10.2.1. Programming

Currently, user subroutines are only supported in FORTRAN 77. Any subroutine that can be compiled with a FORTRAN 77 compiler on the target execution machine can be used. The user should be aware that some computers support different FORTRAN language extensions than others. (In the future, other languages such as FORTRAN 90, C, and C++ may be supported.)

User subroutine variable types must interface directly with the matching variable types used in the main Sierra/SM code. Thus, the FORTRAN 77 subroutines should use only integer, double precision, or character types for any data used in the interface or in any query function. Using the wrong data type may yield unpredictable results. The methods used to pass character types from Sierra/SM to FORTRAN user subroutines can be machine-dependent, but generally this functionality works well.

The basic structure for the user subroutine is as follows:

subroutine sub_name(call list)
    {declaration of variables}
    {retrieve parameters from Sierra/SM input file}
    {query Sierra/SM for information}
    {application-specific code
       .
       .
    }
    {write computed values}
END

In general, the user will begin the subroutine with variable declarations. After the variable declarations, the user can then query the Sierra/SM input file for parameters. Additional Sierra/SM information such as field variables or element topology can then be retrieved from Sierra/SM. Once the user has collected all the information for the application, the application-specific portion of the code can be written. After the application-specific code is complete, the user may store computed values.

Section 10.2.1.1 through Section 10.2.1.3 describe in detail the format for the interfaces to Sierra/SM that will allow the user to make the subroutine call, retrieve information from Sierra/SM, and write computed values. In these sections, mesh entities can be a node, an element face, or an element.

10.2.1.1. Subroutine Interface

The following interface is used for all user subroutines:

subroutine sub_name(int  num_objects,
                    int  num_values,
                    real evaluation_time,
                    int  object_ids[],
                    real output_values[],
                    int  output_flags[],
                    int  error_code)

The name of the user subroutine, sub_name, is selected by the user. Avoid names for the subroutine that are longer than 10 characters. This may cause build problems on some systems.

A detailed description of the input and output parameters is provided in Table Table 10.1 and Table Table 10.2.

Table 10.1 Subroutine Input Parameters
Input Parameter	Data Type	Parameter Description
num_objects	Integer	Number of input mesh entities. For example, if the subroutine is a node set subroutine, this would be the number of nodes on which the subroutine will operate.
num_values	Integer	Number of return values. This is the number of values per mesh entity.
evaluation_time	Real	Time at which the subroutine should be evaluated. This may vary slightly from the current analysis time. For example, in explicit dynamics analyses, velocities are evaluated one-half time step ahead.
object_ids (num_objects)	Integer	Array of mesh-entity identification numbers. The array has a length of num_objects. The input numbers are the global numbers of the input objects. The object identification numbers can be used to query information about a mesh entity.

Table 10.2 Subroutine Output Parameters
Output Parameter	Data Type	Parameter Description
output_values (num_values, num_objects)	Integer	Array of output values computed by the subroutine. The number of output values will be either the number of mesh entities or some multiple of the number of mesh entities. For example, if there were six nodes (num_objects equals 6) and one value was to be computed per node, the length of output_values would be 6. Similarly, if there were six nodes (num_objects equals 6) and three values were to be computed for each node (as for acceleration, which has X-, Y-, and Z-components), the length of output_values would be 18.
output_flags (num_objects)	Integer	Array of returned flags for each set of data values. When used, this array will generally have a length of num_objects. The usage of the flags depends on subroutine type; the flags are currently used only for element death and for kinematic boundary conditions. For the kinematic boundary conditions (displacement, velocity, acceleration) a flag of –1 means ignore the constraint, a flag of 0 means set the absolute constraint value, and a flag of 1 means set the constraint with direction and distance.
error_code	Integer	Error code returned by the user subroutine. A value of 0 indicates no errors. Any value other than zero is an error. If the return value is nonzero, Sierra/SM will report the error code and terminate the analysis.

10.2.1.2. Query Functions

Sierra/SM follows a design philosophy for user subroutines that a minimal amount of information should be passed through the call list. Additional information may be queried from within the subroutine. A user subroutine may query a wide variety of information from Sierra/SM.

