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AcuSolve User-Defined Functions Manual
Customization of AcuSolve allowing you to customize certain capabilities of the solver.
Basic Routines
These routines are accessible by all user functions, and by external output codes.
udfSetSig()
Set a signal to alter the behavior of AcuSolve.

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AcuSolve is a leading general purpose CFD solver that is capable of solving the most demanding industrial and scientific applications.
Tutorials
Discover AcuSolve functionality with interactive tutorials.
AcuSolve Training Manual
Introduction of background knowledge regarding flow physics and CFD as well as detailed information about the use of AcuSolve and what specific options do.
AcuSolve Validation Manual
Collection of AcuSolve simulation cases for which results are compared against analytical or experimental results to demonstrate the accuracy of AcuSolve results.
AcuSolve Command Reference Manual
AcuSolve command descriptions and corresponding examples.
AcuSolve Programs Reference Manual
AcuSolve utility programs covering preparatory and post-processing as well as user-defined functions and utility scripts.
AcuSolve User-Defined Functions Manual
Customization of AcuSolve allowing you to customize certain capabilities of the solver.
- Input File
  To access a user-defined function in AcuSolve, you must reference it in the input file.
- Function Format
  A user-defined function has the following form (in C).
- Compile, Link and Run
  In order for the solver to access the user-defined functions, the functions must be compiled and linked into a shared library. The script acuMakeLib (for Linux) and acuMakeDll (for Windows) may be used for this purpose.
- Support Routines
  Within a user-defined function or an external output code data may be accessed through support routines. These routines provide flexibility, longevity, efficiency and the ability to check for run-time errors.
- Basic Routines
  These routines are accessible by all user functions, and by external output codes.
  - udfGetType()
    Get the type of the user-defined function.
  - udfGetProcld()
    Return the processor ID.
  - udfGetName()
    Return the user-given name of the input command associated with the user function.
  - udfCheckNumUsrVals()
    Check the number of user values given in the input file.
  - udfGetNumUsrVals()
    Return the number of user values supplied in the input file.
  - udfGetUsrVals()
    Return the array of user-supplied values.
  - udfCheckNumUsrStrs()
    Check the number of user strings given in the input file.
  - udfGetNumUsrStrs()
    Return the number of user strings supplied in the input file.
  - udfGetUsrStrs()
    Return the array of user supplied strings.
  - udfCheckNumUsrHists()
    Check the number of user history variables given in the input file.
  - udfGetNumUsrHists()
    Return the number of user history variables supplied in the input file.
  - udfGetUsrHistsCurr()
    Return the array of current history variables.
  - udfGetUsrHistsPrev()
    Return the array of history variables from the previous time step.
  - udfFirstCall()
    Determine whether this the first time a user-defined function is called.
  - udfFirstStep()
    Determine whether this is the initial time step of this run.
  - udfSetError()
    Print an error message and exit the solver.
  - udfPrintMess()
    Print a message to the standard output, or .log file, if active.
  - udfPrintMessPrim()
    Print a message to the standard output, or .log file, if active, for the primary processor/subdomain.
  - udfSetSig()
    Set a signal to alter the behavior of AcuSolve.
  - udfPrim()
    Determine whether this the primary processor/subdomain.
  - udfBcastVector()
    Broadcast a vector to all processors from the primary processor/subdomain.
  - udfSetUsrHandle()
    Save the handle (pointer) to user data for future retrieval.
  - udfGetUsrHandle()
    Return the handle (pointer) to previously saved user data.
- Client/Server Routines
  These routines are accessible only by multiplier function and mesh motion user functions.
- Global Routines
  These routines are accessible by all user functions, and by external output codes.
- Element Routines
  These routines are accessible only by the Body Force, Material Model and Component Model user functions, and by external output codes.
- Element Boundary Condition Routines
  These support routines are accessible only by the Element Boundary Condition user functions, and by external output codes.
- Nodal Boundary Condition Routines
  These support routines are accessible only by the Nodal Boundary Condition user functions.
- Nodal Initial Condition Routines
  These support routines are accessible only by the Nodal Initial Condition user functions.
- Periodic Boundary Condition Routines
  These support routines are accessible only by the Periodic Boundary Condition user functions.
- Subdomain Routines
  These support routines are accessible only within external output codes.
AcuTrace Command Reference Manual
Commands of AcuTrace, a particle tracer that runs as a post-processor to or a co-processor with AcuSolve.
AcuTrace User-Defined Functions Manual
Instructions to define additional solution quantities of AcuTrace called user equations.
AcuReport Reference Manual
Instruction of the AcuReport tool, a standalone post-processor batch tool used to generate a report from an AcuSolve solution database.
AcuSolve Surface Processing

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udfSetSig()

Set a signal to alter the behavior of AcuSolve.

Syntax

udfSetSig( udfHd, name, value ) ;

Type

AcuSolve User-Defined Function Basic

Parameters

udfHd

The opaque handle (pointer) which was passed to the user function.

name

integer

Symbolic name of the signal to be set

UDF_SIG_NO_CONV: Stagger not converged.
UDF_SIG_DONT_AMP_TIMEINC: Do not amplify time increment.
UDF_SIG_REDUCE_TIMEINC: Reduce time increment.
UDF_SIG_REDO_STEP: Redo time step.
UDF_SIG_MUST_REDO_STEP: Must redo time step.
UDF_SIG_FATAL: Fatal error, exit.
UDF_SIG_STOP: Stop at end of step.
UDF_SIG_OUTPUT: Output at end of step.
UDF_SIG_OUTPUT_RESIDUAL: Output nodal residual.
UDF_SIG_PARTIAL_UPDATE: Partially update solution.

value (real)

Value of the signal. Ignored except for UDF_SIG_PARTIAL_UPDATE name.

Return Value

None

Description

This routine allows you to send a signal to AcuSolve from a user-defined function. For example, to signal AcuSolve to stop at the end of the current time step:

udfSetSig( udfHd, UDF_SIG_STOP, 0 ) ;

Errors

This routine expects a valid udfHd.
name must be one of the supported names.