Subroutine Type

Modeling

Definition

Used to specify a user defined curve element and its derivatives for a reference curve element. User defined curves are typically used in conjunction with point-to-curve, curve-to-curve, and curve-to-surface constraints.

Use

User defined reference parameter curve using a curve computed in a CURSUB:

<Reference_ParamCurve

    id                  = "111"

    is_u_closed         = "TRUE"

    u_start             = "-1."

    u_end               = "1."

    usrsub_param_string = "USER(100)"

    usrsub_dll_name     = "NULL">

</Reference_ParamCurve>

Calling Syntax

Fortran

SUBROUTINE CURSUB (ID, PAR, NPAR, ALPHA, IORD, IFLAG, VALUES)

C

void STDCALL CURSUB (int *id, double *par, int *npar, double *alpha, int *iord, int *iflag, double *values)

Python

def CURSUB(id, par, npar, alpha, iord, iflag):

    return values

MATLAB

function values = CURSUB(id, par, npar, alpha, iord, iflag)

Input Arguments

[integer] ID

The curve subroutine element identifier.

[double precision] PAR

An array that contains the constant arguments from the list provided in the user-defined statement.

[integer] NPAR

The number of entries in the PAR array.

[double precision] ALPHA

The value of the independent variable a used by the curve subroutine to evaluate the curve.

[logical] IFLAG

The initialization flag.

[integer] IORD

The order of the derivative that the curve subroutine returns.

0

The curve coordinates.

1

The curve first derivative with respect to the curvilinear coordinate ALPHA.

2

The curve second derivative with respect to the curvilinear coordinate ALPHA.

Output Values

[double precision] VALUES

The vector output value of dimension 3 that contains the x, y, and z coordinates of the generated curve.  Or, the first/second derivatives with respect to ALPHA, according to the IORD input parameter.

Example

def CURSUB(id, par, npar, alpha, iord, iflag):

    values = 3*[0.0]

    if iord == 0:

        values[0] =  par[0]*cos((alpha+1.0)*pi)

        values[1] =  0

        values[2] =  par[0]*sin((alpha+1.0)*pi)

    return values