10.2.1.2.1. Parameter Query

A number of user subroutine parameters may be set as described in Section 10.2.2.2.2. These subroutine parameters can be obtained from the Sierra/SM input file via the query functions listed below.

aupst_get_real_param(string var_name, real var_value,
                     int error_code)

aupst_get_integer_param(string var_name, int var_value,
                        int error_code)

aupst_get_string_param(string var_name, string var_value,
                       int error_code)

All three of these subroutine calls are tied to a corresponding “parameter” command line that will appear in the Sierra/SM input file. The parameter command lines are described in Section 10.2.2.2.2. These command lines are named based on the type of value they store, i.e., SUBROUTINE REAL PARAMETER, SUBROUTINE INTEGER PARAMETER, and SUBROUTINE STRING PARAMETER.

We will use the example of a real parameter to show how the subroutine call works in conjunction with the SUBROUTINE REAL PARAMETER command line. Suppose we have a real parameter radius that is set to a value of 2.75 on the SUBROUTINE REAL PARAMETER command line:

SUBROUTINE REAL PARAMETER: radius = 2.75

Also suppose we have a call to aupst_get_real_parameter in the user subroutine:

call aupst_get_real_parameter("radius",cyl_radius,error_code)

In the call to aupst_get_real_parameter, we have var_name set to radius and var_value defined as the real FORTRAN variable cyl_radius. The call to aupst_get_real_parameter will assign the value 2.75 to the FORTRAN variable cyl_radius. A similar pattern is followed for integer and string parameters.

The arguments for the parameter-related query functions are described in Table Table 10.3, Table Table 10.4, and Table Table 10.5. The function is repeated before each table for quick reference.

aupst_get_real_param(string var_name, real var_value, int error_code)

Table 10.3 aupst_get_real_param Arguments
Parameter	Usage	Data Type	Description
var_name	Input	String	Name of a real-valued subroutine parameter, as defined in the Sierra/SM input file via the `SUBROUTINE REAL PARAMETER` command line.
var_value	Output	Real	Name of a real variable to be used in the FORTRAN subroutine. The FORTRAN variable var_value will be set to the value specified by the `SUBROUTINE REAL PARAMETER` command line.
error_code	Output	Integer	Error code indicating status of retrieving the parameter value from the input file. If the retrieval is successful, error_code is set to 0. If the parameter is not found or is the wrong type, error_code is set to a value other than 0.

aupst_get_integer_param(string var_name, int var_value,
                        int error_code)

Table 10.4 aupst_get_integer_param Arguments
Parameter	Usage	Data Type	Description
var_name	Input	String	Name of an integer-valued subroutine parameter, as defined in the Sierra/SM input file via the `SUBROUTINE INTEGER PARAMETER` command line.
var_value	Output	Integer	Name of an integer variable to be used in the FORTRAN subroutine. The FORTRAN variable var_value will be set to the value specified by the `SUBROUTINE INTEGER PARAMETER` command line.
error_code	Output	Integer	Error code indicating status of retrieving the parameter value from the input file. If the retrieval is successful, error_code is set to 0. If the parameter is not found or is the wrong type, error_code is set to a value other than 0.

aupst_get_string_param(string var_name, string var_value,
                       int error_code)

Table 10.5 aupst_get_string_param Arguments
Parameter	Usage	Data Type	Description
var_name	Input	String	Name of a string-valued subroutine parameter, as defined in the Sierra/SM input file via the `SUBROUTINE STRING PARAMETER` command line.
var_value	Output	String	Name of a string variable to be used in the FORTRAN subroutine. The FORTRAN variable var_value will be set to the value specified by the `SUBROUTINE STRING PARAMETER` command line.
error_code	Output	Integer	Error code indicating status of retrieving the parameter value from the input file. If the retrieval is successful, error_code is set to 0. If the parameter is not found or is the wrong type, error_code is set to a value other than 0.

10.2.1.2.2. Function Data Query

The function data query routine listed below may be used for extracting data from a function that is defined in a FUNCTION command block in the Sierra/SM input file. This query allows the user to directly access information stored in a function defined in the Sierra/SM input file.

aupst_evaluate_function(string func_name, real input_times[],
                        int num_times, real output_data[])

The arguments for this function are described in Table Table 10.6.

