Approx for F, t tables -- Report



               Library of Routines for Cumulative Distribution
                 Functions, Inverses, and Other Parameters
                                 C and Fortran

                                 Barry W. Brown
                                  James Lovato
                                  Kathy Russell



     DCDFLIB (Double precision Cumulative Distribution Function LIBrary) is
     a  collection  of  routines  that   calculate cumulative  distribution
     functions,  inverses,   and   parameters   for   common    statistical
     distributions.  DCDFLIB uses published algorithms where available, and
     literature citations are included in the documentation.

     Values associated with a statistical distribution include X, the upper
     limit  of integration of the density,   P, the cumulative distribution
     function evaluated  at X, and auxillary parameters  such as degrees of
     freedom.   Given  all but  one such value,  a   routine in cdflib will
     calculate  the one value.  (CAVEAT:  For the central and noncentral F,
     the cdf is  sometimes  not monotone in  the  degrees of freedom.   For
     these  parameters, there can    be two  answers.   DCDFLIB  finds   an
     arbitrary one of the two in this case.

     Routines are provided for the following distributions.

         (1) Beta
         (2) Binomial
         (3) Chi-square
         (4) Noncentral Chi-square
         (5) F
         (6) Noncentral F
         (7) Gamma
         (8) Negative Binomial
         (9) Normal
         (10) Poisson
         (11) Student's t

                                WHERE TO GET IT

     Software  written by members  of  the section  is freely available  to
     anyone.   Readers  with Internet access and  a  browser might note the
     following web site addresses:

          University of Texas M. D. Anderson Cancer Center Home Page:

                    Department of Biomathematics Home Page:

                              Available Software:

     Our code can also be obtained  by anonymous ftp to
     The index is on file ./pub/index.  The index  can be viewed by issuing
     the following Unix command:


                                HOW TO GET IT

     The source is in directory ./pub/source.  Relevent files are:

     dcdflib.c-1.0-tar.Z: Source in Ansi C plus documentation.
     dcdflib.f-1.0-tar.Z: Source in Fortran 77 plus documentation. Source in K&R C (old C) plus documentation.

     MSDOS versions are self-extracting files packaged with a licensed
     copy of PKZIP.

     ./msdos/dcdc10.exe: Source in ANSI C
     ./msdos/dcdf10.exe: Source in F77

                                       Barry W. Brown
                                       Department of Biomathematics,
                                            Box 237
                                       University of Texas M. D.
                                            Anderson Hospital
                                       1515 Holcombe Blvd
                                       Houston, TX 77030