
>
> >     > > Any ideas whats happening?
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