-
Notifications
You must be signed in to change notification settings - Fork 112
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
SegFault in Banded_SW when band_width is large #49
Comments
Dear Brett,
Thank you very much for sending me the error with data.
Currently, this SSW sometimes runs into problems when the penalties for
GapInit <= GapExtend. Biologically meaningful parameters should have
GapInit > GapExtend. Hope replacing GapInit=3 with GapInit=4 can work for
you.
I will look into the error anyway later, but it may take a long time.
Yours,
Mengyao
…On Tue, May 16, 2017 at 7:36 PM, Brett Bowman ***@***.***) < ***@***.***> wrote:
When aligning sequences of dissimilar size, I'm occasionally getting a
SegFault deep within "banded_sw". What appears to be happening is that the
initial boundary setting is finding a partially garbage (long
indel-containing) alignment in the larger sequence, creating a large size
discrepancy between sequences and large value for band_width going into
banded_sw, which breaks something deep in the aligner:
RefEnd,RefStart+1,RefLen,ReadEnd,ReadStart+1,ReadLen,BandWidth
759,1,760,5332,1483,3851,3092
Sample sequences are attached below. The alignment params used are:
Match=2; Mismatch=5; GapInit=3; GapExtend=3
problem_seqs.zip
<https://github.com/mengyao/Complete-Striped-Smith-Waterman-Library/files/1006117/problem_seqs.zip>
—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub
<#49>,
or mute the thread
<https://github.com/notifications/unsubscribe-auth/AAlVdLkbBPZDQsU81bl18IVhwEotW07vks5r6jMCgaJpZM4NdNEr>
.
|
Hi, I changed this to As I understand it, band_width > readLen doesn't make sense anyway so I think this is a reasonable fix. Corwin |
@corwinjoy Your suggestion also fixed my issue for when I assigned too small a (0) gap open penalty for long read / long reference. Is there a scenario where the band_width might possibly need to be larger, perhaps with some sort of indel in the read? |
I guess that is a good point. Your read might have dropped a number of bases so potentially the maximum band width might be bigger than your read. I would still apply this same fix and set the max to your readLen + some tolerance depending on the source of your reads. |
When aligning sequences of dissimilar size, I'm occasionally getting a SegFault deep within "banded_sw". What appears to be happening is that the initial boundary setting is finding a partially garbage (long indel-containing) alignment in the larger sequence, creating a large size discrepancy between sequences and large value for band_width going into banded_sw, which breaks something deep in the aligner:
RefEnd,RefStart+1,RefLen,ReadEnd,ReadStart+1,ReadLen,BandWidth
759,1,760,5332,1483,3851,3092
Sample sequences are attached below. The alignment params used are:
Match=2; Mismatch=5; GapInit=3; GapExtend=3
problem_seqs.zip
The text was updated successfully, but these errors were encountered: