ADAS Subroutine r8econ

      FUNCTION R8ECON( INTYP, OUTTYP, EIN )
C-----------------------------------------------------------------------
C
C  ****************** FORTRAN77 SUBROUTINE: R8ECON *********************
C
C  PURPOSE: TO CONVERT A VELOCITY/ENERGY INTO A SPECIFIED FORM
C
C           (DOUBLE PRECISION FUNCTION VERSION OF 'XXECON')
C
C  CALLING PROGRAM: GENERAL USE
C
C  FUNCTION:
C
C             (R*8)  R8ECON  = FUNCTION NAME -
C                              OUTPUT VELOCITY/ENERGY (STATED UNITS)
C             (I*4)  INTYP   = 1 => 'EIN' UNITS: AT. UNITS (VEL.)
C                            = 2 => 'EIN' UNITS: CM/SEC    (VEL.)
C                            = 3 => 'EIN' UNITS: EV/AMU  (ENERGY)
C             (I*4)  OUTTYP  = 1 => 'R8ECON' UNITS: AT.UNITS (VEL.)
C                            = 2 => 'R8ECON' UNITS: CM/SEC   (VEL.)
C                            = 3 => 'R8ECON' UNITS: EV/AMU (ENERGY)
C             (R*8)  EIN     = INPUT  VELOCITY/ENERGY (STATED UNITS)
C
C             (R*8)  AMU2KG  = PARAMETER: AMU TO KG CONVERSION FACTOR
C             (R*8)  EV2J    = PARAMETER: EV TO JOULES CONVERSION FACTOR
C             (R*8)  M2CM    = PARAMETER: METRES TO CM CONVERSION FACTOR
C             (R*8)  VELE0H  = PARAMETER: ORBITAL VELOCITY  (CM/SEC)  OF
C                              AN ELECTRON IN THE SMALLEST  ORBIT  OF  A
C                              HYDROGEN ATOM (BOHR) = 2.1877D+8 CM/SEC
C             (R*8)  AT2VEL  = AT.UNITS (VEL) TO CM/SEC (VEL) CONVERSION
C             (R*8)  VEL2AT  = CM/SEC (VEL) TO AT.UNITS (VEL) CONVERSION
C             (R*8)  VEL2EN  = CM/SEC (VEL) TO EV/AMU (ENGY.) CONVERSION
C             (R*8)  EN2VEL  = EV/AMU (ENGY.) TO CM/SEC (VEL) CONVERSION
C             (R*8)  AT2EN   = AT.UNITS (VEL) TO EV/AMU (ENG) CONVERSION
C             (R*8)  EN2AT   = EV/AMU (ENG) TO AT.UNITS (VEL) CONVERSION
C
C             (R*8)  ECONV() = ENERGY/VELOCITY CONVERSION PARAMETERS
C
C ROUTINES:  NONE
C
C NOTE:
C            ENERGY/VELOCITY CONVERSION PARAMETERS:
C
C            INTYP = 1 ; ECONV(1) =>  VELOCITY: AT.UNITS -> OUTPUT FORM
C            INTYP = 2 ; ECONV(2) =>  VELOCITY: CM/SEC   -> OUTPUT FORM
C            INTYP = 3 ; ECONV(3) =>  ENERGY  : EV/AMU   -> OUTPUT FORM
C
C AUTHOR:  PAUL E. BRIDEN (TESSELLA SUPPORT SERVICES PLC)
C          K1/0/81
C          JET EXT. 4569
C
C DATE:    05/02/91
C
C VERSION: 1.2				DATE: 01-05-96
C MODIFIED: WILLIIAM OSBORN (TESSELLA SUPPORT SERVICES PLC)
C	    - CORRECTED AT2EN. WAS AT2VEL*VEL2EN
C
C VERSION: 1.2                          DATE: 10-04-2007
C MODIFIED : Allan Whiteford
C               - Modified documentation as part of automated
C		  subroutine documentation preparation.
C
C-----------------------------------------------------------------------
C
C-----------------------------------------------------------------------
      INTEGER             INTYP,       OUTTYP
      REAL*8              EIN