DIFF
The DIFF command redefines and/or lists the characteristics of a DIFF statement. The implicit/explicit nature of a DIFF element may not be changed, for example, the IMPLICIT option in the database may not be changed.
Format
Argument
 | Redefines an expression or redefines the list of constants passed to a user-written subroutine, for example, DIFSUB. |
IC=r1[,r2] | Redefines the value of the differential state. If you specify r2, the value of r2 will be used to start the computation of the derivative value of the differential state. |
STATIC_HOLD | Redefines the differential state to remain constant during static and quasi-static simulations. Notice the STATIC_HOLD argument may not be changed (once a differential state is defined as STATIC_HOLD, it will remain STATIC_HOLD for the rest of the simulation). |
DYNAMIC_HOLD | Redefines the differential state to remain constant during dynamic simulations. Notice the DYNAMIC_HOLD argument may not be changed (once a differential state is defined as DYNAMIC_HOLD, it will remain DYNAMIC_HOLD for the rest of the simulation). |
ROUTINE=libname::subname | Specifies an alternative library and name for the user subroutine DIFSUB. Learn more about the ROUTINE Argument. |
LIST | Lists the current values of the data defining the differential state. |
Extended Definition
The DIFF command allows you to list and/or modify the characteristics of a differential state. Adams Solver (C++) allows you to modify most of the characteristics set in the DIFF statement.
After changes to a DIFF element are processed, Adams Solver (C++) will also reprocess the numerical solutions to accommodate the changes set in this command.
Examples
DIFF/99, FUNCTION=-2*DIF(99) + SIN(TIME), LIST
DIFF/34, DYNAMIC_HOLD, LIST
See other available SIMULATE commands.