Table 10.6 aupst_evaluate_function Arguments
Parameter	Usage	Data Type	Description
func_name	Input	String	Name of the function to look up.
input_times(num_times)	Input	Real	Array of times used to extract values of the function.
num_times	Input	Integer	Length of the array input_times.
output_data(num_times)	Output	Real	Array of output values of the named function at the specified times.

10.2.1.2.3. Time Query

The time query function can be used to determine the current analysis time. This is the time associated with the new time step. This time may not be equivalent to the evaluation_time argument passed into the subroutine (see Section 10.2.1.1, Table Table 10.1) as some boundary conditions need to be evaluated at different times than others. The parameter of the time query function listed below is given in Table Table 10.7.

aupst_get_time(real time)

Table 10.7 aupst_get_time Argument
Parameter	Usage	Data Type	Description
time	Output	Real	Current analysis time.

10.2.1.2.4. Field Variables

Field variables (displacements, stresses, etc.) may be defined on groups of mesh entities. Many queries are available for getting and putting field variables. These queries involve passing in a set of mesh-entity identification numbers to receive field values on the mesh entities. There are query functions to check for the existence and size of a field, functions to retrieve the field values, and functions to store new variables in a field. The field query functions listed below can be used to extract any nodal or element variable field.

aupst_check_node_var(int num_nodes, int num_components,
                     int node_ids[], string var_name,
                     int error_code)

aupst_check_elem_var(int num_elems, int num_components,
                     int elem_ids[], string var_name,
                     int error_code)

aupst_get_node_var(int num_nodes, int num_components,
                   int node_ids[], real return_data[],
                   string var_name, int error_code)

aupst_get_elem_var(int num_elems, int num_components,
                   int elem_ids[], real return_data[],
                   string var_name, int error_code)

aupst_get_elem_var_offset(int num_elems, int num_components,
                          int offset, int elem_ids[],
                          real return_data[], string var_name,
                          int error_code)

aupst_put_node_var(int num_nodes, int num_components,
                   int node_ids[], real new_data[],
                   string var_name, int error_code)

aupst_put_elem_var(int num_elems, int num_components,
                   int elem_ids[], real new_data[],
                   string var_name, int error_code)

aupst_put_elem_var_offset(int num_elems, int num_components,
                          int offset, int elem_ids[],
                          real new_data[], string var_name,
                          int error_code)

The arrays where data are stored are static arrays. These arrays of a set size will be declared at the beginning of a user subroutine. The query functions to check for the existence and size of a field can be used to ensure that the size of the array of information being returned from Sierra/SM does not exceed the size of the array allocated by the user.

The arguments to field query functions are defined in Table Table 10.8 through Table Table 10.15. The function is repeated before each table for quick reference.

The var_name strings may be the name of any variable that could be used for code output and additionally may include the component syntax described in Section 9.1.

aupst_check_node_var(int num_nodes, int num_components,
                     int node_ids[], string var_name,
                     int error_code)

Table 10.8 aupst_check_node_var Arguments
Parameter	Usage	Data Type	Description
num_nodes	Input	Integer	Number of nodes used to extract field information.
num_components	Output	Integer	Number of components in the field information. A displacement field at a node has three components, for example.
node_ids (num_nodes)	Input	Integer	Array of size num_nodes listing the node identification number for each node where field information will be retrieved.
var_name	Input	String	Name of the field variable. The field variable must be a defined Sierra/SM variable.
error_code	Output	Integer	Error code indicating status of retrieving the field. If the retrieval is successful, error_code is set to 0. If a nonzero value is returned for error_code, the field variab ledoes not exist or is not defined on one or more of the input nodes.

aupst_check_elem_var(int num_elems, int num_components,
                     int elem_ids[], string var_name,
                     int error_code)

