Sherpa 1.3.0 and LHAPDF 5.8.5 (gzipped PDFs)

[Generic User (don't modify these fields)]

Dear Sherpa authors,

I face some problems handling gzipped PDFs from LHAPDF. I'm using Sherpa 1.3.0 and LHAPDF 5.8.5 from the CMSSW framework for a simple DY example:

...

(isr){

PDF_LIBRARY = LHAPDFSherpa

PDF_SET = cteq6ll.LHpdf

PDF_SET_VERSION = 1

PDF_GRID_PATH = PDFsets

}(isr)

...

Now when I run Sherpa, it claims that the PDF cannot be found:

...

Initialized the beams Monochromatic*Monochromatic Sherpa: Initialization_Handler::InitializeThePDFs throws critical error:

PDF 'cteq6ll.LHpdf' does not exist in 'libLHAPDFSherpa' for P+ bunch.

Exception_Handler::GenerateStackTrace(..): Generating stack trace {

0x2b70f7e52750 in 'ATOOLS::Terminate()' (Exception_Handler.C:132) 0x40383f in 'main' (atomicity.h:69)

}

...

However,

Sherpa PDF_LIBRARY=LHAPDFSherpa SHOW_PDF_SETS=1

reveals

...

available PDF sets (specified by PDF_SET=<value>)

...

cteq6ll.LHpdf.gz LHAPDF interface

...

Then I change the name of the PDF to xxxxxxx.gz

...

(isr){

PDF_LIBRARY = LHAPDFSherpa

PDF_SET = cteq6ll.LHpdf.gz

PDF_SET_VERSION = 1

PDF_GRID_PATH = PDFsets

}(isr)

...

and the following happens:

...

Initialized the beams Monochromatic*Monochromatic LHAPDF_Fortran_Interface::LHAPDF_Fortran_Interface(): Init member 1. GZIOOP: input file open error

LHAPDF InitPDFsetM : unable to open file /afs/cern.ch/cms/slc5_amd64_gcc434/external/lhapdf/5.8.5-cms2/share/lhapdf/PDFsets/cteq6ll.LHpdf.gz.gz

status = 108

...

Am I missing something here???

Cheers, Markus

[Frank Siegert]

Hi Markus,

I wasn't aware of LHAPDF being able to read gzipped LHpdf files. Is that a CMS specific change? In both cases: Why is LHAPDF adding another ".gz" to the end of the filename?

Cheers, Frank

[Frank Siegert]

This seems to be a CMS software specific issue. Closing it here.