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Messages - hjb2004

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General Discussion / Re: Multicollinearity
« on: September 10, 2018, 01:55:26 pm »
Dear Anthony,

Following up on Xiang-Jun's reply, you are correct that the Transfactivity program does not explicitly deal with collinearity. This should not be a problem when Transfactivity is used to infer TF activities for additional expression profiles using one more PSAMs generated by MatrixREDUCE, as the stepwise PSAM discovery implemented by MatrixREDUCE was explicitly designed to make the PSAMs distinct from each other. In other words, when AffinityProfile is used with a set of PSAMs discovered by MatrixREDUCE to create a matrix containing total affinities for each sequence (which is also the first step performed by Transfactivity), the columns of that matrix will be close to orthogonal. The value of the regression coefficients in a multi-PSAM linear regression will then be close those obtained in separate single-PSAM fits.

Things are potentially different, however, when Transfactivity is used with a set of PSAMs obtained from another source such as Jaspar. In that case, there is no guarantee that the columns of the affinity matrix created by AffinityProfile are independent of each other, and the behavior of the regression could indeed become unstable due to collinearity. We were dealing with exactly this situation in two of our lab’s previous papers. In one case, we implemented L2-penalized regression in R with a design matrix generated by AffinityProfile to deal with collinearity when inferring protein-level activities for a large number of yeast transcription factors (Lee et al., Mol Syst Biol 2010; In the second case, when we were doing the same for human transcription factors based on a collection of PWMs from Jaspar, we did some additional preprocessing on the design matrix in R as well (Lee et al., PNAS 2014;; see supplemental methods).

I hope this is useful.

Best regards,

General Discussion / Re: availability of FeatureREDUCE?
« on: July 18, 2018, 04:34:12 pm »
Hello PK,

The latest/only version of FeatureREDUCE is indeed still the 2015 version on GitHub:

You may also be interested in No Read Left Behind (NRLB), the latest algorithm from our lab:

Best regards,
Harmen Bussemaker

General Discussion / Re: Error when generating logos in PDF format
« on: November 15, 2017, 06:56:27 pm »
Hi Xiang-Jun,

PDF support seems important to keep, and removing the option "-dTextAlphaBits=4" from config/pkg_settings.cfg completely solved the problem for me for this format, so I can continue with what I was doing now.

However, I agree that it will be best to discontinue GIF support. On my Mac at least, "convert" is not installed by default, and indeed GIF generation with "-format=gif" does not work:

$ LogoGenerator -file=results/psam_001.xml -format=gif
sh: line 6: convert: command not found
system('gs -sOutputFile=- \
   -sDEVICE=png16m \
   -q -r96 -dSAFER -dBATCH -dNOPAUSE \
   ./temp_logo.eps \
   | convert png:- ./psam_001.gif
') returns nonzero (32512)

Thanks for the quick response!


General Discussion / Error when generating logos in PDF format
« on: November 15, 2017, 05:36:00 pm »
Hi Xiang-Jun,

When I run these commands:

cd examples/MatrixREDUCE/spellman-alpha
LogoGenerator -file=results/psam_001.xml -format=pdf

I get the following error:

GPL Ghostscript 9.19:

    Can't set GraphicsAlphaBits or TextAlphaBits with a vector device.
Unrecoverable error: rangecheck in .putdeviceprops
system('gs -sOutputFile=./psam_001.pdf \
   -sDEVICE=pdfwrite \
   -dPDFSETTINGS=/printer \
   -dEmbedAllFonts=true \
   -q -r96 -dTextAlphaBits=4 -dSAFER -dBATCH -dNOPAUSE \
') returns nonzero (65280)

The error seems to be triggered by the "-dTextAlphaBits=4" option. When I run "gs" manually without it, it work fine.

Seems that this is a known problem with more recent versions of "gs". I use version 9.19 on a Mac OS 10.11.6.


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Created and maintained by Dr. Xiang-Jun Lu [律祥俊]. See also and