Table 10.9 aupst_check_elem_var Arguments
Parameter	Usage	Data Type	Description
num_elems	Input	Integer	Number of elements used to extract field information.
num_components	Output	Integer	Number of components in the field information. A stress field for an eight-node hexahedron element has six components, for example.
elem_ids (num_elems)	Input	Integer	Array of size num_elems listing the element identification number for each element where field information will be retrieved.
var_name	Input	String	Name of the field variable. The field variable must be a defined Sierra/SM variable.
error_code	Output	Integer	Error code indicating status of retrieving the field. If the retrieval is successful, error_code is set to 0. If a nonzero value is returned for error_code, the field variab ledoes not exist or is not defined on one or more of the input nodes.

aupst_get_node_var(int num_nodes, int num_components,
                   int node_ids[], real return_data[],
                   string var_name, int error_code)

Table 10.10 aupst_get_node_var Arguments
Parameter	Usage	Data Type	Description
num_nodes	Input	Integer	Number of nodes used to extract field information.
num_components	Input	Integer	Number of components in the field information. A displacement field at a node has three components, for example.
node_ids (num_nodes)	Input	Integer	Array of size num_nodes listing the node identification number for each node where field information will be retrieved.
return_data (num_components, num_nodes)	Output	Real	Array of size num_components \(\times\) num_nodes containing the field data at each node.
var_name	Input	String	Name of the field variable. The field variable must be a defined Sierra/SM variable.
error_code	Output	Integer	Error code indicating status of retrieving the field. If the retrieval is successful, error_code is set to 0. If a nonzero value is returned for error_code, the field variab ledoes not exist or is not defined on one or more of the input nodes.

aupst_get_elem_var(int num_elems, int num_components,
                   int elem_ids[], real return_data[],
                   string var_name, int error_code)

Table 10.11 aupst_get_elem_var Arguments
Parameter	Usage	Data Type	Description
num_elems	Input	Integer	Number of elements used to extract field information.
num_components	Input	Integer	Number of components in the field information. A stress field for an eight-node hexahedron element has six components, for example.
elem_ids (num_elems)	Input	Integer	Array of size num_elems listing the element identification number for each element where field information will be retrieved.
return_data (num_components, num_elems)	Output	Real	Array of size num_components \(\times\) num_elems containing the field data for each element.
var_name	Input	String	Name of the field variable. The field variable must be a defined Sierra/SM variable.
error_code	Output	Integer	Error code indicating status of retrieving the field. If the retrieval is successful, error_code is set to 0. If a nonzero value is returned for error_code, the field variable does not exist or is not defined on one or more of the input nodes.

aupst_get_elem_var_offset(int num_elems, int num_components,
                          int offset, int elem_ids[],
                          real return_data[], string var_name,
                          int error_code)

Table 10.12 aupst_get_elem_var_offset Arguments
Parameter	Usage	Data Type	Description
num_elems	Input	Integer	Number of elements used to extract field information.
num_components	Input	Integer	Number of components in the field information. A stress field for an eight-node hexahedron element has six components, for example.
offset	Input	Integer	Offset into var_name field variable at which to get data.
elem_ids (num_elems)	Input	Integer	Array of size num_elems listing the element identification number for each element where field information will be retrieved.
return_data (num_components, num_elems)	Output	Real	Array of size num_components \(\times\) num_elems containing the field data for each element.
var_name	Input	String	Name of the field variable. The field variable must be a defined Sierra/SM variable.
error_code	Output	Integer	Error code indicating status of retrieving the field. If the retrieval is successful, error_code is set to 0. If a nonzero value is returned for error_code, the field variable does not exist or is not defined on one or more of the input nodes.

aupst_put_node_var(int num_nodes, int num_components,
                   int node_ids[], real new_data[],
                   string var_name, int error_code)

Table 10.13 aupst_put_node_var Arguments
Parameter	Usage	Data Type	Description
num_nodes	Input	Integer	Number of nodes for which the user will specify the field data.
num_components	Input	Integer	Number of components in the field information. A displacement field at a node has three components, for example.
node_ids (num_nodes)	Input	Integer	Array of size num_nodes listing the node identification number for each node where field information will be retrieved.
new_data (num_components, num_nodes)	Input	Real	Array of size num_components \(\times\) num_nodes containing the new data for the field.
var_name	Input	String	Name of the field variable. The field variable must be a defined Sierra/SM variable.
error_code	Output	Integer	Error code indicating status of retrieving the field. If the retrieval is successful, error_code is set to 0. If a nonzero value is returned for error_code, the field variable does not exist or is not defined on one or more of the input nodes.

