PDFLIB - A LIBRARY OF ALL AVAILABLE PARTON DENSITY-FUNCTIONS OF THE NUCLEON, THE PION AND THE PHOTON AND THE CORRESPONDING ALPHA-S CALCULATIONS

This document describes an integrated package of parton density functions called PDFLIB, which has been added to the CERN Program library Pool W999 and is labelled as W5051. In this package all the different sets of parton density functions of the nucleon, the pion and the photon which are available today (about 100 different sets) have been put together. All these sets have been combined in a consistent way such that they all have similar calling sequences and no external data files have to be read in anymore. A default set has been prepared, although those preferring their own set or wanting to test a new one may do so within the package. The selection mode, the program parameters as well as the possibilities to modify the defaults and to control errors which occurred during execution are described. The package also offers a program to calculate the strong coupling constant alpha(s) to first or second order (default). The correct LAMBDA(QCD) associated to the selected set of structure functions and the number of allowed flavours with respect to the given Q2 is automatically used in the calculation. For those structure functions where the evolution has been performed to leading order only, an alpha(s) value fixed to first order is returned.