Thank you both for the fast responses,
Grigory, that is a really interesting paper. It does analyse the same
phenomena I'm interested in, but their focus is in localizing particles
that belong to the same class and have been separated, while my focus is
to find particles that belong nowhere and have been aimlessly shifting
classes. Anyway, their approach to merging classes seems quite useful.
As you say, particles may jump between similar classes, and currently I
try to take this into account by giving a intermediate score to those
particles that travel frequently between the same few classes, but
actually merging the classes might be a better approach. I believe I
will either try to mimic their scrip in bash and add it to mine (with a
proper authorship mention) or ask our IT team whether it would be
possible to get matlab installed in my computer.
Reza, you are right about Sparx, is a quite versatile software. Sadly,
our cluster seems to not like it so much, and we have some serious
problems running some of the programs included, mainly when using MPI.
I'm running a small test, but this far sxisac seems to run only using
one cpu, so I expect it will take quite long to finish. Our IT team is
working on this, but currently is not possible for me to use it
efficiently. Still, knowing that this program does this is helpful, I
can go into the files and related papers and try to find the criteria
they use.
Thanks again for your helpful comments,
Best regards,
Jesus
On 2016-06-01 14:10, Reza Khayat wrote:
> Hi,
>
> ISAC does what you’re seeking and a lot more. It’s in the Sparx
> package.
>
> Best wishes,
> Reza
>
> Reza Khayat, PhD
>
> Assistant Professor
>
> Department of Chemistry
>
> City College of New York
>
> 85 Saint Nicholas Terrace, CDI 2.318
>
> New York, NY 10031
>
> http://www.khayatlab.org/ [1]
>
> 212-650-6070
>
> FROM: Collaborative Computational Project in Electron cryo-Microscopy
> [mailto:[log in to unmask]] ON BEHALF OF Grigory Sharov
> SENT: Wednesday, June 01, 2016 7:58 AM
> TO: [log in to unmask]
> SUBJECT: Re: [ccpem] Stability of particles in Relion
> classifications
>
>
> Hi Jesus,
>
> you might look into this [2] paper from Frank's group. The matlab
> script described there should work (after few modifications) for the
> latest Relion version.
>
> Another thing is that particles will keep jumping if classes are very
> similar. You could look into ccpem archives about discussion on 3D
> classification convergence.
>
> Best regards,
> Grigory
>
>
> --------------------------------------------------------------------------------
>
>
> Grigory Sharov, Ph.D.
>
> Institute of Genetics and Molecular and Cellular Biology
> Integrated Structural Biology Department (CBI)
> 1, rue Laurent Fries
> 67404 Illkirch, France
>
> tel. 03 69 48 51 00
>
> e-mail: [log in to unmask] [3]
>
> On Wed, Jun 1, 2016 at 1:34 PM, Jesus GOMEZ <[log in to unmask] [4]>
> wrote:
>
>> Dear all,
>>
>> Currently I'm working with Relion and I find myself in the
>> following situation: In each iteration there is a percentage (around
>> 10-15% in the later iterations) of particles that changes classes.
>> What I don't know is if these particles are the same for all the
>> iterations or change every round of classification.
>>
>> To address this my idea is to classify my particles based on their
>> stability along the 2D or 3D classification, meaning that those
>> particles that change classes few times will be considered good, and
>> those changing many times will be considered bad and removed from
>> the dataset. Note that this is different from the "particle sorting"
>> option in Relion, which only takes into account the correlation
>> between each particle and the class it belongs to for one given
>> iteration (my idea is to combine these two types of classification
>> for a more complete cleaning of the dataset). This is not very
>> difficult technically, since the data needed is in the *data.star
>> files outputted by Relion. In fact I have written a very simple bash
>> application that reads the data and awards points to the particles
>> based on events such as "staying in the same class", "times stayed
>> in the same class in a row" and such, placing more weight in the
>> later iterations, which are more relevant in my opinion.
>>
>> My question is: does anyone use or know about something similar?
>> I'm looking for a solution for Relion, but any other program that
>> does this would also be welcome. Since I'm not a expert in this and
>> I'm using a quite simple and arbitrary approach to scoring the
>> particles I feel like there might already be a more established
>> solution for my problem that I have overlooked.
>>
>> Thank you in advance,
>>
>> Jesus Gomez de Segura
>
>
>
> Links:
> ------
> [1] http://www.khayatlab.org/
> [2] http://embl.fr/%20http:/dx.doi.org/10.1016/j.jsb.2014.10.006
> [3] mailto:[log in to unmask]
> [4] mailto:[log in to unmask]
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