Welcome to Adams/Solver Subroutines - Kxcad.net

114
Adams/Solver
DOUBLE PRECISION DX, VZ
INTEGER NUM, IPAR(2)
LOGICAL ERRFLG
LOGICAL PARFLG
CALL ADAMS_NEEDS_PARTIALS(PARFLG)
IPAR(1) = PAR(1)
IPAR(2) = PAR(2)
CALL SYSFNC('DX', IPAR, 2, DX, ERRFLG )
CALL SYSFNC('VZ', IPAR, 2, VZ, ERRFLG )
VALUE = DX*VZ
IF(PARFLG) THEN
CALL SYSPAR('DX', IPAR, 2, VZ, 1, ERRFLG)
CALL SYSPAR('VZ', IPAR, 2, DX, 1, ERRFLG)
ENDIF
CALL ERRMES(ERRFLG,'ERROR FOR SFORCE ',ID,'STOP')
RETURN
END
Using SYSPAR with Utility Subroutines
This SFOSUB example shows how you can use SYSPAR in conjunction with utility subroutines. In this
SFOSUB you have:
VALUE = -IMPACT(400-DM(12,9),-VR(12,9))
or, using the nomenclature developed earlier:
F = -IMPACT(400-M 1 ,-M 2 )
where M 1 = DM(12,9) and M 2 = VR(12,9). Here, you must rely on the ability of the IMPACT utility
function to provide partial derivatives of its arguments.
∂ F
----------
∂ M1 ∂ F
----------
∂ M2 =
=
∂ IMPACT
-------------------------- ( 400 – M
∂ M 1′ – M2) ( – 1)
1
∂ IMPACT
-------------------------- ( 400 – M
∂ M 1′ – M2) ( – 1)
2
The implementation follows. Pay close attention to the use of the IORD argument (argument 8) to the
IMPACT function. It controls whether 0th, 1st, or 2nd derivative of the impact is being requested. Learn
more about the IMPACT function (C++ or FORTRAN).