aupst_put_elem_var(int num_elems, int num_components,
                   int elem_ids[], real new_data[],
                   string var_name, int error_code)

Table 10.14 aupst_put_elem_var Arguments
Parameter	Usage	Data Type	Description
num_elems	Input	Integer	Number of elements for which the user will specify the field data.
num_components	Input	Integer	Number of components in the field information. A stress field for an eight-node hexahedron element has six components, for example.
elem_ids(num_elems)	Input	Integer	Array of size num_elems listing the element identification number for each element where field information will be retrieved.
new_data(num_components, num_elems)	Input	Real	Array of size num_components \(\times\) num_elems containing the new data for the field.
var_name	Input	String	Name of the field variable. The field variable must be a defined Sierra/SM variable.
error_code	Output	Integer	Error code indicating status of retrieving the field. If the retrieval is successful, error_code is set to 0. If a nonzero value is returned for error_code, the field variable does not exist or is not defined on one or more of the input nodes.

aupst_put_elem_var_offset(int num_elems, int num_components,
                          int offset, int elem_ids[],
                          real new_data[], string var_name,
                          int error_code)

Table 10.15 aupst_put_elem_var_offset Arguments
Parameter	Usage	Data Type	Description
num_elems	Input	Integer	Number of elements for which the user will specify the field data.
num_components	Input	Integer	Number of components in the field information. A stress field for an eight-node hexahedron element has six components, for example.
offse t	Input	Integer	Offset into var_name field variable at which to put data.
elem_ids(num_elems)	Input	Integer	Array of size num_elems listing the element identification number for each element where field information will be retrieved.
new_data(num_components, num_elems)	Input	Real	Array of size num_components \(\times\) num_elems containing the new data for the field.
var_name	Input	String	Name of the field variable. The field variable must be a defined Sierra/SM variable.
error_code	Output	Integer	Error code indicating status of retrieving the field. If the retrieval is successful, error_code is set to 0. If a nonzero value is returned for error_code, the field variable does not exist or is not defined on one or more of the input nodes.

10.2.1.2.5. Global Variables

Global variables may be extracted or set from user subroutines. A global variable has a single value for a given region. Global variables have limited support for parallel operations. The subroutine aupst_put_global_var attempts to immediately modify and optionally perform a parallel reduction on the value of a global variable. aupst_put_global_var can specify the variable reduction type “sum”, “min”, “max”, and “none.” If the “none” option is passed to the routine no global reduction operation will take place, only the processor local copy of the global variable will be modified. If any option other than “none” is used care must be taken to call aupst_put_global_var on all processors at the same time with the same arguments. Failure to call the routine from all processors will result in the code hanging. For some types of subroutines this is not possible or reliable. For example, a boundary condition subroutine may not be called at all on a processor that contains no nodes in the set of nodes assigned to the boundary condition. It is recommended that the aupst_put_global_var function only be used in conjunction with a user subroutine referenced in a USER OUTPUT command block (Section 9.4).

Only user-defined global variables may be modified by the user subroutine (see Section 10.1). However, any global variable that exists on the region may be checked or extracted. The following subroutine calls pertain to global variables:

aupst_check_global_var(int num_comp, string var_name
                       int error_code)

aupst_get_global_var(int num_comp, real return_data,
                     string var_name, int error_code)

aupst_put_global_var(int num_comp, real input_data,
                     string var_name,
                     string reduction_type,
                     int error_code)

The arguments for subroutine calls pertaining to global variables are defined in Table Table 10.16 through Table Table 10.18. The call is repeated before each table for quick reference.

aupst_check_global_var(int num_comp, string var_name
                       int error_code)

Table 10.16 aupst_check_global_var Arguments
Parameter	Usage	Data Type	Description
num_comp	Output	Integer	Number of components of the global variable.
var_name	Input	String	Name of the global variable.
error_code	Output	Integer	Error code indicating status of accessing the global variable. If there is no error in accessing this variable, error_code is set to 0. A nonzero value of error_code means theglobal variable does not exist or in some way cannot be accessed.

