Welcome to Adams/Solver Subroutines - Kxcad.net

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Adams/Solver
npar An integer variable that indicates the number of constants you specify in the
USER parenthetical list. The primary purpose of the npar argument is to
provide VTOSUB with the number of values stored in the par array.
dflag A logical variable that Adams/Solver sets to true when it calls VTOSUB to
evaluate the partial derivatives of the specified functions. Otherwise,
Adams/Solver sets the dflag argument to false.
iflag A logical variable that Adams/Solver sets to true when it needs the functional
dependency of the user-defined expressions. You set functional
dependencies with the same calls to the SYSARY and SYSFNC utility
subroutines that are made to compute the values of the user-defined
expressions (see SYSARY and SYSFNC). If the iflag argument is false, the
values of the user-defined expressions are computed.
Output Arguments
result A double-precision array of length 3 that returns the x-, y-, and z-components
of the VTORQUE.
Extended Definition
You can often use the VTORQUE statement with function expressions sufficient to define the three
rotational vector components of a torque at a point. However, if the torque expressions become lengthy
and awkward, you can use a VTOSUB evaluation subroutine. If the algorithms use or consist of already
existing FORTRAN-77 subroutines, VTOSUB can be made to call them.
You can call utility subroutines, such as AKISPL, CUBSPL, SYSARY and SYSFNC, from VTOSUB to
obtain information about system variables, user-defined variables, and splines. See AKISPL, CUBSPL,
SYSARY, and SYSFNC.
The SYSARY and SYSFNC utility subroutines automatically set functional dependencies when the
VTOSUB argument iflag is true. In order for Adams/Solver to compute solutions efficiently, it must
know on which other variables each user-defined variable depends directly. Adams/Solver determines
these functional dependencies at the beginning of the simulation by calling VTOSUB with the argument
iflag set to true. Adams/Solver does this once for each VTORQUE statement with a
FUNCTION=USER() argument.
During each call to the VTOSUB evaluation subroutine, Adams/Solver records which calls you make to
SYSARY and SYSFNC and assumes that the resulting values are dependent on only those Adams/Solver
variables accessed through the SYSARY and SYSFNC calls.
Tip: If the SYSARY or SYSFNC utility subroutines are called to access angular displacements,
the values returned by these may contain discontinuities. To avoid the discontinuities, use
the RCNVRT utility subroutine to convert the rotational angles from Euler angles to some
other coordinate system that does not encounter a singularity.