ADAS Subroutine ass

C
       subroutine ass(a10,a1,a20,a2,phi1,phi2,x,n,e1,e2,nmax,rem)       
c-----------------------------------------------------------------------
c
c  ****************** fortran77 subroutine: ass   **********************
c
c  purpose:  calculates asymptotic integrals using power series modules 
c
c
c  subroutine:
c
c  input : (r*8)  a10
c  input : (r*8)  a1
c  input : (r*8)  a20
c  input : (r*8)  a2
c  input : (r*8)  phi1
c  input : (r*8)  phi2
c  input : (r*8)  x
c  input : (i*4)  n
c  input : (r*8)  e1
c  input : (r*8)  e2
c  input : (i*4)  nmax
c
c  output: (r*8)  rem
c
c
c  routines:
c          routine    source    brief description
c          -------------------------------------------------------------
c          dnaq       adas      
c          dnprod     adas      
c          i4unit     adas      fetch unit number for output of messages
c
c  author:  h. p. summers, university of strathclyde
c           ja7.08
c           tel. 0141-548-4196
c
c  date:    06/06/02
c
c  update:  

C VERSION: 1.1                          DATE: 04-07-96
C MODIFIED: WILLIAM OSBORN
C               - FIRST VERSION.
C VERSION: 1.2                          DATE: 19-12-01
C MODIFIED: Martin O'MULLANE
C               - Removed junk from > column 72.
C
C VERSION: 1.3                          DATE: 18-03-03
C MODIFIED: Hugh Summers
C               - re-written and documented
c
c-----------------------------------------------------------------------
c-----------------------------------------------------------------------
      INTEGER             N,           NMAX
      REAL*8              A1(20),      A10,         A2(20),      A20
      REAL*8              E1,          E2,          PHI1,        PHI2
      REAL*8              REM,         X