aupst_get_global_var(int num_comp, real return_data,
                     string var_name, int error_code)

Table 10.17 aupst_get_global_var Arguments
Parameter	Usage	Data Type	Description
num_comp	Input	Integer	Number of components of the global variable.
return_data	Output	Real	Value of the global variable.
var_name	Input	String	Name of the global variable.
error_code	Output	Integer	Error code indicating status of accessing the global variable. If there is no error in accessing this variable, error_code is set to 0. A nonzero value of error_code means the global variable does not exist or in some way cannot be accessed.

aupst_put_global_var(int num_comp, real input_data,
                     string var_name,
                     string reduction_type,
                     int error_code)

Table 10.18 aupst_put_global_var Arguments
Parameter	Usage	Data Type	Description
num_comp	Input	Integer	Number of components of the global variable.
input_data	Input	Real	New value of the global variable.
var_name	Input	String	Name of the global variable.
reduction_type	Input	String	Type of parallel reduction to perform on the variable. Options are “sum”, “min”, “max”, and “none.”
error_code	Output	Integer	Error code indicating status of accessing the global variable. If there is no error in accessing this variable, error_code is set to 0. A nonzero value of error_code means the global variable does not exist, in some way cannot be accessed, or may not be overwritten.

10.2.1.2.6. Topology Extraction

The element and surface subroutines operate on groups of elements or faces. The elements and faces may have a variety of topologies. Topology queries can be used to get topological data about elements and faces. The topology of an object is represented by an integer. The integer is formed from a function of the number of dimensions, vertices, and nodes of an object. The topology of an object is given by:

topology = num_node + 100 * num_vert + 10000 * num_dim

In a FORTRAN routine, the number of nodes can easily be extracted with the mod function:

num_node = mod(topo,100)
num_vert = mod(topo / 100, 100)
num_dim  = mod(topo / 10000, 100)

Table Table 10.19 lists the topologies currently in use by Sierra/SM.

Table 10.19 Topologies Used by Sierra/SM
Topology	Element / Face Type
00101	One-node particle
10202	Two-node beam, truss, or damper
20404	Four-node quadrilateral
20303	Three-node triangle
20304	Four-node triangle
20306	Six-node triangle
30404	Four-node tetrahedron
30410	Ten-node tetrahedron
30808	Eight-node hexahedron
30606	Six-node wedge
30505	Five-node pyramid

The following topology query functions are available in Sierra/SM:

aupst_get_elem_topology(int num_elems, int elem_ids[],
                        int topology[], int error_code)

aupst_get_elem_nodes(int num_elems, int elem_ids[],
                     int elem_node_ids[], int error_code)

aupst_get_face_topology(int num_faces, int face_ids[],
                        int topology[], int error_code)

aupst_get_face_nodes(int num_faces, int face_ids[],
                     int face_node_ids[], int error_code)

The arguments for the topology extraction functions are defined in Table Table 10.20 through Table Table 10.23. The function is repeated before each table for quick reference.

aupst_get_elem_topology(int num_elems, int elem_ids[],
                        int topology[], int error_code)

Table 10.20 aupst_get_elem_topology Arguments
Parameter	Usage	Data Type	Description
num_elems	Input	Integer	Number of elements from which the topology will be extracted.
elem_ids(num_elems)	Input	Integer	Array of length num_elems listing the element identification for each element from which the topology will be extracted.
topology(num_elems)	Output	Integer	Array of length num_elems that has the topology for each element. See Table 8.18.
error_code	Output	Integer	Error code indicating status of retrieving the element identification numbers. If the retrieval is successful, error_code is set to 0. A nonzero value is returned for error_code if one of the element identification numbers is not valid.

aupst_get_elem_nodes(int num_elems, int elem_ids[],
                     int elem_node_ids[], int error_code)

