 
      AMOSLIB IS A COLLECTION OF PORTABLE FORTRAN ROUTINES FOR THE
EVALUATION OF SOME SPECIAL FUNCTIONS OF MATHEMATICAL PHYSICS.
      THE CURRENT CONTENTS OF AMOSLIB ARE:
       DPSIXN
        PSIXN
       DEXINT
        EXINT
        BESY
       DBESJ
       DPSIFN
        PSIFN
WHICH ARE BRIEFLY DESCRIBED BELOW.
 
      DOUBLE PRECISION FUNCTION DPSIXN(N)
C
C     THIS SUBROUTINE RETURNS VALUES OF PSI(X)=DERIVATIVE OF LOG
C     GAMMA(X), X.GT.0.0 AT INTEGER ARGUMENTS. A TABLE LOOK-UP IS
C     PERFORMED FOR N.LE.100, AND THE ASYMPTOTIC EXPANSION IS
C     EVALUATED FOR N.GT.100.
C
 
      SUBROUTINE EXINT(X, N, KODE, M, TOL, EN, IERR)
C
C     WRITTEN BY D.E. AMOS, SANDIA LABORATORIES, ALBUQUERQUE, NM, 87185
C
C     REFERENCE
C         COMPUTATION OF EXPONENTIAL INTEGRALS BY D.E. AMOS, ACM
C         TRANS. MATH SOFTWARE, 6, 1980
C
C     ABSTRACT
C         EXINT COMPUTES M MEMBER SEQUENCES OF EXPONENTIAL INTEGRALS
C         E(N+K,X), K=0,1,...,M-1 FOR N.GE.1 AND X.GE.0.  THE POWER
 
      FUNCTION PSIXN(N)
C
C     THIS SUBROUTINE RETURNS VALUES OF PSI(X)=DERIVATIVE OF LOG
C     GAMMA(X), X.GT.0.0 AT INTEGER ARGUMENTS. A TABLE LOOK-UP IS
C     PERFORMED FOR N.LE.100, AND THE ASYMPTOTIC EXPANSION IS
C     EVALUATED FOR N.GT.100.
C
 
      SUBROUTINE DEXINT(X, N, KODE, M, TOL, EN, IERR)
C
C     WRITTEN BY D.E. AMOS, SANDIA LABORATORIES, ALBUQUERQUE, NM, 87185
C
C     REFERENCE
C         COMPUTATION OF EXPONENTIAL INTEGRALS BY D.E. AMOS, ACM
C         TRANS. MATH SOFTWARE, 1980
C
C     ABSTRACT      *** A DOUBLE PRECISION ROUTINE ***
C         DEXINT COMPUTES M MEMBER SEQUENCES OF EXPONENTIAL INTEGRALS
C         E(N+K,X), K=0,1,...,M-1 FOR N.GE.1 AND X.GE.0.  THE POWER
 
      SUBROUTINE DPSIFN(X,N,KODE,M,ANS,NZ,IERR)
C***KEYWORDS  DERIVATIVES OF THE GAMMA FUNCTION,DOUBLE PRECISION,
C             GAMMA FUNCTION,POLYGAMMA FUNCTION,PSI FUNCTION
C***AUTHOR  AMOS, DONALD E., SANDIA NATIONAL LABORATORIES
C***PURPOSE  Compute derivatives of the PSI function.
C            (18 or fewer digits)
C***REFERENCES  HANDBOOK OF MATHEMATICAL FUNCTIONS, AMS 55, NATIONAL
C                 BUREAU OF STANDARDS BY M. ABRAMOWITZ AND I. A.
C                 STEGUN, 1964, PP.258-260, EQTNS. 6.3.5, 6.3.18, 6.4.6,
C                 6.4.9, 6.4.10
C               A PORTABLE FORTRAN SUBROUTINE FOR DERIVATIVES OF THE
C                 PSI FUNCTION BY D. E. AMOS, ACM TRANS. MATH SOFTWARE,
C                 1983, ALGORITHM 610
 
      SUBROUTINE PSIFN(X,N,KODE,M,ANS,NZ,IERR)
C***KEYWORDS  DERIVATIVES OF THE GAMMA FUNCTION,GAMMA FUNCTION,
C             POLYGAMMA FUNCTION,PSI FUNCTION
C***AUTHOR  AMOS, DONALD E., SANDIA NATIONAL LABORATORIES
C***PURPOSE  Compute derivatives of the PSI function.
C***DESCRIPTION
C
C         The following definitions are used in PSIFN:
C
C      Definition 1
C         PSI(X) = d/dx (ln(GAMMA(X)), the first derivative of
C                  the LOG GAMMA function.
C      Definition 2
C                     K   K
C         PSI(K,X) = d /dx (PSI(X)), the K-th derivative of PSI(X).
C***REFERENCES  HANDBOOK OF MATHEMATICAL FUNCTIONS, AMS 55, NATIONAL
C                 BUREAU OF STANDARDS BY M. ABRAMOWITZ AND I. A.
C                 STEGUN, 1964, PP.258-260, EQTNS. 6.3.5, 6.3.18, 6.4.6,
C                 6.4.9, 6.4.10
C               A PORTABLE FORTRAN SUBROUTINE FOR DERIVATIVES OF THE
C                 PSI FUNCTION BY D. E. AMOS, ACM TRANS. MATH SOFTWARE,
C                 1983, ALGORITHM 610
 
      SUBROUTINE BESY(X,FNU,N,Y)
C***KEYWORDS  BESSEL FUNCTION,SPECIAL FUNCTION,Y BESSEL FUNCTION
C***AUTHOR  AMOS, D. E., (Sandia National Laboratories, Albuquerque)
C***PURPOSE  BESY implements forward recursion on the three term recur-
C            sion relation for a sequence of non-negative order Bessel
C            functions Y/SUB(FNU+I-1)/(X), I=1,N for real X.GT.0.0E0 and
C            non-negative orders FNU.
 
      SUBROUTINE DBESJ(X,ALPHA,N,Y,NZ)
C***KEYWORDS  BESSEL FUNCTION,DOUBLE PRECISION,J BESSEL FUNCTION,
C             SPECIAL FUNCTION
C***AUTHOR  AMOS, D. E., (Sandia National Laboratories, Albuquerque)
C           DANIEL, S. L., (Sandia National Laboratories, Albuquerque)
C           WESTON, M. K., (Sandia National Laboratories, Albuquerque)
C***PURPOSE  Compute an N member sequence of J Bessel functions
C            J/SUB(ALPHA+K-1)/(X), K=1,...,N for non-negative ALPHA
C            and X. (At most 14 digits.)
C***REFERENCES  CDC 6600 SUBROUTINES IBESS AND JBESS FOR BESSEL
C                 FUNCTIONS I(NU,X) AND J(NU,X), X .GE. 0, NU .GE. 0,
C                 BY D. E. AMOS, S. L.DANIEL, M. K. WESTON,  ACM
C                 TRANSACTIONS ON MATHEMATICALSOFTWARE, VOL. 3,
C                 PP. 76-92 (1977).
 
 