Table 10.21 aupst_get_elem_nodes Arguments
Parameter	Usage	Data Type	Description
num_elems	Input	Integer	Number of elements from which the topology will be extracted.
elem_ids(num_elems)	Input	Integer	Array of length num_elems listing the element identification for each element from which the topology will be extracted.
elem_node_ids(number of nodes for element type \(\times\) num_elems)	Output	Integer	Array containing the node identification numbers for each element requested. The length of the array is the total number of nodes contained in all elements. If the elements are eight-node hexahedra, then the number of nodes will be 8 \(\times\) num_elems. The first set of eight entries in the array will be the eight nodes defining the first element. The second set of eight entries will be the eight nodes defining the second element, and so on.
error_code	Output	Integer	Error code indicating status of retrieving the element identification numbers. If the retrieval is successful, error_code is set to 0. A nonzero value is returned for error_code if one of the element identification numbers is not valid.

aupst_get_face_topology(int num_faces, int face_ids[],
                        int topology[], int error_code)

Table 10.22 aupst_get_face_topology Arguments
Parameter	Usage	Data Type	Description
num_faces	Input	Integer	Number of faces from which the topology will be extracted.
face_ids(num_faces)	Input	Integer	Array of length num_faces listing the face identification for each face from which the topology will be extracted.
topology(num_faces)	Output	Integer	Array of length num_faces containing the output topologies of each face.
error_code	Output	Integer	Error code indicating status of retrieving the face identification numbers. If the retrieval is successful, error_code is set to 0. A nonzero value is returned for error_code if one of the face identification numbers is not valid.

aupst_get_face_nodes(int num_faces, int face_ids[],
                     int face_node_ids[], int error_code)

Table 10.23 aupst_get_face_nodes Arguments
Parameter	Usage	Data Type	Description
num_faces	Input	Integer	Number of faces from which the topology will be extracted.
face_ids(num_faces)	Input	Integer	Array of length num_faces listing the face identification for each face from which the topology will be extracted.
face_node_ids(number of nodes for face type \(\times\) num_faces)	Output	Integer	Array containing the node identification numbers for each face requested. The length of the array is the total number of nodes contained in all faces. If the faces are four-node quadrilaterals, then the number of nodes will be 4 \(\times\) num_faces. The first set of four entries in the array will be the four nodes defining the first face. The second set of four entries will be the four nodes defining the second face, and so on.
error_code	Output	Integer	Error code indicating status of retrieving the face identification numbers. If the retrieval is successful, error_code is set to 0. A nonzero value is returned for error_code if one of the face identification numbers is not valid.

10.2.1.3. Miscellaneous Query Functions

Many miscellaneous query functions are available for computing some commonly used quantities.

aupst_get_elem_centroid(int num_elems, int elem_ids[],
                        real centroids, int error_code)

aupst_get_point(string point_name, real point_coords,
                int error_code)

aupst_get_proc_num(proc_num)

The arguments for the miscellaneous query functions are defined in Table Table 10.24 through Table Table 10.26. The function is repeated before each table for quick reference.

aupst_get_elem_centroid(int num_elems, int elem_ids[],
                        real centroids[], int error_code)

Table 10.24 aupst_get_elem_centroid Arguments
Parameter	Usage	Data Type	Description
num_elems	Input	Integer	Number of elements for which to extract the topology.
elem_ids(num_elems)	Input	Integer	Array of length num_elems listing the element identification for each element for which the centroid will be computed.
centroids(3, num_elems)	Output	Real	Array of length 3 \(\times\) num_elems containing the centroid of each element.
error_code	Output	Integer	Error code indicating status of retrieving the element identification numbers. If the retrieval is successful, error_code is set to 0. A nonzero value is returned for error_code if one of the element identification numbers is not valid.

aupst_get_point(string point_name, real point_coords,
                int error_code)

Table 10.25 aupst_get_point Arguments
Parameter	Usage	Data Type	Description
point_name	Input	String	SIERRA name for a given point.
point_coords(3)	Output	Real	Array of length 3 containing the \(x\), \(y\), and \(z\) coordinates of the point.
error_code	Output	Integer	Error code indicating status of retrieving the point. If the retrieval is successful, error_code is set to 0. A nonzero value is returned for error_code if the point cannot be found

aupst_get_proc_num(proc_num)

Table 10.26 aupst_get_proc_num Argument
Parameter	Usage	Data Type	Description
proc_num	Output	Integer	Processor number of the calling process. This number can be used for informational purposes. A common example is that output could only be written by a single processor, e.g., processor 0, rather than by all processors.